COMPOSITIONS AND METHODS FOR TARGETING GENE DELIVERY VEHICLES

Abstract: The present invention provides a method for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising the step of administering to a warm-blooded animal a targeting element coupled to a first high affinity molecule of a high affinity binding pair, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and administering to the animal a gene delivery vehicle coupled to a second high affinity molecule of the high affinity binding pair, the second high affinity molecule being capable of specifically binding to the first high affinity molecule, such that the gene delivery vehicle is targeted to the selected cell type upon administration.

Description: Description COMPOSITIONS AND METHODS FOR TARGETING GENE DELIVERY VEHICLES Technical Field The present invention relates generally to compositions and methods for targeting gene delivery vehicles, and more specifically, to compositions and methods which utilize high affinity binding pairs in order to specifically target a gene delivery vehicle to a selected target cell. Background of the Invention Although many bacterial diseases can generally be easily treated with antibiotics, very few effective treatments or prophylactic measures presently exist for many viral, cancerous, and other nonbacterial diseases, such as genetic diseases. Traditional attempts to treat these diseases have employed the use of chemical drugs. In general, however, such drugs have lacked specificity and exhibited high overall toxicity. Various methods have therefore been developed in order to treat and/or prevent viral, cancerous, and genetic diseases that previously had not been amenable to traditional therapies as well as more recent therapies such as gene therapy. For example, retroviruses, which can replicate and integrate into a host cell's genome through a DNA intermediate, have been utilized in order to deliver a foreign gene into a target cell, in order to therapeutically effect that target cell (e.g., by killing the cell in the case of cancer, or by replacing a gene which is defective or not present in the cell in the case of diseases such as Adenosine Deaminase Deficiency) One difficulty with retroviruses, however, is that they generally only infect rapidly dividing cells, and moreover, are difficult to target to a selected cell type or tissue where it is desired to affect treatment. A number of methods have been attempted in order to target viral vectors such as retroviral vectors. For example, Neda et al. (J. Biol. Chem. 2*5/5(22): 14143-14146, 1991) chemically coupled α-lactose to viral particles, in order to produce viable viral particles capable of targeting human hepatocytes in vitro. Such a method, however, is of limited applicability, and has been only shown to allow the targeting of hepatocytes in tissue cultures. Others have attempted to link antibodies (Goud et al., Vir. 763:251-254, 1988) or antibody fragments (Roux et al., /WAS' ' flό: 070-9083, 1989; Etienne-Julan et al., J. of Gen. Vir. 73:3251-3255, 1992) with a viral particle, in order to target the viral particle to a specific cell type. Such methods, however, while producing binding of the retrovirus to a specific cell type did not result in the establishment of a proviral state (in Goud et al.) or resulted in only low levels of transduction (Roux et al and Etienne et al ) Moreover, none of these references described the use of such compositions in order to target cells m vivo Other attempts have also been made to specifically target a cell type by selecting a vehicle which normally infects that cell type For example, Shimada et al (J. Clin. Invest. 88 1043-1047, 1991) developed an HIV gene transfer system in order to specifically target CD4+ T cells One difficulty with such a system, however, is that it produced helper virus (HIV in the above case), which makes such a vector system unsuitable for the treatment of humans Other scientists have co-expressed the CD4 protein in-frame with the Avian Leukosis Virus transmembrane protein, or with the transmembrane protein of Murine Leukemia Virus, presumably in an attempt to target HIV infected T cells (Young et al Science 250 1421, 1990). While the CD4 protein was expressed by the virus, no evidence was provided which showed that such viral particles were able to transduce target T cells The present invention overcomes previous difficulties of delivering and specifically targeting gene delivery vehicles, and further provides other related advantages Summary of the Invention Briefly stated, the present invention provides compositions and methods for the targeting of gene delivery vehicles Within one aspect of the present invention, methods are provided for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising the steps of (a) administering to a warm-blooded animal a targeting element coupled to a first molecule of a high affinity binding pair, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and (b) administering to the animal a gene delivery vehicle coupled to a second molecule of said high affinity binding pair, the second molecule being capable of specifically binding to the first high affinity molecule such that the gene delivery vehicle is targeted to the selected cell type Within one embodiment, such methods further comprise, subsequent to the step of administering a coupled targeting element and prior to the step of administering a coupled gene delivery vehicle, administering to the animal a clearing agent Within another aspect of the present invention, methods are provided for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising the steps of (a) administering to a warm-blooded animal a gene delivery vehicle coupled to a first molecule of a high affinity binding pair, and (b) administering to the warm-blooded animal a targeting element coupled to a second molecule, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and the second molecule being capable of specifically binding to the first high affinity molecule, such that the gene delivery vehicle is targeted to the selected cell type Within various embodiments of the invention, a wide variety of targeting elements are provided, including for example, antibody and antibody fragments, bombesin, gastrin-release peptide, cell adhesion peptides, substance P, neuromedin-B, neuromedin-C, metenkephalin, EGF, alpha- and beta-TGF, neurotensin, melanocyte stimulating hormone, follicle stimulating hormone, lutenizing hormone, human growth hormone, cell surface receptors, low density lipoproteins, transferrin, erythropoietin, insulin and fibrinolytic enzymes. Other targeting elements include immune accessory molecules, which include for example, IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-1 1, IL-12, IL-13, IL-14, IL-15, α interferon, β interferon, γ interferon, GM-CSF, G-CSF and M-CSF. A wide variety of high affinity binding pairs are also provided for use in the above-described methods, including for example, biotin/avidin, cytostatin/papain, val- phosphonate/carboxypeptidase A, 4CABP/RuBisCo, and tobacco homworm diuretic hormone/tobacco hornworm diuretic hormone receptor, as well as antigen/antibody binding pairs. Within other embodiments of the invention, a wide variety of gene delivery vehicles are provided. Within one embodiment, the gene delivery vehicle is a retroviral vector construct. Such retroviral vector constructs may be readily constructed from a variety of viruses, including for example, ecotropic, amphotropic, xenotropic and polytropic retroviruses (see WO 92/05266). Representative examples of suitable viruses include Avian Leukosis Virus, Bovine Leukemia Virus, Mink-Cell Focus-Inducing Virus, Murine Sarcoma Virus, Reticuloendotheliosis Virus, Gibbon Ape Leukemia Virus, Mason Pfizer Leukemia Virus and Rous Sarcoma Virus. Particularly preferred retroviruses include Murine Leukemia Viruses such as Abelson, Friend, Graffi, Gross, Kirsten, Harvey Sarcoma Virus, Moloney Murine Leukemia Virus and Rauscher. Within other embodiments of the invention, the gene delivery vehicle may be selected from the group consisting of poliovirus vectors, rhinovirus vectors, pox virus vectors, canary pox virus vectors, vaccinia virus vectors, influenza virus vectors, adenovirus vectors, parvovirus vectors, adeno-associated viral vectors, herpesvirus vectors, SV 40 vectors, HIV vectors, measles virus vectors, astrovirus vectors, corona virus vectors, and alphaviral vectors. The present invention also provides a variety of non-viral gene delivery vehicles, including for example, polycation condensed nucleic acids, nucleic acid expression vectors, naked DNA, and certain eukaryotic cells (e.g., producer cells). Within other embodiments, the gene delivery vehicles described above contain or include a heterologous sequence, such as an antisense or ribozyme sequence, or genes which encode one or more cytotoxic proteins, immune accessory molecules, gene products that activate a compound with little or no cytotoxicity into a toxic product, disease-associated antigens, or replacement proteins. Representative examples of cytotoxic proteins include ricin, abrin, diphtheria toxin, cholera toxin, gelonin, pokeweed, antiviral protein, tritin, Shigella toxin, and Pseudomonas exotoxin A Representative examples of immune accessory molecules include IL-1, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL- 1 1, IL- 12, IL-13, IL-14, IL-15, α-interferon, γ-interferon, ICAM- 1, ICAM-2, β-microglobin, LFA3, and HLA class I and HLA class II molecules Representative examples of gene products which activate a compound with little or no cytotoxicity into a toxic product include HSVTK and VZVTK Representative examples of replacement proteins include Factor VIII, ADA, HPRT, CFTCR and the LDL Receptor Representative examples of disease-associated antigens include immunogenic portions of a virus selected from the group consisting of HBV, HCV, HPV, EBV, FeLV, FIV and HIV Within other aspects of the present invention, compositions are provided comprising one or more of the above-described gene delivery vehicles coupled to one member of a high affinity binding pair Within other aspects of the present invention, compositions are provided comprising a gene delivery vehicle which is coupled to a high affinity bind pair, which is in turn coupled to a targeting element Within preferred aspects of the present invention, the gene delivery vehicle is coupled to a member of the high affinity binding pair covalently, for example, by chemical methods Alternatively, a member of the high affinity binding pair may be expressed directly on the exterior of the gene delivery vehicle, or, otherwise incorporated integrally into the exterior surface (e.g., contained within the envelope) of the gene delivery vehicle These and other aspects of the present invention will become evident upon reference to the following detailed description and attached drawings In addition, various references are set forth below which describe in more detail certain procedures or compositions (e.g., plasmids, etc ), and are therefore incorporated by reference in their entirety Brief Description of the Drawings Figure 1 is a schematic illustration of pKS2+Eco57I-LTR(+) Figure 2 is a schematic illustration of pKS2+Eco57I-LTR(-) Figure 3 is a schematic illustration of pKS2+LTR-EcoRI Figure 4 is a schematic illustration of pRl Figure 5 is a schematic illustration of pR2 Figure 6 is a schematic illustration of pKTl Figure 7 is a schematic illustration of pRI-HIVenv Figure 8 is a schematic illustration of pR2-HIVenv Figure 9 is a representative "prewobble" sequence for a MoMLV gag/pol (see -//so SEQ I D Nos 1 1 and 12) Figure 10 is a representative "wobble" sequence for a MoMLV gag/pol (see also SEQ I D Nos 9 and 10) Figure 1 1 is a schematic illustration of pHCMV-PA Figure 12 is a schematic illustration of pCMV gag/pol Figure 13 is a schematic illustration of pCMVgpSma Figure 14 is a schematic illustration of pCMVgp-X Figure 15 is a schematic illustration of pCMV env-X Figure 16 is a schematic illustration of pRgpNeo Figures 17A, B and C comprise a table which sets forth a variety of retroviruses which may be utilized to construct the retroviral vector constructs, gag/pol expression cassettes and env expression cassettes of the present invention Figure 18 is a schematic illustration of pCMV Envam-Eag-X-less Figure 19 is a schematic illustration of the BAG vector Figure 20 is a schematic illustration of the BAGΔ vector Figure 21 is a schematic illustration of pMLV K Figure 22 is a schematic illustration of pNAGl Figure 23 is a schematic illustration of ReNEO Figure 24 is a schematic illustration of KT-1 Figure 25 is a schematic illustration of RXEN Figure 26 is a schematic illustration of RSEN Figure 27 provides a nucleotide and amino acid sequence of chicken avidin Figures 28A and 28B provide nucleic acid and amino acid sequences of a Murine Moloney Envelope Figure 29 is a schematic illustration of pCRII/N5 Figure 30 is a schematic illustration of pCRII/Al Figure 31 is a schematic illustration of pCRII/B14 Figure 32 is a schematic illustration of pCRII/C8 Figure 33 is a schematic illustration of RXEN/N5 Figure 34 is a schematic illustration of RXEN/A1 Figure 35 is a schematic illustration of RXEN/B 14 Figure 36 is a schematic illustration of RXEN/C8 Detailed Description of the Invention Prior to setting forth the invention, it may be helpful to an understanding thereof to first set forth definitions of certain terms that will be used hereinafter "Gene delivery vehicle" refers to a construct which is capable of delivering, and, within preferred embodiments expressing, one or more gene(s) or sequence(s) of interest in a host cell Representative examples of such vehicles include viral vectors, nucleic acid expression vectors, naked DNA, and certain eukaryotic cells (e.g., producer cells) Vehicles which are not considered to be within the scope of 'gene delivery vehicles' include liposomes Preferably, gene delivery vehicles of the present invention have a molecular weight of greater than about x kilodaltons, wherein x is selected from the group consisting of 50, 100, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1,000, 1,500, 2,000, 2,500, 3,000, 4,000, and 5,000 Within particularly preferred embodiments of the invention, the gene delivery vehicle includes a member of the high affinity binding pair (discussed below), either expressed on, or included as, an integral part of the exterior of the gene delivery vehicle "High Affinity Binding Pair" refers to a set a molecules which is capable of binding one another with a K D of less than 10 _ >'M, wherein y is selected from the group consisting of 8, 9, 10, 1 1, 12, 13, 14 and 15 As utilized herein, the "K D " refers to the disassociation constant of the reaction A + B ÷-' AB, wherein A and B are members of the high affinity binding pair (In addition, as should be understood by one of ordinary skill in the art, as the affinity of the two molecules increases, Kr j decreases ) Affinity constants may be readily determined by a variety of techniques, including for example by a Scatchard analysis (see Scatchard, Ann. N. Y. Acad. Sci. 51 660-672, 1949) Representative examples of suitable affinity binding pairs include biotin/avidin, cytostatin/papain, phosphonate/ carboxypeptidase A, and 4CABP/RuBisCo "Targeting element" refers to a molecule which is capable of specifically binding a selected cell type As utilized within the context of the present invention, targeting elements are considered to specifically bind a selected cell type when a biological effect of the coupled targeting element may be seen in that cell type, or, when there is greater than a 10 fold difference, and preferably greater than a 25, 50 or 100 fold difference between the binding of the coupled targeting element to target ceils and non-target cells Generally, it is preferable that the targeting element bind to the selected cell type with a K D of less than 10" 5 M, preferably less than 10" 6 M, more preferably less than 10" 7 M, and most preferably less than 10" 8 M (as determined by a Scatchard analysis, see Scatchard, Ann. N.Y. Acad Sci. 51 660-672, 1949) In addition it is generally preferred that the targeting element bind to the selected cell type with an affinity of at least 1 log (i.e., 10 times) less than the affinity constant of the high affinity binding pair (In other words, the Kp value will be at least 1 log or 10 fold greater ) Suitable targeting elements are preferably non-immunogenic, not degraded by proteolysis, and not scavenged by the immune system Particularly preferred targeting elements (which are conjugated to a member of the high affinity binding pair) should have a half-life (in the absence of a clearing agent) within an animal of between 10 minutes and 1 week Representative examples of suitable targeting elements are set forth below in more detail. "Clearing agent" refers to molecules which can bind and/or cross-link circulating coupled targeting elements. Preferably, the clearing agent is non-immunogenic, specific to the coupled targeting element, and large enough to avoid rapid renal clearance. In addition, the clearing agent is preferably not degraded by proteolysis, and not scavenged by the immune system. Particularly preferred clearing agents for use within the present invention include those which bind to the coupled targeting element at a site other than the affinity binding member, and most preferably, which bind in a manner that blocks the binding of the targeting element to its target. Numerous cleaving agents may be utilized within the context of the present invention, including for example those described by Marshall et al. in Brit. J. Cancer 69:502-507, 1994. "Retroviral vector construct" refers to an assembly which is, within preferred embodiments of the invention, capable of directing the expression of a sequence(s) or gene(s) of interest. Preferably, the retroviral vector construct should include a 5' LTR, a tRNA binding site, a packaging signal, one or more heterologous sequences, an origin of second strand DNA synthesis and a 3' LTR. A wide variety of heterologous sequences may be included within the vector construct, including for example, sequences which encode a protein (e.g., cytotoxic protein, disease-associated antigen, immune accessory molecule, or replacement protein), or which are useful as a molecule itself (_?. « £? * ., as a ribozyme or antisense sequence). Alternatively, the heterologous sequence may merely be a "stuffer" or "filler" sequence, which is of a size sufficient to allow production of viral particles containing the RNA genome. Preferably, the heterologous sequence is at least 1, 2, 3, 4, 5, 6, 7 or 8 kB in length. The retroviral vector construct may also include transcriptional promoter/enhancer or locus defining element(s), or other elements which control gene expression by means such as alternate splicing, nuclear RNA export, post-translational modification of messenger, or post-transcriptional modification of protein. Optionally, the retroviral vector construct may also include selectable markers such as Neo, TK, hygromycin, phleomycin, histidinol, or DHFR, as well as one or more specific restriction sites and a translation termination sequence. "Nucleic Acid Expression Vector" refers to an assembly which is capable of directing the expression of a sequence or gene of interest. The nucleic acid expression vector must include a promoter which, when transcribed, is operably linked to the sequence(s) or gene(s) of interest, as well as a polyadenylation sequence. Within certain embodiments of the invention, the nucleic acid expression vectors described herein may be contained within a plasmid construct. In addition to the components of the nucleic acid expression vector, the plasmid construct may also include a bacterial origin of replication, one or more selectable markers, a signal which allows the plasmid construct to exist as single-stranded DNA (e.g., a M13 origin of replication), a multiple cloning site, and a "mammalian" origin of replication (e.g., a SV40 or adenovirus origin of replication) As noted above, the present invention provides compositions and methods for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal Within one aspect of the present invention, such methods comprise the steps of (a) administering to a warm-blooded animal a targeting element coupled to a first high affinity molecule of a high affinity binding pair, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and (b) administering to the animal a gene delivery vehicle coupled to a second high affinity molecule of the high affinity binding pair, the second high affinity molecule being capable of specifically binding to the first high affinity molecule, such that the gene delivery vehicle is targeted to the selected cell type Various targeting elements, affinity binding pairs, and gene delivery vehicles may be utilized within the present invention, each of which is discussed in more detail below A TARGETING ELEMENTS A wide variety of targeting elements may be utilized within the context of the present invention, in order to specifically direct a gene delivery vehicle to a selected cell type Generally, targeting elements are proteins or peptides, although other non-proteinaceous molecules may also function as targeting elements For example, within one embodiment of the invention, antibodies may be utilized in order to target a selected cell type (see generally, Wilchek and Bayer, Anal. Biochem 171 1-32, 1988) Representative examples include anti- CD34 antibodies (e.g., 12 8 (Andrews et al , Blood 67 842, 1986), and My 10 (Civin et al., J. Immunol. 733.157, 1984, commercially available from Becton Dickinson under the designation HPCA-2)) which may be utilized to target the anti-CD34 antigen on stem cells, the anti-CD4 antibody which may be utilized to target CD4+ T-cells, anti-CD8 antibodies to target CD8+ cells, the HER2/neu monoclonal antibody 4D5 (Sarup et al , Growth Regiil. 1 72-82, 1991) to target ovarian and breast cells, the c-erbB-2 monoclonal antibody GFD- OA-pl85-l (Alper et al , Cell Growth Differ. 1 591-9, 1990) to target breast cells, the TAG72 monoclonal Ab CC49 and B72 3 (King et al , J. Biochem. 281 317-23, 1992) to target colon and breast cells, and the carcinoembryonic antigen monoclonal antibody ZCE025 (Nap et al , Cane. Res. 52 2329-39, 1992) to target colon carcinoma cells Other suitable targeting elements include hormones and hormone receptors Representative examples include follicle stimulating hormone and lutenizing hormone to ovary and testes cells, melanocyte stimulating hormone and epidermal growth factor to epidermal cells, and human growth hormone to mostly bone cells and skeletal muscle cells Within other embodiments, immune accessory molecules may be utilized to target specific receptors on various cells. Examples include interferon targeted to macrophages and natural killer cells, interleukins to T-lymphocytes, and erythropoietin and CSF to bone marrow cells. Within still other embodiments, peptides such as substance P may target neurons as a mediator of pain signals, neuromedin (Conlon, J. Neurochem. 57:988, 1988) may be utilized to target the cells of the uterus for contractile activity and proteins corresponding to ligands for known cell surface receptors such as insulin may be .utilized to target insulin receptors on cells for glucose regulation. Within yet other embodiments, other ligands and antibodies may be utilized to target selected cell types, including for example: monoclonal antibody c-SF-25 to target a 125kD antigen on human lung carcinoma (Takahashi et al, Science 259: 1460, 1993); antibodies to various lung cancer antigens (Souhami, Thorax -17:53-56, 1992); antibodies to human ovarian cancer antigen 14C 1 (Gallagher et al., Br. . Cancer 64:35-40, 1991); antibodies to H/Le- V /Le b antigens to target lung carcinoma (Masayuki et al., N. Eng. J. Med. 327: 14-18, 1992); nerve growth factor to target nerve growth factor receptors on neural tumors (Chao et al., Science 232:518, 1986); the Fc receptor to target macrophages (Anderson and Looney, Immun. Today 7:264-266, 1987); lectins (Sharon and Lis, Science 246:227, 1989); collagen type I to target colon cancer (Pullam and Bodmer, Nature 356:529, 1992); Interleukin-1 to target the lnterleukin-1 receptor on T cells (Fanslow et al., Science 248:739, 1990); acetylated low density lipoproteins ("LDL") to target macrophage scavenger receptors (and atherosclerotic plaques; see Brown et al., Ann. Rev. Biochem 52:223-261, 1983), as well as other acetylated molecules which target macrophage scavenger receptors (Paulinski et al., PNAS 56: 1372-1376, 1989); viral receptors (Haywood, J. Vir. 6<°(l): l-5, 1994); transferrin to target transferrin receptors on tumor cells (Huebers et al., Physio. Rev. 67:520, 582, 1987); vasoendothelial growth factor ("vegF") to target cells where increased vascularization occurs; and urokinase plasminogen activator receptor (UPAR). Alternatively, ligands may be selected from libraries created utilizing recombinant techniques (Scott and Smith, Science 249:386, 1990; Devlin et al.. Science 249:404, 1990; Houghten et al.. Nature 354:84 1991 ; Matthews and Wells, Science 260: 11 13, 1993; Νissim et al., EMBO J. 73(3):692-698, 1994), or equivalent techniques utilizing organic compound libraries. B. HIGH AFFINITY BINDING PAIRS In addition to targeting elements, the present invention also provides a wide variety of high affinity binding pairs. Representative examples of suitable affinity binding pairs include biotin/avidin with an affinity (K D ) of 10 **15 M (Richards, Meth. Enz. 184:3-5, 1990; Green, Adv. in Protein Chem. 29:85, 1985); cytostatin/papain with an affinity of 10" 14 M (Bjork and Ylinenjarvi, Biochemistry 29: 1770-1776, 1990); val-phosponate/carboxypeptidase A with an affinity of 10 **14 M (Kaplan and Bartlett, Biochemistry 30:8165-8170, 1991); 4CABP-RuBisCo with an affinity of 10" 13 M, (Schloss, J. Bio/. Chem. 263:4145-4150, 1988); and tobacco hornworm diuretic hormone/tobacco hornworm diuretic hormone receptor, with an affinity of 10- U M (Reagan et al., Arch. Insect Biochem. Physiol. 23: 135-145, 1993). A wide variety of other high affinity binding pairs may also be developed, for example, by preparing and selecting antibodies which recognize a selected antigen, and by further screening of such antibodies in order to select those with a high affinity (see generally, U.S. Patent Nos. RE 32,01 1, 4,902,614, 4,543,439, and 4,41 1,993; see also. Monoclonal Antibodies, Hybridomas: A New Dimension in Biological Analyses, Plenum Press, Kennett, McKearn, and Bechtol (eds.), 1980, and Antibodies: A Laboratory Manual, Harlow and Lane (eds.), Cold Spring Harbor Laboratory Press, 1988). Alternatively, antibodies or antibody fragments may also be produced and selected utilizing recombinant techniques (see William D. Huse et al., "Generation of a Large Combinational Library of the Immunoglobulin Repertoire in Phage Lambda," Science 246: 1275-1281, December 1989; see also L. Sastry et al., "Cloning of the Immunological Repertoire in Escherichia co/i for Generation of Monoclonal Catalytic Antibodies: Construction of a Heavy Chain Variable Region-Specific cDNA Library," Proc. Natl. Acad. Sci. USA <S'6:5728-5732, August 1989; see also Michelle Alting- Mees et al., "Monoclonal Antibody Expression Libraries: A Rapid Alternative to Hybridomas," Strategies in Molecular Biology 3: 1-9, January 1990; these references describe a commercial system available from Stratacyte, La Jolla, California, which enables the production of antibodies through recombinant techniques). As will be evident to one of ordinary skill in the art given the disclosure provided herein, either member (or molecule) of the affinity binding pair may be coupled to the gene delivery vehicle (or conversely, the targeting element). Nevertheless, within preferred embodiments of the invention, the larger of the two affinity binding pairs (e.g., avidin of the avidin/biotin pair) is coupled to gene delivery vehicle. C. GENE DELIVERY VEHICLES 1. Construction of retroviral gene delivery vehicles Within one aspect of the present invention, retroviral vector constructs are provided which are constructed to carry or express a selected gene(s) or sequence(s) of interest. Numerous retroviral gene delivery vehicles may be utilized within the context of the present invention, including for example EP 0,415,731 ; WO 90/07936; WO 91/0285, WO 9403622; WO 9325698; WO 9325234; U.S. Patent No. 5,219,740; WO 931 1230; WO 9310218; Vile and Hart, Cancer Res. 53:3860-3864, 1993; Vile and Hart, Cancer Res. 53:962-967, 1993; Ram et al., Cancer Res. 53:83-88, 1993; Takamiya et al., J. Neurosci. Res. 33:493-503, 1992; Baba et al., J. Ne rosurg. 79:729-735, 1993 (U.S. Patent No. 4,777,127, GB 2,200,651, EP 0,345,242 and W0 1/02805). Retroviral gene delivery vehicles of the present invention may be readily constructed from a wide variety of retroviruses, including for example, B, C, and D type retroviruses as well as spumaviruses and lentiviruses (see RNA Tumor Viruses, Second Edition, Cold Spring Harbor Laboratory, 1985). Briefly, viruses are often classified according to their morphology as seen under electron microscopy. Type "B" retroviruses appear to have an eccentric core, while type "C" retroviruses have a central core. Type "D" retroviruses have a morphology intermediate between type B and type C retroviruses. Representative examples of suitable retroviruses include those set forth below in Figures 17 A, B and C (see RNA Tumor Viruses at pages 2-7), as well as a variety of xenotropic retroviruses (e.g., NZB-X1, NZB-X2 and NZB 9 _ι (see O'Neill et al., J. Vir. 53: 100-106, 1985)) and polytropic retroviruses (e.g., MCF and MCF-MLV (see Kelly et al., J. Vir. 45(\):291-298, 1983)). Such retroviruses may be readily obtained from depositories or collections such as the American Type Culture Collection ("ATCC"; Rockville, Maryland), or isolated from known sources using commonly available techniques. Particularly preferred retroviruses for the preparation or construction of retroviral gene delivery vehicles of the present invention include retroviruses selected from the group consisting of Avian Leukosis Virus, Bovine Leukemia Virus, Murine Leukemia Virus, Mink-Cell Focus-Inducing Virus, Murine Sarcoma Virus, Reticuloendotheliosis virus and Rous Sarcoma Virus. Particularly preferred Murine Leukemia Viruses include 4070A and 1504A (Hartley and Rowe, J. Virol. 79: 19-25, 1976), Abelson (ATCC No. VR-999), Friend (ATCC No. VR-245), Graffi, Gross (ATCC No. VR-590), Kirsten, Harvey Sarcoma Virus and Rauscher (ATCC No. VR-998), and Moloney Murine Leukemia Virus (ATCC No. VR- 190). Particularly preferred Rous Sarcoma Viruses include Bratislava, Bryan high titer (e.g., ATCC Nos. VR-334, VR-657, VR-726, VR-659, and VR-728), Bryan standard, Carr-Zilber, Engelbreth-Holm, Harris, Prague (e.g., ATCC Nos. VR-772, and 45033), and Sch idt- Ruppin (e.g. ATCC Nos. VR-724, VR-725, VR-354). Any of the above retroviruses may be readily utilized in order to assemble or construct retroviral gene delivery vehicles given the disclosure provided herein, and standard recombinant techniques (e.g., Sambrook et al. Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory Press, 1989; Kunkle, PNAS 52:488, 1985). In addition, within certain embodiments of the invention, portions of the retroviral gene delivery vehicles may be derived from different retroviruses. For example, within one embodiment of the invention, retroviral LTRs may be derived from a Murine Sarcoma Virus, a tRNA binding site from a Rous Sarcoma Virus, a packaging signal from a Murine Leukemia Virus, and an origin of second strand synthesis from an Avian Leukosis Virus. Within one aspect of the present invention, retroviral vector constructs are provided comprising a 5' LTR, a tRNA binding site, a packaging signal, one or more heterologous sequences, an origin of second strand DNA synthesis and a 3' LTR, wherein the vector construct lacks gag/pol or env coding sequences. Briefly, Long Terminal Repeats ("LTRs") are subdivided into three elements, designated U5, R and U3. These elements contain a variety of signals which are responsible for the biological activity of a retrovirus, including for example, promoter and enhancer elements which are located within U3. LTRs may be readily identified in the provirus due to their precise duplication at either end of the genome. The tRNA binding site and origin of second strand DNA synthesis are also important for a retrovirus to be biologically active, and may be readily identified by one of skill in the art. For example, retroviral tRNA binds to a tRNA binding site by Watson-Crick base pairing, and is carried with the retrovirus genome into a viral particle. The tRNA is then utilized as a primer for DNA synthesis by reverse transcriptase. The tRNA binding site may be readily identified based upon its location just downstream from the 5' LTR. Similarly, the origin of second strand DNA synthesis is, as its name implies, important for the second strand DNA synthesis of a retrovirus. This region, which is also referred to as the poly-purine tract, is located just upstream of the 3' LTR. In addition to a 5' and 3' LTRs, tRNA binding site, and origin of second strand DNA synthesis, certain preferred retroviral vector constructs which are provided herein also comprise a packaging signal, as well as one or more heterologous sequences, each of which is discussed in more detail below. Within one aspect of the invention, retroviral vector constructs are provided which lack both gag/pol and env coding sequences. As utilized within the context of the present invention, a packaging signal should be understood to refer to that sequence of nucleotides which is not required for synthesis, processing or translation of viral RNA or assembly of virions, but which is required in cis for encapsidation of genomic RNA (see Mann et al., Cell 33: 153-159, 1983; RNA Tumor Viruses, Second Edition, supra). Further, as utilized herein, the phrase "lacks gag pol or env coding sequences" should be understood to refer to retrovectors which contain less than 20, preferably less than 15, more preferably less than 10, and most preferably less than 8 consecutive nucleotides which are found in gag/pol or env genes, and in particular, within gag pol or env expression cassettes that are used to construct packaging cell lines for the retroviral vector construct. Representative examples of such retroviral vector constructs are set forth in more detail below and in Example 1. As an illustration, within one embodiment of the invention construction of retroviral vector constructs which lack gag/pol or env sequences may be accomplished by preparing retroviral vector constructs which lack an extended packaging signal. As utilized herein, the phrase "extended packaging signal" refers to a sequence of nucleotides beyond the minimum core sequence which is required for packaging, that allows increased viral titer due to enhanced packaging. As an example, for the Murine Leukemia Virus MoMLV, the minimum core packaging signal is encoded by the sequence (counting from the 5' LTR cap site) from approximately nucleotide 144 of SEQ. I.D. No. 1, up through the Pst I site (nucleotide 567 of SEQ. I.D. No. 1 ). The extended packaging signal of MoMLV includes the sequence beyond nucleotide 567 up through the start of the gag/pol gene (nucleotide 621), and beyond nucleotide 1040. Thus, within this embodiment retroviral vector constructs which lack extended packaging signal may be constructed from the MoMLV by deleting or truncating the packaging signal downstream of nucleotide 567. Within other embodiments of the invention, retroviral vector constructs are provided wherein the packaging signal that extends into, or overlaps with, retroviral gag/pol sequence is deleted or truncated. For example, in the representative case of MoMLV, the packaging signal is deleted or truncated downstream of the start of the gag/pol gene (nucleotide 621 of SEQ ID NO: 1 ). Within preferred embodiments of the invention, the packaging signal is terminated at nucleotide 570, 575, 580, 585, 590, 595, 600, 610, 615 or 617 of SEQ ID NO: 1. Within other aspects of the invention, retroviral vector constructs are provided which include a packaging signal that extends beyond the start of the gag/pol gene (e.g., for MoMLV, beyond nucleotide 621 of SEQ ID NO: 1). When such retroviral vector constructs are utilized, it is preferable to utilize packaging cell lines for the production of recombinant viral particles wherein the 5' terminal end of the gag/pol gene in a gag/pol expression cassette has been modified to contain codons which are degenerate for gag. Such gag/pol expression cassettes are described in more detail below in section 2, and in Example 3. Within other aspects of the present invention, retroviral vector constructs are provided comprising a 5' LTR, a tRNA binding site, a packaging signal, an origin of second strand DNA synthesis and a 3' LTR, wherein the retrovector plasmid construct does not contain a retroviral nucleic acid sequence upstream of the 5' LTR. As utilized within the context of the present invention, the phrase "does not contain a retroviral nucleic acid sequence upstream of the 5' LTR" should be understood to mean that the retrovector plasmid construct contains less than 20, preferably less than 15, more preferably less than 10, and most preferably less than 8 consecutive nucleotides which are found in a retrovirus, and more specifically, in a retrovirus which is homologous to the retroviral vector construct, upstream of and/or contiguous with the 5' LTR. Within preferred embodiments, the retrovector plasmid constructs do not contain an env coding sequence (as discussed below) upstream of the 5' LTR. A particularly preferred embodiment of such retrovector plasmid constructs is set forth in more detail below in Example 1. Within a further aspect of the present invention, retrovector plasmid constructs are provided comprising a 5' LTR, a tRNA binding site, a packaging signal, an origin of second strand DNA synthesis and a 3' LTR, wherein the retrovector plasmid construct does not contain a retroviral packaging signal sequence downstream of the 3' LTR. As utilized herein, the term "packaging signal sequence" should be understood to mean a sequence sufficient to allow packaging of the RNA genome. A representative example of such a retroviral vector construct is set forth in more detail below in Example 1. Packaging cell lines suitable for use with the above-described retroviral vector constructs may be readily prepared (see U.S. Serial No. 08/240,030, filed May 9, 1994; see also WO 92/05266), and utilized to create producer cell lines (also termed vector cell lines or "VCLs") for the production of recombinant vector particles. In particular, a variety of gag/pol expression cassettes are provided which, in combination with the retroviral vector constructs and env expression cassettes also described herein, enable the construction of packaging cell lines and producer cell lines which preclude the formation of replication competent virus. Briefly, retroviral gag/pol genes contain a gag region which encodes a variety of structural proteins that make up the core matrix and nucleocapsid, and a pol region which contains genes which encode (l) a protease for the processing of gag/pol and env proteins, (2) a reverse transcriptase polymerase, (3) an RNase H, and (4) an integrase, which is necessary for integration of the retroviral provector into the host genome. Although retroviral gag/pol genes may be utilized to construct the gag/pol expression cassettes of the present invention, a variety of other non-retroviral (and non-viral) genes may also be utilized to construct the gag/pol expression cassette. For example, a gene which encodes retroviral RNase H may be replaced with genes which encode bacterial (e.g., E. coli or Thermus thermophilus) RNase H. Similarly, a retroviral integrase gene may be replaced by other genes with similar function (e.g., yeast retrotransposon TY3 integrase). Within one aspect of the invention, gag/pol expression cassettes are provided comprising a promoter operably linked to a gag/pol gene, and a polyadenylation sequence, wherein the gag/pol gene has been modified to contain codons which are degenerate for gag. Briefly, as noted above, in wild-type retrovirus the extended packaging signal of the retrovirus overlaps with sequences which encode gag and pol. Thus, in order to eliminate the potential of crossover between the retroviral vector construct and the gag/pol expression cassette, as well as to eliminate the possiblity of co-encapsidation of the gag/pol expression cassette and replication competent virus or retroviral vector constructs, sequences of overlap should be eliminated. Within one embodiment of the invention, elimination of such overlap is accomplished by modifying the gag' pol gene (and more specifically, regions which overlap with the retroviral vector construct, such as the extended packaging signal) to contain codons that are degenerate (i.e., that "wobble") for gag. In particular, within preferred embodiments of the invention codons are selected which encode biologically active gag pol protein (i.e., capable of producing a competent retroviral particle, in combination with an env expressing element, and a RNA genome), and which lack any packaging signal sequence, including in particular, extended packaging signal sequence. As utilized herein, the phrase "lacks any retroviral packaging signal sequence" should be understood to mean that the gag/pol expression cassette contains less than 20, preferably less than 15, more preferably less than 10, and most preferably less than 8 consecutive nucleotides which are identical to a sequence found in a retroviral packaging signal (e.g., in the case of MoMLV, extending up and through the Xho I site at approximately nucleotide number 1561 ). A particularly preferred example of such modified codons which are degenerate for gag is shown in Figure 10, and in Example 3, although the present invention should not be so limited. In particular, within other embodiments, at least 25, 50, 75, 100, 125 or 135 gag codons are modified or "wobbled" from the native gag sequence within the gag/pol expression cassettes of the present invention. In addition to eliminating overlap between the retroviral vector construct and the gag/pol gene, it is also preferable to eliminate any potential overlap between the gag/pol gene and the env gene in order to prohibit the possibility of homologous recombination. This may be accomplished in at least two principal ways: (1) by deleting a portion of the gag/pol gene which encodes the integrase protein, and in particular, that portion of the gene which encodes the integrase protein which overlaps with the env coding sequence, or (2) by selecting codons which are degenerate for integrase and/or env. Thus, within one aspect of the present invention gag/pol expression cassettes are provided comprising a promoter operably linked to a gag/pol gene, and a polyadenylation sequence or signal, wherein a 3' terminal end of the gene has been deleted without effecting the biological activity of the integrase. (The biological activity of integrase may be readily determined by detection of an integration event, either by DNA analysis or by expression of a transduced gene; see Roth et al., J. Vir. 65(4):2141-2145, 1991.) As an example, in the Murine Leukemia Virus MoMLV (SEQ ID. NO. 1 ), the gag/pol gene is encoded by nucleotides 621 through 5834. Within this sequence, the protein integrase is encoded by nucleotides 4610 through nucleotide 5834. A portion of the gag/pol sequence which encodes integrase also encodes env (which begins at nucleotide 5776). Thus, within one embodiment of the invention, the 3' terminal end of the gag/pol gene is deleted or truncated in order to prevent crossover with the env gene, without effecting the biological activity of the integrase. Within other preferred embodiments, the gag/pol gene is deleted at any nucleotide downstream (3') from the beginning of the integrase coding sequence, and preferably prior to the start of the env gene sequence Within one embodiment, the sequence encoding gag/pol is a MoMLV sequence, and the gag'pol gene is deleted at any nucleotide between nucleotides 4610 and 5576 (of SEQ I.D No 1 ), including for example, at nucleotides 5775, 5770, 5765, 5760, 5755, 5750 Within other embodiments of the invention, the gag/pol expression cassette contains sequences encoding gag/pol (and including integrase), while lacking any sequence found in an env gene The phrase "lacking any sequence found in an env gene" should be understood to mean that the gag'pol expression cassette does not contain at least 20, preferably at least 15, more preferably at least 10, and most preferably less than 8 consecutive nucleotides which are identical to an env sequence, and preferably which are found in an env expression cassette which will be utilized along with the gag/pol expression cassette to form a packaging cell Such expression cassettes may be readily prepared by selecting codons which are degenerate for integrase, and which do not encode biologically active env (See Morgenstern and Land, Nitc. Acids Res 18 3587-3596, 1990 ) Within other embodiments of the invention, the gag/pol expression cassette contains a heterologous promoter, and/or heterologous polyadenylation sequence As utilized herein, "heterologous" promoters or polyadenylation sequences refers to promoters or polyadenylation sequences which are from a different source from which the gag/pol gene (and preferably the env gene and retroviral vector construct) is derived from Representative examples of suitable promoters include the Cytomegalovirus Immediate Early ("CMV IE") promoter, the Herpes Simplex Virus Thymidine Kinase ("HSVTK") promoter, the Rous Sarcoma Virus ("RSV") promoter, the Adenovirus major-late promoter and the SV 40 promoter Representative examples of suitable polyadenylation signals include the SV 40 late polyadenylation signal and the SV40 early polyadenylation signal Within preferred aspects of the present invention, gag/pol expression cassettes such as those described above will not co-encapsidate along with a replication competent virus Within related aspects, env expression cassettes are provided which, in combination with the gag/pol expression cassettes and retroviral vector constructs described above, preclude formation of replication competent virus by homologous recombination, as well as to confer a particular specificity of the resultant vector particle (e.g., amphotropic, ecotropic, xenotropic or polytropic, see Figure 17, as well as the discussion above) Briefly, in a wild-type retrovirus the env gene encodes two principal proteins, the surface glycoprotein "SU" and the transmembrane protein "TM", which are translated as a polyprotein, and subsequently separated by proteolytic cleavage Representative examples of the SU and TM proteins are the gpl20 protein and gp41 protein in HIV, and the gp70 protein and pl5e protein in MoMLV In some retroviruses, a third protein designated the "R" peptide" of undetermined function, is also expressed from the env gene and separated from the polyprotein by proteolytic cleavage In the Murine Leukemia Virus MoMLV, the R peptide is designated "p2". A wide variety of env expression cassettes may be constructed given the disclosure provided herein Within one aspect, env expression cassettes are provided comprising a promoter operably linked to an env gene, wherein no more than 6, 8, 10, 15, or 20 consecutive retroviral nucleotides are included upstream (5') of and/or contiguous with said env gene. Within other aspects of the invention, env expression cassettes are provided comprising a promoter operably linked to an env gene, wherein the env expression cassette does not contain a consecutive sequence of greater than 20, preferably less than 15, more preferably less than 10, and most preferably less than 8 or 6 consecutive nucleotides which are found in a gag/pol gene, and in particular, in a gag/pol expression cassette that will be utilized along with the env expression cassette to create a packaging cell line Within another aspect, env expression cassettes are provided comprising a promoter operably linked to an env gene, and a polyadenylation sequence, wherein a 3' terminal end of the env gene has been deleted without effecting the biological activity of env. As utilized herein, the phrase "biological activity of env" refers to the ability of envelop protein to be expressed on the surface of a virus or vector particle, and to allow for a successful infection of a host cell One practical method for assessing biological activity is to transiently transfect the env expression cassette into a cell containing a previously determined functional gag/pol expression cassette, and a retroviral vector construct which expresses a selectable marker. A biologically functional env expression cassette will allow vector particles produced in that transfected cell, to transmit the selectable marker to a naive sensitive cell such that it becomes resistant to the marker drug selection Within a preferred embodiment of the invention, the 3' terminal end of the env gene is deleted or truncated such that a complete R peptide is not produced by the expression cassette In the representative example of MoMLV, sequence encoding the R peptide (which begins at nucleotide 7734) is deleted, truncated, or, for example, terminated by insertion of a stop codon at nucleotide 7740, 7745, 7747, 7750, 7755, 7760, 7765, 7770, 7775, 7780, or any nucleotide in between Within yet another aspect, env expression cassettes are provided which contain a heterologous promoter, and/or heterologous polyadenylation sequence. As utilized herein, "heterologous" promoters or polyadenylation sequences refers to promoters or polyadenylation sequences which are from a different source from which the gag/pol gene (and preferably the env gene and retroviral vector construct) is derived from Representative examples of suitable promoters include the CMV IE promoter, the HSVTK promoter, the RSV promoter, the Adenovirus major-late promoter and the SV 40 promoters. Representative examples of suitable polyadenylation signals include the SV 40 late polyadenylation signal and the SV40 early polyadenylation signal. 2 Alphavirus delivery vehicles The present invention also provides a variety of Alphavirus vectors which may function as gene delivery vehicles. For example, the Sindbis virus is the prototype member of the alphavirus genus of the togavirus family The unsegmented genomic RNA (49S RNA) of Sindbis virus is approximately 1 1,703 nucleotides in length, contains a 5' cap and a 3' poly- adenylated tail, and displays positive polarity. Infectious enveloped Sindbis virus is produced by assembly of the viral nucleocapsid proteins onto the viral genomic RNA in the cytoplasm and budding through the cell membrane embedded with viral encoded glycoproteins Entry of virus into cells is by endocytosis through clatharin coated pits, fusion of the viral membrane with the endosome, release of the nucleocapsid, and uncoating of the viral genome During viral replication the genomic 49S RNA serves as template for synthesis of the complementary negative strand. This negative strand in turn serves as template for genomic RNA and an internally initiated 26S subgenomic RNA The Sindbis viral nonstructural proteins are translated from the genomic RNA while structural proteins are translated from the subgenomic 26S RNA. All viral genes are expressed as a polyprotein and processed into individual proteins by post translational proteolytic cleavage The packaging sequence resides within the nonstructural coding region, therefore only the genomic 49S RNA is packaged into virions. Several different Alphavirus vector systems may be constructed and utilized within the present invention. Representative examples of such systems include those described within U.S. Patent Nos 5,091,309 and 5,217,879, PCT Publication WO 92/10578, and U.S. Serial Nos 08/405,627 and 08/404,796. Particularly preferred Alphavirus vectors for use within the present invention include those which are described within WO 94/10469. Briefly, within one embodiment, Alphavirus constructs are provided comprising a 5' sequence which is capable of initiating transcription of an Alphavirus, a nucleotide sequence encoding Alphavirus non-structural proteins, an Alphavirus viral junction region which may, in certain embodiments, be inactivated such that viral transcription of the subgenomic fragment is prevented or modified such that viral transcription is reduced, and a Sindbis RNA polymerase recognition sequence. Within yet another aspect, eukaryotic layered vector initiation systems may be utilized as a gene delivery vehicle. Such systems generally comprise a 5' promoter, a construct which is capable of expressing a heterologous nucleotide sequence that is capable of replication in a cell either autonomously or in response to one or more factors, and a transcription termination sequence In still further embodiments, the vector constructs described above contain no Alphavirus structural proteins in the vector constructs the selected heterologous sequence may be located downstream from the viral junction region, in the vector constructs described above having a second viral junction, the selected heterologous sequence may be located downstream from the second viral junction region, where the heterologous sequence is located downstream, the vector construct may comprise a polylinker located between the viral junction region and said heterologous sequence, and preferably the polylinker does not contain a wild-type Alphavirus restriction endonuclease recognition sequence 3 Other viral zene delivery vehicles In addition to retroviral vectors and Alphavirus vectors, numerous other viral vectors systems may also be utilized as a gene delivery vehicle Representative examples of such gene delivery vehicles include poliovirus (Evans et al , Nature 339 385-388, 1989, and Sabin, J. Biol. Standardization 1 1 15- 1 18, 1973), rhinovirus, pox viruses, such as canary pox virus or vaccinia virus (Fisher-Hoch et al , PNAS 86 317-321, 1989, Flexner et al , Ann. N.Y. Acad. Sci. 569 86-103, 1989, Flexner et al , Vaccme 5 17-21, 1990, U S Patent Nos 4,603,112, 4,769,330 and 5,017,487, WO 89/01973, WO 95/0924), SV40 (Mulligan et al , Nature 277 108-1 14, 1979), influenza virus (Luytjes et al , Cell 59 1 107-1 1 13, 1989, McMicheal et al , N Eng. J. Med. 309 13-17, 1983, and Yap et al , Nature 273 238-239, 1978), adenovirus (Berkner, Biotechniqiies 6 616-627, 1988, Rosenfeld et al , Science 252.431-434, 1991 , WO 93/9191 , Kolls et al , PNAS 97(1) 215-219, 1994, Kass-Eisler et al , PNAS 90(24) 11498-502, 1993, Guzman et al , Circulation 88(6) 2838-48, 1993, Guzman et al , Cir. Res. 73(6) 1202-1207, 1993, Zabner et al , Cell 75(2) 207-216, 1993, Li et al , Hum. Gene Ther. 4(4) 403-409, 1993, Caillaud et al , Em: J. Neuro.sci. 5( 10) 1287-1291, 1993, Vincent et al , Nat. Genet. 5(2) 130-134, 1993, jaffe et al , Nat. Genet. 7(5) 372-378, 1992, and Levrero et al , Gene 101(2) 195-202, 19 1 ), parvovirus such as adeno-associated virus (Samulski et al , J. Vir. 63 3822-3828, 1989, Mendelson et al , Virol. 166 154-165, 1988, PA 7/222,684, Flotte et al , PNAS 90(22) 10613-10617, 1993), herpes (Kit, Adv. Exp. Med. Biol. 275.219-236, 1989, U S Patent No 5,288,641 ), SV40, HIV (Poznansky, J. Virol. 65 532- 536, 1991), measles (EP 0 440,219), astrovirus (Munroe, S S et al , J. Vir. 67 3611-3614, 1993), Semliki Forest Virus, and coronavirus, as well as other viral systems (e.g., EP 0,440,219, WO 92/06693, U S Patent No 5, 166,057) In addition, viral carriers may be homologous, non-pathogenic(defective), replication competent virus (e g , Overbaugh et al , Science 239 906-910, 1988), and nevertheless induce cellular immune responses, including CTL 4. Non-viral zene delivery vehicles In addition to the above viral-based vectors, numerous non-viral gene delivery vehicles may likewise be utilized within the context of the present invention. Representative examples of such gene delivery vehicles include direct delivery of nucleic acid expression vectors, naked DNA alone (WO 90/1 1092), polycation condensed DNA linked or unlinked to killed adenovirus (Curiel et al., Hum. Gene Ther. 3: 147-154, 1992), DNA ligand linked to a ligand with or without one of the high affinity pairs described above (Wu et al., J. of Biol. Chem 26^:16985-16987, 1989), and certain eukaryotic cells (e.g., producer cells - see U.S. Serial No. 08/240,030, filed May 9, 1994, and WO 92/05266). D. COUPLING OF A GENE DELIVERY VEHICLE OR TARGETING ELEMENT TO A MEMBER OF THE AFFINITY BINDING PAIR As noted above, the present invention provides gene delivery vehicles which have been coupled to a member of a high affinity binding pair (also referred to as the "coupled gene delivery vehicle"), as well as targeting elements which have coupled to a member of a high affinity binding pair (also referred to as the "coupled targeting element"). As utilized within the context of the present invention, the term "coupled" may refer to either noncovalent or covalent interactions, although generally covalent bonds are preferred. Numerous methods may be utilized in order to couple one member of a high affinity binding pair to either a gene delivery vehicle or a targeting element, including for example use of crosslinking agents such as N-succinimidyl-3-(2-pyridyl dithio) propionate ("SPDP"; Carlson et al., J. Biochem. 773:723, 1978); Sulfosuccinimidyl 4-N-maIeimidomethyl) cyclohexane-1-carboxylate ("SulfoSMCC"); l-ethyl-3 (3-dimethylaminopropyl) carbodiimide ("EDC"); Bis-diazobenzidine ("BDB"); and Periodic acid / Schiffs base. Within certain embodiments of the invention, a member of the high affinity binding pair is either expressed on, or included as an integral part of, the exterior (e.g., envelope) of the gene delivery vehicle. For example, within one embodiment of the invention a member of the affinity binding pair is co-expressed along with the envelope protein of a viral gene delivery vehicle, as a hybrid protein. More particularly, within certain embodiments the coding region of all or a portion of an affinity binding agent may be fused in-frame with a sequence which encodes an envelope gene. Such affinity binding agent coding regions may be fused to either the amino or carboxyl termini of an envelope gene, or placed within an envelope gene (either by replacement of a portion of the envelope gene, or in addition to the envelope gene). Of particular interest are variable regions A and B, which contain the wild- type receptor binding determinants for ecoptropic and amphotropic envelopes, respectively. A representative example of such fusion proteins is described in more detail below in Example 1 1 HETEROLOGOUS SEQUFNCES Any of the gene delivery vehicles described above may include, contain (and/or express) one or more heterologous sequences A wide variety of heterologous sequences may be utilized within the context of the present invention, including for example, cytotoxic genes, disease-associated antigens, antisense sequences, sequences which encode gene products that activate a compound with little or no cytotoxicity (i.e., a "prodrug") into a toxic product, sequences which encode immunogenic portions of disease-associated antigens, sequences which encode immune accessory molecules and sequences which encode a desired protein (e.g., a therapeutic or replacement gene such as Factor VIII, U.S Serial No 08/366,851) Representative examples of cytotoxic genes include the genes which encode proteins such as ricin (Lamb et al , Eur. J. Biochem. 148.265-270, 1985), abrin (Wood et al , Eur. J. Biochem. 198:723-732, 1991 , Evensen, et al , J. of Biol. Chem. 266 6848-6852, 1991 Collins et al., J. of Biol. Chem. 265:8665-8669, 1990, Chen et al , Fed. of Eur. Biochem Soc. 309 1 15-118, 1992), diphtheria toxin (Tweten et al , J. Biol. Chem. 260 10392-10394, 1985), cholera toxin (Mekalanos et al , Nature 306 551 -557, 1983, Sanchez & Holmgren, PNAS 56 481-485, 1989), gelonin (Stirpe et al , .1. Biol. Chem. 255 6947-6953, 1980), pokeweed (Irvin, Pharmac. Ther. 21 371-387, 1983), antiviral protein (Barbieri et al , Biochem. J. 203:55-59, 1982, Irvin et al , Arch. Biochem. c - Biophy.s. 200 418-425, 1980, Irvin, Arch. Biochem. & Biophys. 769.522-528, 1975), tritin, Shigella toxin (Calderwood et al., PNAS 84.4364-4368, 1987; Jackson et al , Microb. Path. 2 147-153, 1 87), and Pseudomonas exotoxin A (Carroll and Collier, J. Biol. Chem. 262 8707-871 1 , 1987) Within further embodiments of the invention, antisense RNA may be utilized as a cytotoxic gene in order to induce a potent Class 1 restricted response Briefly, in addition to binding RNA and thereby preventing translation of a specific mRNA, high levels of specific antisense sequences may be utilized to induce the increased expression of interferons (including gamma-interferon), due to the formation of large quantities of double-stranded RNA. The increased expression of gamma interferon, in turn, boosts the expression of MHC Class I antigens Preferred antisense sequences for use in this regard include actin RNA, myosin RNA, and histone RNA Antisense RNA which forms a mismatch with actin RNA is particularly preferred Within other embodiments of the invention, antisense sequences are provided which inhibit, for example, tumor cell growth, viral replication, or a genetic disease by preventing the cellular synthesis of critical proteins needed for cell growth Examples of such antisense sequences include antisense thymidine kinase, antisense dihydrofolate reductase 99 (Maher and Dolnick, Arch. Biochem. & Biophys. 253 214-220, 1987, Bzik et al , PNAS 5-/:8360-8364, 1987), antisense HER2 (Coussens et al , Science 230 1 132-1 139, 1985), antisense ABL (Fainstein, et al , Oncogene 4 1477-1481, 1989), antisense Myc (Stanton et al , Nature 310 423-425, 1984) and antisense ras, as well as antisense sequences which block any of the enzymes in the nucleotide biosynthetic pathway Within other aspects of the invention, gene delivery vehicles are provided which direct the expression of a gene product that activates a compound with little or no cytotoxicity (i.e., a "prodrug") into a toxic product Representative examples of such gene products include varicella zoster virus thymidine kinase (VZVTK), herpes simplex virus thymidine kinase (HSVTK) (Field et al , J. Gen. Virol. -Z5? 1 15-124, 1980), and E. coll. guanine phosphoribosyl transferase (see WO 94/13304, entitled "Compositions and Methods for Utilizing Conditionally Lethal Genes," see also WO 93/10218 entitled "Vectors Including Foreign Genes and Negative Selection Markers," WO 93/01281 entitled "Cytosine Deaminase Negative Selection System for Gene Transfer Techniques and Therapies," WO 93/08843 entitled "Trapped Cells and Use Thereof as a Drug," WO 93/08844 entitled "Transformant Cells for the Prophylaxis or Treatment of Diseases Caused by Viruses, Particularly Pathogenic Retroviruses," and WO 90/07936 entitled "Recombinant Therapies for Infection and Hyperproliferative Disorders," Field et al , J. Gen. Virol. 49 1 15-124, 1980, Munir et al , Protem Engineering 7(1) 83-89, 1994, Black and Loeb, Biochem 32(43) 1 1618-1 1626, 1993) Within preferred embodiments of the invention, the gene delivery vehicle directs the expression of a gene product that activates a compound with little or no cytotoxicity into a toxic product in the presence of a pathogenic agent, thereby affecting localized therapy to the pathogenic agent (see WO 94/13304) Within one embodiment of the invention, gene delivery vehicles are provided which direct the expression of a HSVTK gene downstream, and under the transcriptional control of an HIV promoter (which is known to be transcriptionally silent except when activated by HIV tat protein) Briefly, expression of the tat gene product in human cells infected with HIV and carrying the gene delivery vehicle causes increased production of HSVTK The cells (either /// vitro or /// vivo) are then exposed to a drug such as ganciclovir, acyclovir or its analogues (FIAU, FIAC, DHPG) Such drugs are known to be phosphorylated by HSVTK (but not by cellular thymidine kinase) to their corresponding active nucleotide triphosphate forms Acyclovir and FIAU triphosphates inhibit cellular polymerases in general, leading to the specific destruction of cells expressing HSVTK in transgenic mice (see Borrelli et al , Proc. Natl. Acad. S i. (ISA 85 7572, 1988) Those cells containing the gene delivery vehicle and expressing HIV tat protein are selectively killed by the presence of a specific dose of these drugs Within further aspects of the present invention, gene delivery vehicles of the present invention may also direct the expression of one or more sequences which encode immunogenic portions of disease-associated antigens As utilized within the context of the present invention, antigens are deemed to be "disease-associated" if they are either associated with rendering a cell (or organism) diseased, or are associated with the disease-state in general but are not required or essential for rendering the cell diseased In addition, antigens are considered to be "immunogenic" if they are capable, under appropriate conditions, of causing an immune response (either cell-mediated or humoral) Immunogenic "portions" may be of variable size, but are preferably at least 9 amino acids long, and may include the entire antigen A wide variety of "disease-associated" antigens are contemplated within the scope of the present invention, including for example immunogenic, non-tumorigenic forms of altered cellular components which are normally associated with tumor cells (see U S Serial No 08/104,424) Representative examples of altered cellular components which are normally associated with tumor cells include ras (wherein is understood to refer to antigens which have been altered to be non-tumorigenic), p53 , Rb , altered protein encoded by Wilms' tumor gene, ubiquitin , mucin, protein encoded by the DCC APC, and MCC genes, as well as receptors or receptor-like structures such as neu, thyroid hormone receptor, Platelet Derived Growth Factor ("PDGF") receptor, insulin receptor, Epidermal Growth Factor ("EGF") receptor, and the Colony Stimulating Factor ("CSF") receptor "Disease-associated" antigens should also be understood to include all or portions of various eukaryotic (including for example, parasites), prokaryotic (e.g., bacterial) or viral pathogens Representative examples of viral pathogens include the Hepatitis B Virus ("HBV", see WO 93/15207) and Hepatitis C Virus ("HCV", see WO 93/15207), Human Papiloma Virus ("HPV", ee WO 92/05248, WO 90/10459, EPO 133, 123), Epstein-Barr Virus ("EBV", see EPO 173,254, JP 1, 128,788, and U S Patent Nos 4,939,088 and 5,173,414), Feline Leukemia Virus ("FeLV", see WO 93/09070, EPO 377,842, WO 90/08832, WO 93/09238), Feline Immunodeficiency Virus ("FIV", U S Patent No 5,037,753, WO 92/15684, WO 90/13573, and JP 4, 126,085), HTLV I and II, and Human Immunodeficiency Virus ("HIV", see WO 91/02805) Within other aspects of the present invention, the gene delivery vehicles described above may also direct the expression of one or more immune accessory molecules As utilized herein, the phrase "immune accessory molecules" refers to molecules which can either increase or decrease the recognition, presentation or activation of an immune response (either cell-mediated or humoral) Representative examples of immune accessory molecules include IL-1, 1L-2, IL-3, IL-4, 1L-5, IL-6, IL-7 (U S Patent No 4,965, 195), IL-8, IL-9, IL- 10, IL-1 1, IL-12 (Wolf et al , J. Immun. 46 3074, 1991 , Gubler et al., PNAS 88 4143, 1991, WO 90/05147, EPO 433,827), IL- 13 (WO 94/04680), IL-14, IL-15, GM-CSF, M-CSF-1, G- CSF, CD3 (Krissanen et al , lmmunogeneiics 26 258-266, 1987), CD8, ICAM-1 (Simmons et al , Nature 331624-627, 1988), ICAM-2 (Singer, Science 255 1671, 1992), β-microglobulin (Parnes et al , PNAS 78 2253-2257, 1981), LFA- 1 (Altmann et al , Nature 338 521, 1989), LFA3 (Wallner et al , J. Exp. Med 766(4) 923-932, 1987), HLA Class I, HLA Class II molecules B7 (Freeman et al , J. Immun. 143 2714, 1989), and B7-2 Within a preferred embodiment, the heterologous gene encodes gamma-interferon Within preferred aspects of the present invention, the gene delivery vehicles described herein may direct the expression of more than one heterologous sequence Such multiple sequences may be controlled either by a single promoter, or preferably, by additional secondary promoters (e.g., Internal Ribosome Binding Sites or "IRBS") Within preferred embodiments of the invention, a gene delivery vehicle directs the expression of heterologous sequences which act synergistically For example, within one embodiment retroviral vector constructs are provided which direct the expression of a molecule such as IL-15, IL-12, IL-2, gamma interferon, or other molecule which acts to increase cell-mediated presentation in the Tτ_ιl pathway, along with an immunogenic portion of a disease-associated antigen In such embodiments, immune presentation and processing of the disease-associated antigen will be increased due to the presence of the immune accessory molecule Within other aspects of the invention, gene delivery vehicles are provided which direct the expression of one or more heterologous sequences which encode "replacement" genes As utilized herein, it should be understood that the term "replacement genes" refers to a nucleic acid molecule which encodes a therapeutic protein that is capable of preventing, inhibiting, stabilizing or reversing an inherited or noninherited genetic defect Representative examples of such genetic defects include disorders in metabolism, immune regulation, hormonal regulation, and enzymatic or membrane associated structural function Representative examples of diseases caused by such defects include Cystic Fibrosis (due to a defect in the Cystic Fibrosis Transmembrane Conductance Regulator ("CFTCR"), see Dorin et al , Nature 326 614, ), Parkinson's Disease, Adenosine Deaminase deficiency ("ADA", Hahma et al., J. Bad. 173 3663-3672, 1991 ), β-globin disorders, Hemophilia A & B (Factor VIII- deficiencies, see Wood et al , Nature 372 330, 1984), Gaucher disease, diabetes, forms of gouty arthritis and Lesch-Nyhan disease (due to "HPRT" deficiencies, see Jolly et al , PNAS 50 477-481, 1983) Duchennes Muscular Dystrophy and Familial Hypercholesterolemia (LDL Receptor mutations, see Yamamoto et al , Cell 39 27-38, 1984) Sequences which encode the above-described heterologous genes may be readily obtained from a variety of sources For example, plasmids which contain sequences that encode immune accessory molecules may be obtained from a depository such as the American Type Culture Collection (ATCC, Rockville, Maryland), or from commercial sources such as British Bio-Technology Limited (Cowley, Oxford England) Representative sources sequences which encode the above-noted immune accessory molecules include BBG 12 (containing the GM-CSF gene coding for the mature protein of 127 amino acids), BBG 6 (which contains sequences encoding gamma interferon), ATCC No. 39656 (which contains sequences encoding TNF), ATCC No. 20663 (which contains sequences encoding alpha interferon), ATCC Nos. 31902, 3190; md 39517 (which contains sequences encoding beta interferon), ATCC No 67024 (which contains a sequence which encodes Interleukin-1), ATCC Nos. 39405, 39452, 39516, 39626 and 39673 (which contains sequences encoding Interleukin-2), ATCC Nos. 59399, 59398, and 67326 (which contain sequences encoding Interleukin-3), ATCC No. 57592 (which contains sequences encoding Interleukin-4), ATCC Nos. 59394 and 59395 (which contain sequences encoding lnterleukin-5), and ATCC No. 67153 (which contains sequences encoding lnterleukin-6). It will be evident to one of skill in the art that one may utilize either the entire sequence of the protein, or an appropriate portion thereof which encodes the biologically active portion of the protein. Alternatively, known cDNA sequences which encode cytotoxic genes or other heterologous genes may be obtained from cells which express or contain such sequences. Briefly, within one embodiment mRNA from a cell which expresses the gene of interest is reverse transcribed with reverse transcriptase using oligo dT or random primers. The single stranded cDNA may then be amplified by PCR (see U.S. Patent Nos. 4,683,202, 4,683,195 and 4,800, 159. See also PCR Technology: Principles and Applications for DNA Amplification, Eriich (ed.), Stockton Press, 1989 all of which are incorporated by reference herein in their entirety) utilizing oligonucleotide primers complementary to sequences on either side of desired sequences. In particular, a double stranded DNA is denatured by heating in the presence of heat stable Taq polymerase, sequence specific DNA primers, ATP, CTP, GTP and TTP. Double-stranded DNA is produced when synthesis is complete. This cycle may be repeated many times, resulting in a factorial amplification of the desired DNA. Sequences which encode the above-described genes may also be synthesized, for example, on an Applied Biosystems Inc. DNA synthesizer (e.g., ABI DNA synthesizer model 392 (Foster City, California)). COMPOSITIONS Within another aspect of the invention, compositions are provided comprising one or more of the above-described gene delivery vehicles, coupled to one member of a high affinity binding pair. Within other aspects of the present invention, compositions are provided comprising a gene delivery vehicle which is coupled to a high affinity binding pair, which is in turn coupled to a targeting element. Within preferred aspects of the present invention, the gene delivery vehicle is coupled to the member of the high affinity binding pair covalently, for example, by the chemical methods described above. Alternatively, a member of the high affinity binding pair may be expressed directly on the exterior or surface of the gene delivery vehicle, or, otherwise incorporated integrally into the exterior surface (e.g., contained within the envelope or lipid bilayer) of the gene delivery vehicle. Within other aspects of the present invention, any of the above compositions are provided in combination with a pharmaceutically acceptable carrier or diluent. Such pharmaceutical compositions may be prepared either as a liquid solution, or as a solid form (e.g., lyophilized) which is suspended in a solution prior to administration. In addition, the composition may be prepared with suitable carriers or diluents for topical administration, injection, or nasal, oral, vaginal, sub-lingual, inhalant or rectal administration. Pharmaceutically acceptable carriers or diluents are nontoxic to recipients at the dosages and concentrations employed. Representative examples of carriers or diluents for injectable solutions include water, isotonic saline solutions which are preferably buffered at a physiological pH (such as phosphate-buffered saline or Tris-buffered saline), mannitol, dextrose, glycerol, and ethanol, as well as polypeptides or proteins such as human serum albumin. A particularly preferred composition comprises a retroviral vector construct or recombinant viral particle in 10 mg/ml mannitol, 1 mg/ml HSA, 20 mM Tris, pH 7.2, and 150 mM NaCl. In this case, since the recombinant vector represents approximately 1 mg of material, it may be less than 1% of high molecular weight material, and less than 1/100,000 of the total material (including water). This composition is stable at -70°C for at least six months. Pharmaceutical compositions of the present invention may also additionally include factors which stimulate cell division, and hence, uptake and incorporation of a gene delivery vehicle. Representative examples include Melanocyte Stimulating Hormone (MSH), for melanomas or epidermal growth factor for breast or other epithelial carcinomas. In addition, pharmaceutical compositions of the present invention may be placed within containers or kits (e.g., one container for the coupled targeting element, and a second container for the coupled gene delivery vehicle), along with packaging material which provides instructions regarding the use of such pharmaceutical compositions. Generally, such instructions will include a tangible expression describing the reagent concentration, as well as within certain embodiments, relative amounts of excipient ingredients or diluents (e.g., water, saline or PBS) which may be necessary to reconstitute the pharmaceutical compositions. Particularly preferred methods and compositions for preserving certain of the gene delivery vehicles provided herein, such as recombinant viruses, are described in WO 94/1 1414. METHODS OF ADMINISTRATION As noted above, the present invention provides several methods for the sequential administration of coupled targeting elements and coupled gene delivery vehicles. Within one aspect of the present invention, methods are provided for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising the steps of (a) administering to a warm-blooded animal a targeting element coupled to a first molecule of a high affinity binding pair, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and (b) administering to the animal a gene delivery vehicle coupled to a second molecule of said high affinity binding pair, the second molecule being capable of specifically binding to the first high affinity molecule such that the gene delivery vehicle is targeted to the selected cell type Within one embodiment, such methods further comprise, subsequent to the step of administering a coupled targeting element and prior to the step of administering a coupled gene delivery vehicle, administering to the animal a clearing agent Within another aspect of the present invention, methods are provided for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising the steps of (a) administering to a warm-blooded animal a gene delivery vehicle coupled to a first molecule of a high affinity binding pair, and (b) administering to the warm-blooded animal a targeting element coupled to a second molecule, the coupled targeting element being capable of specifically binding to a selected cell type in the warm-blooded animal, and the second molecule being capable of specifically binding to the first high affinity molecule such that the gene delivery vehicle is targeted to the selected cell type Within various embodiments of the invention, the above-described compositions may be administered /// vivo, or ex vivo. Representative routes for in vivo administration include intraarticularly, intracranially, intradermally, intramuscularly, intraocularly, intraperitoneally, intrathecally, intravenously, subcutaneously or even directly into a tumor (for example, by stereotaxic injection) The above-described methods for sequential administration may be readily utilized for a variety of therapeutic (and prophylactic) treatments For example, within one embodiment of the invention, the methods described above may be accomplished in order to inhibit or destroy a pathogenic agent in a warm-blooded animal Such pathogenic agents include not only foreign organisms such as parasites, bacteria, and viruses, but cells which are "foreign" to the host, such as cancer or tumor cells, or other cells which have been "altered". Within a preferred embodiment of the invention, the compositions described above may be utilized in order to directly treat pathogenic agents such as a tumor, for example, by direct injection into several different locations within the body of tumor Alternatively, arteries which serve a tumor may be identified, and the compositions injected into such an artery, in order to deliver the compositions directly into the tumor. Within another embodiment, a tumor which has a necrotic center may be aspirated, and the compositions injected directly into the now empty center of the tumor. Within yet another embodiment, the above-described compositions may be directly administered to the surface of the tumor, for example, by application of a topical pharmaceutical composition containing the retroviral vector construct, or preferably, a recombinant retroviral particle. Within other aspects of the present invention, methods are provided for generating an immune response against an immunogenic portion of an antigen, in order to prevent or treat a disease (see, e.g., WO 93/10814, WO 93/15207, 29 93/09070, and WO 91/02805), for suppressing graft rejection, (see WO 94/09957), for suppressing an immune response (see WO 94/09958), and for suppressing an autoimmune response (see WO 94/09860), utilizing the above-described compositions. In addition, although warm-blooded animals (e.g., humans, macaques, horses, cows, swine, sheep, dogs, cats, chickens, rats and mice) have been exemplified in the methods described above, such methods are also readily applicable to a variety of other vertebrate animals, including, for example, fish. The following examples are offered by way of illustration, and not by way of limitation. EXAMPLE 1 CONSTRUCTION OF RETROVECTOR BACKBONES A. PREPARATION OF A RETROVIRAL VECTOR CONSTRUCT THAT DOES NOT CoNTAP AN EXTENDED PACKAGING SEQUENCE (Ψ) This example describes the construction of a retroviral vector construct using site-specific mutagenesis. Within this example, a MoMLV retroviral vector construct is prepared wherein the packaging signal "Ψ" of the retrovector is terminated at basepair 617 of SEQ ID NO: 1, thereby eliminating the ATG start of gag. Thus, no crossover can occur between the retroviral vector construct and the gag/pol expression cassette which is described below in Example 3. Briefly, pMLV-K (Miller, J. Virol 49:214-222, 1984 - an infectious clone derived from pMLV-1 Shinnick et al.. Nature, 293:543-548, 1981) is digested with Eco57\, and a 1.9kb fragment is isolated. (Eco57 \ cuts upstream from the 3' LTR, thereby removing all env coding segments from the retroviral vector construct.) The fragment is then blunt ended with T4 polymerase (New England Biolabs), and all four deoxynucleotides, and cloned into the EcoKV site of phagemid pBluescript II KS+ (Stratagene, San Diego, Calif). This procedure yields two constructs, designated pKS2+Eco57I-LTR(+) (Figure 1) and pKS2+Eco57I-LTR(-) (Figure 2), which are screened by restriction analysis. When the (+) single stranded phagemid is generated, the sense sequence of MoMLV is isolated. A new EcoRI site is then created in construct pKS2+Eco57I-LTR(+) in order to remove the ATG start codon of gag. In particular, an EcoRI site is created using the single stranded mutagenesis method of Kunkle (PNAS 52:488, 1985). pKS2+Eco57I-LTR(+) is a pBluescript™ II + phagemid (St ategene, San Diego, Calif) containing an Eco57\ fragment from pMLV-K. It includes the MoMLV LTR and downstream sequence to basepair 1378. When single stranded phagemid is generated the sense sequence of MoMLV is isolated. The oligonucleotide, 5'-GGT AAC AGT CTG GCC CGA ATT CTC AGA CAA ATA CAG (SΕQ ID NO: 2), is created and used to generate an EcoRI site at basepairs 617-622. This construct is designated pKS2+LTR-ΕcoRI (Figure 3) B SUBSTITUTION OF NONSENSE CODONS IN TILE EXTENDED PACKAGING SEQUENCE (Ψ+) This example describes modification of the extended packaging signal (Ψ+) by site-specific mutagenesis. In particular, the modification will substitute a stop codon, TAA, at the normal ATG start site of gag (position 63 1 -633 of SEQ ID NO: 1), and an additional stop codon TAG at position 637-639 of SEQ ID NO: 1 Briefly, an Eco571 - EcoRI fragment (MoMLV basepairs 7770 to approx. 1040) from pN2 (Amentano et al., J. Virol. 61 : 1647-1650, 1987) is first cloned into pBluescript II KS+ phagemid at the .S' cll and EcoRI sites (compatible). Single stranded phagemid containing antisense MoMLV sequence, is generated using helper phage M13K07 (Stratagene, San Diego, Calif). The oligonucleotide 5'-CTG TAT TTG TCT GAG AAT TAA GGC TAG ACT GTT ACC AC (SΕQ ID NO: 3) is synthesized, and utilize according to the method of Kunkle as described above, in order to modify the sequence within the Ψ region to encode stop codons at nucleotides 631-633 and 637-639. C. REMOVAL OF RETROVIRAL PACKAGING SEQUENCE DOWNSTREAM FROM THE 3' LTR Retroviral packaging sequence which is downstream from the 3' LTR is deleted essentially as described below. Briefly, pKS2+Eco57I-LTR(-) (Figure 2) is digested with Ball and Hindi, and relegated excluding the Ball to Hin i DNA which contains the packaging region of MoMLV. D. CONSTRUCTION OF VECTOR BACKBONES Constructs prepared in sections A and C above, or alternatively from sections B and C above, are combined with a plasmid vector as described below, in order to create a retrovector backbone containing all elements required in c/ ' .v, and excluding all sequences of 8 nucleic acids or more contained in the retroviral portion of the gag-pol and env expression elements (see Examples 3 and 4). 1. Parts A and C are combined as follows' The product of A is digested with Nhel and EcoRI, and a 1034 basepair fragment containing the LTR and minimal Ψ is isolated. The fragment is ligated into the product of part C at the unique (compatible) restriction sites Spe and EcoRI. The resultant construct is designated pRl (Figure 4) 2. Parts B and C are combined as follows: The product of B is digested with Nhel and EcoRI and a 1456 basepair fragment containing the LTR and modified Ψ+ region is isolated. The fragment is ligated into the product of C at the unique (compatible) restriction sites Spel and EcoRI. The resultant construct is designated pR2 (Figure 5). EXAMPLE 2 lNSERTK )N OF A GENE ( )F INTEREST INTO PR 1 AND PR2 This example describes the insertion of a gene of interest, gpl20, gp41, and rev along with a selectable marker into either pRl or pR2. Briefly, the sequence encoding gpl20, gp41 and rev is taken from construct pKTl (Figure 6; see also Chada et al., J. Vir. 67:3409- 3417, 1993); note that this vector is also referred to as N2IIIBenv. In particular, pKTl is first digested at the unique Asul site (position 5959). The ends are blunted, and an Xho I linker is ligated at that site. (New England Biolabs). The construct is then digested with Xho I, and a 4314 bp fragment containing HIV envelope (gpl20 and gp41 ), rev, SV40 early promoter and G418 resistance genes is isolated. pRl or pR2 is digested at the unique Eco Rl restriction site, blunted, and Sal I linkers (New England Biolabs) are ligated in. The 4314 bp KT1 fragment is then ligated into pRl or pR2 at the new Sal I sites, and the correct orientation is determined (see Figures 7 and 8). In both of these constructs, (pRl -HIVenv and pR2-HIVenv) the HIV genes are expressed from the MLV LTR, and G418 resistance is expressed from the SV40 promoter. EXAMPLE 3 CONSTRUCTION OF GAG-POL EXPRESSION CASSETTES A. CONSTRUCTION OF AN EXPRESSION CASSETTE BACKBONE, PHCMU-PA A vector is first created in order to form the backbone for both the gag/pol and env expression cassettes. Briefly, pBluescript SK- phagemid (Stratagene, San Diego, Calif; GenBank accession number 52324; referred to as "SK-") is digested with Spel and blunt ended with Klenow. A blunt end Dial fragment of SV40 (Fiers et al., "Complete nucleotide sequence of SV40 DNA" Nature 273: 1 13-120, 1978) from Dral (bp 2366) to Dral (bp2729) is then inserted into SK-, and a construct isolated in which the SV40 late polyadenylation signal is oriented opposite to the LacZ gene of SK-. This construct is designated SK-SV40A. A Human Cytomegalovirus Major Immediate Early Promoter ("HCMV-IE"; Boshart et al., Cell 41:521-530, 1985) (Hindi, bp 140, to Eagl, bp814) is isolated after digestion with Hindi and Eagl, and the Eagl site blunt ended. The 674 blunt ended fragment is ligated into SK-SV40A. The final construct, designated pHCMV-PA is then isolated (see Figure 1 1). This construct contains the HCMV promoter oriented in opposite orientation to the LacZ gene, and upstream from the late polyadenylation signal of SV40. B. CRΕATK >N ( )F NEW C( )DC )N.S r-( )R TI IF. 5' GAG This example describes gag/pol expression cassettes that lack non-coding sequences upstream from the gag start, thereby reducing recombination potential between the gag-pol expression element and Ψ+ sequence of a retroviral vector construct, and inhibiting co-packaging of the gag-pol expression element along with the retrovector. In order to construct such an expression cassette, 448 bp of DNA is synthesized with the following features. 5' ATATATATATATCGAT(C7-7l site)ACCATG(start codon, position 621) (SEQ ID NO 4), followed by 410 bp encoding 136+ amino acid residues using alternative codons (see Figures 9 and 10), followed by GGCGCC( ./I site)AAACCTAAAC 3' (SEQ ID NO: 5) Briefly, each of oligos 15 through 24 (set forth below in Table 1) are added to a PCR reaction tube such that the final concentration for each is 1 μM Oligos 25 and 26 are added to the tube such that the final concentration for each is 3 μM 1.2 μL of 2 5 mM stock deoxynucleotide triphosphates (dG, dA, dT, dC) are added to the tube 5 μL of 10X PCR buffer (Perkin Elmer) Water is added to a final volume of 50 μL Wax beads are added and melted over the aqueous layer at 55°C and then cooled to 22°C A top aqueous layer is added as follows 5 μL 10X PCR buffer, 7 5 μL dimethylsulfoxide, 1 5 μL Taq polymerase (Perkin- Elmer) and 36 μL water Forty cycles of PCR are then performed as follows 94°C, 30 seconds, 56°C, 30 seconds, and 72°C, 30 seconds The PCR product is stored at -20°C until assembly of the gag'pol expression cassette Table 1 SEQ. ID. Sequence No. 15 5' ATATAT ATATATCGATAC CATGGG GCA AAC CGTGACTAC CCCTCT GTCCCTCAC ACTGGC CCA A 3" 16 5'TTG ATT ATG GGC AATTCTTTC CAC GTC CTT CCA ATG GCC CAGTGTGAG GGA C 3' 17 5'AGA ATTGCCCATAATCAA AGCGTGGAC GTC AAA AAACGC AGGTGG GT G ACATTTTGT AGC GCC GAG TGG CCC 3' 18 5' AAGTTC CATCCCTAG GCC AGC CAA CATTGA ATGTGG GCC ACTCGG CGC TAC A 3' 19 5' GGC CTA GGG ATG GAA CTTTCA ATC GCG ATCTGA TTA CTC AAGTGA AA ATTA AAGTGTTCA GCC CCG GAC CCC 3' 20 5' GTG ACA ATATAA GGA ACTTGA TCG GGATGG CCGTGG GGTCCG GGG CTG AAC A 3' 21 5'AGTTCCTTATATTGTCACATC GGA GGCTCTCGCTTTCGATCC ACC ACCTTG GGTGAA ACC ATTCGTGCATCC 3' 22 5' AGG AGC GCTGGGTGG GAG GGG TGG AGGTGGTTTGGG ATG CAC GAA TGGTTTC 3' 23 5' CTC CCA CCC AGC GCTCCT AGC CTG CCCTTG GAG CCC CCA CGA AGC ACA CCA CCC AGG AGC AGCTTG TAC CCT 3' 24 5' GTTTAG GTTTGG CGC CGA GGC TGG GGG TCA GAG CAG GGT ACA AGC TGC TCCT3' 25 5' ATATATATATATCGATAC C 3' 26 5' GTTTAG GTTTGG CGCCGA GG 3' C. CREATION ( >r A NEW 3' END FC )R POL In order to prepare a gag pol expression cassette which expresses full length gag/pol, pCMVgag/pol is constructed. Briefly, MoMLV sequence from Pstl (BP567) to Nhel (bp 7847) is cloned into the Psil-Xba] sites of pUC19 (New England Biolabs). The resultant intermediate is digested with Hindlll and Xhol, and a 1008 bp fragment containing the gag leader sequence is isolated. The same intermediate is also digested with Xhol and -S'cαl, and a 4312 bp fragment containing the remaining gag and pol sequences is isolated. The two isolated fragments are then cloned into the Hindlll and Smal sites of pHCMV-PA, described above. The resultant construct, designated CMV gag/pol (Figure 12) expresses MoMLV gag and pol genes. In order to truncate the 3' end of the pol gene found in pCMV gag-pol, a 5531 basepair SnaBl - Xmal fragment containing a portion of the CMV IE promoter and all of gag- ol except the final 28 codons, is isolated from pCMV gag-pol. This fragment is cloned into the SnaBl and Xmal sites of pHCMV-PA. This construct expresses five new amino acids at the carboxy-terminus (Ser-Lys-Asn-Tyr-Pro) (SEQ ID NO: 6) (pCMV gpSma). Alternatively, these five amino acids may be eliminated by digesting pCMVgp Smal with Smal and adding an Nhel (termination codons in three phases) linker (5' - CTA GCT AGC TAG SEQ ID NO: 14; New England Biolabs) at the end of the truncated pol sequence. This construct is designated pCMV gp Nhe. Both of these constructs eliminates potential crossover between gag/pol and env expression cassettes. D. GAG-POL EXPRESSK >N CASSETTE Parts B and C from above are combined to provide an expression vector containing a CMV IE promoter, gag-pol sequence starting from the new Clal site (followed by ACC ATG and 412 bp of alternative or "wobble" gag coding sequence) and terminating at the Smal site (MoMLV position 5750) followed by an SV40 polyadenylation signal, essentially as described below. Briefly, the approximately 451 bp double stranded wobble fragment from part A is ligated into pCR™II TA cloning vector (Invitrogen Corp.). The wobble PCR product naturally contains a 3' A-overhang at each end, allowing for cloning into the 3' T-overhang of pCR™II. The 422 bp Clal -Narl wobble fragment from the pCR™II clone is removed and is ligated into the Clal (Position 679, Figure pCMV gp Sma) and Narl (Position 1585) sites of pCMVgp Smal (Part B) (or pCMV gp Nhe). (The Clal site at position 51 14 is methylated and not cut with Clal). The product of that ligation is digested with Narl, and the MLV-K Narl fragment (positions 1035 to 1378) is inserted (SEQ ID NO: 1). This construct is designated pCMVgp -X (Figure 14). EXAMPLE 4 CONSTRUCTION OF E.vr EXPRESSION CASSETTES A. CREATION OF A NEW 5' E,ιr;l RESTRICTION SITE Starting with an Eagl- EcoRI 626 bp subfragment from a 4070A amphotropic envelope (Chattopodhyay et al., J. Vir. 39:777, 1981 ; GenBank accession # MLV4070A, and #MLVΕNVC; SEQ ID NO: 12) cloned in a pBluescript II Ks+ vector (containing the start codon), site directed mutagenesis is performed upstream of the translation start site in order to change ACCATCCTCTGGACGGACATG... (SEQ ID NO: 7; positions 20 - 40 of Genebank sequence # MLVENVC) to ACCCGGCCGTGGACGGAC ATG... (SEQ ID NO: 8) and create a new Eagl site at position 23. This modification allows cloning of the amphotropic envelope sequence into an expression vector eliminating upstream 4070A sequence homologous to the gag-pol expression element as described in Example 2A. B. CREATION OF A NEW 3' END FOR ENV A new 3' end of the envelope expression element is created by terminating the sequence which encodes the R-peptide downstream from the end of the transmembrane region (pl5E). Briefly, construct pHCMV-PA, described above, is first modified by digestion with NotI (position 1097), blunted and relegated to obliterate the overlapping Bluescript Eagl site at the same position. pCMV Envam-Eag-X-less is then constructed by digesting the modified pHCMV-PA with Eagl (position 671 and Smal (position 712) and ligating in two fragments. The first is an Eagl-Ncol fragment from 4070A (positions 1-1455) (SEQ ID NO: 12). The second is an MLV-K envelope fragment, Ncol - Pvull (positions 7227-7747) (SEQ ID NO: 12). The resultant construct from the three-way ligation contains the HCMV promoter followed by the SU (GP70) coding sequence of the 4070A envelope, the TM (pl5e) coding sequence of MoMLV, and sequence encoding 8 residues of the R-peptide. In addition, this envelope expression cassette (pCMV Env am-Eag-X-less) (Figure 18) shares no sequence with crossless retrovector backbones described in Example 1. C. ENVELOPE EXPRESSION ELEMENT Parts A and B from above are combined to complete an amphotropic expression element containing the CMV promoter, 4070A SU, MoMLV TM and SV40 polyadenylation signal in a Bluescript SK- plasmid vector. This construct is called pCMVenv- X (Figure 15). Briefly, the construct described in part A with a new Eagl restriction site is digested with Eα^l and Xhol, and a 571 bp fragment is isolated. pCMV Εnvam-Εag-X-less (from part B) is digested with Kp l and Eagl and the 695 bp fragment is reserved. pCMV Εnvam-Εag-X-less (from part B) is digested with Kpnl and Xhol and the 4649 bp fragment is reserved. These two fragments are ligated together along with the 571 bp Eα^I to Xhol fragment digested from the PCR construct from part A. pCMVenv-X shares no sequence with crossless retrovector backbones nor the gag-pol expression element pCMVgp-X. EXAMPLE 5 FUNCTIONALITY TESTS FOR GAG-POL AND EΛ r ι ' EXPRESSION CASSETTES Rapid tests have been developed in order to ensure that the gag-pol and env expression cassettes are biologically active. The materials for these tests consist of a cell line used for transient expression (typically 293 cells, ATCC #CRL 1573), a target cell line sensitive to infection (typically HT 1080 cells, ATCC #CCL 121 ) and either pRgpNeo (Figure 16) or pLARNL (Emi et al., J. Virol 65: 1202-1207, 1991) The two later plasmids express rescuable retrovectors that confer G418 resistance and also express gag-pol, in the case of RgpNeo or env, in the case of pLARNL For convenience, the organization of RgpNeo (Figure 16) is set forth below In order to test expression cassettes such as pCMVgp-X for functionality of gag/pol, the plasmid is co-transfected with pLARNL at a 1 : 1 ratio into 293 cells After 12 hours, the media is replaced with normal growth media After an additional 24 hours, supernatant fluid is removed from the 293 cells, filtered through a 0.45 μm filter, and placed on HT 1080 target cells Twenty-four hours after that treatment, the media is replaced with growth media containing 800 ug/ml G418 G418 resistant colonies are scored after one week. The positive appearance of colonies indicates that all elements are functional and active in the original co-transfection. For convenience, the organization of RgpNeo (Figure 16) is set forth below: Position 1 = left end of 5' LTR; Positions 1 -6320 = MoMLV sequence from 5'LTR to Sea 1 restriction site; Positions 6321 - 6675 = SV40 early promoter; Positions 6676-8001 = Neo resistance gene from Tn 5 (including prokaryotic promoter); and Positions 8002 - 8606 = pBR origin of replication EXAMPLE 6 PACKAGING CELL LINE AND PRODUCER CELL LINE DEVELOPMENT This example describes the production of packing and producer cell lines utilizing the above described retroviral vector constructs, gag/pol expression cassettes, and env expression cassettes, which preclude the formation of replication competent virus. Briefly, for amphotropic MoMLV-based retroviral vector constructs, a parent cell line is selected which lacks sequences which are homologous to Murine Leukemia Viruses, such as the dog cell line D-17 (ATCC No CCL 183) The gag/pol expression cassettes are then introduced into the cell by electroporation, along with a selectable marker plasmid such as DHFR (Simonsen et al., PNAS 50:2495-2499, 1983). Resistant colonies are then selected, expanded in 6 well plates to confluency, and assayed for expression of gag/pol by Western Blots. Clones are also screened for the production of high titer vector particles after transduction with pLARNL. The highest titer clones are then electroporated with an env expression cassette and a selectable marker plasmid such as hygromycin (see Gritz and Davies, Gene 25: 179-188, 1983). Resistant colonies are selected, expanded in 6 well plates to confluency, and assayed for expression of env by Western Blots. Clones are also screened for the production of high titer vector particles after transduction with a retroviral vector construct. Resultant packaging cell lines may be stored in liquid Nitrogen at 10 x 10° cells per vial, in DMEM containing 10% irradiated Fetal Bovine Serum, and 8% DMSO. Further testing may be accomplished in order to confirm sterility, and lack of helper virus production. Preferably, both an S+L- assay and a Mus duniii marker rescue assay should be performed in order to confirm a lack of helper virus production. In order to construct a producer cell line, retroviral vector construct as described above in Example 1 is electroporated into a xenotropic packaging cell line made utilizing the methods described above. After 24-48 hours, supernatant fluid is removed from the xenotropic packaging cell line, and utilized to transduce a second packaging cell line, thereby creating the final producer cell line. EXAMPLE 7 HELPER DETECTION ASSAY COCULTIVATION, AND MARKER RESCUE This example describes a sensitive assay for the detection of replication competent retrovirus ("RCR"). Briefly, 5 x 10^ vector-producing cells are cocultivated with an equal number of Mus duniii cells (Lander and Chattopadhyay, J. Virol. 52:695, 1984). Mus dunni cells are particularly preferred for helper virus detection because they are sensitive to nearly all murine leukemia-related viruses, and contain no known endogenous viruses. At three, six, and nine days after the initial culture, the cells are split approximately 1 to 10, and 5 x 10^ fresh Mus dunni cells are added. Fifteen days after the initial cocultivation of Mus dunni cells with the vector-producing cells, supernatant fluid is removed from cultures, filtered through a 0.45 μm filter, and subjected to a marker rescue assay. Briefly, culture fluid is removed from a MdH tester cell line (Mus dunni cells containing pLHL (a hygromycin resistance marker retroviral vector; see Palmer et al., PNAS 54(4)1055-1059, 1987) and replaced with the culture fluid to be tested. Polybrene is added to a final concentration of 4 μg/ml. On day 2, medium is removed and replaced with 2 ml of fresh DMEM containing 10% Fetal Calf Serum. On day 3, supernatant fluid is removed, filtered, and transferred to HT1080 cells. Polybrene is added to a final concentration of 4μg/ml. On day 4, medium in the HT1080 cells is replaced with fresh DMEM containing 10% Fetal Calf Serum, and 100 μg/ml hygromycin. Selection is continued on days 5 through 20 until hygromycin resistant colonies can be scored, and all negative controls (e.g., mock infected MdH cells) are dead. EXAMPLE 8 RETROVIRAL VECTOR- A VIDIN COUPLED GENE DELIVERY VEHICLES, AND MELANOCYTE STIMULATING HORMONE-BIOTIN COUPLED TARGETING ELEMENTS The following example describes the use of the coupled targeting element melanocyte stimulating hormone-biotin to target the coupled retroviral vector particle-biotin to a specific cell type. Generally, biotinylated melanocyte stimulating hormone (MSH) is first injected into the patient. After a period of time (up to 3 days) after which non-specific binding has decayed and only specific ligand complexes remain, a vector expressing avidin on its surface is injected. The high affinity of avidin for biotin focuses the vector to the target tissue. Briefly, melanocyte-stimulati g hormone (MSH) is a 13 amino acid peptide that is specifically recognized by a receptor on melanocytes. MSH has a receptor affinity (K D ) in the range of 10 "8 M. A. CONSTRUCTION OF PCMV-ENV 1 - pCMV-env CC0 is created by inserting the Xbal-Nhel fragment of MoMLV (bp 5766 through bp 7845 of MoMLV) into pCMV-PA (example 3 A) expression vector. Briefly the Xbal-Nhel envelope fragment is isolated from pMLV-K (Miller et al., J. Vir. 49:214- 222,1988) on an agarose gel. The fragment is then blunt-ended with T4 polymerase using standard methods, ligated into pCMV-PA (example 3), and digested at the EcoRV and Smal sites. The product in the correct orientation has a CMVIE promoter followed by the complete ecotropic envelope coding sequence and an SV40 polyadenylation signal. B. CREATION OF ΛVIDΠM-ENVELOPE CHIMERA A portion of avidin DNA (GenBank # CHKAVIR) from bp 1 16 through bp 499 is incorporated into the MoMLV ecotropic envelope construct pCMV-env *300 . Briefly, the following oligonucleotide is generated as follows: 5'-GCT AGA ATA TCA AGC CAG AAA GTG CTC GCT GAC TGG GAA ATG GAC CAACGATCTGGGCTC CAA CAT GAC CATCGG GGC TGT GAA CAGCAGAGG TGAATTCACCCTGCGCACACAGAAGGAGCGGTGCAACAC-3' (Sequence I.D. No. 27) The oligonucleotide is used to modify single stranded pCMV-env eco by the method of Kunkle (PNAS 52:488, 1985). This modification replaces a portion of the variable A region of envelope (Battini et al., J. Virol 66: 1468-1475, 1992) with the sequence of the oligonucleotide. The product is then digested with EcoRI and partially digested with Fspl. The EcoRI-FspI fragment of avidin (bp 198 through bp 485) is ligated into the vector. The final product is a plasmid containing CMV promoter, hybrid eco-avidin envelope and SV40 polyadenylation signal, called pCMV-env ec °- avιdιn . C. BlOTINYLATED MSH The MSH peptide S-Y-S-M-E-H-F-R-W-G-L-P-V-NH2 (Sequence I.D. No. 28) is synthesized (Chiron Corp., Emeryville, CA), and biotinylated with NHS-Biotin (Pierce) according to the manufacturer's instructions. D. GENERATION OF MARKER RETROVECTOR DISPLAYING AVIDIN The beta galactosidase encoding marker retrovector, CBβ-gal is cotransfected into cell line 293 2-3 (WO 92/05266) along with pCMV-env e °- a idin . Alternatively, equivalent vectors encoding luciferase, green fluorescent protein (GFP) or other markers can be used. Clones are selected (with G418) and screened for high production of RNA containing particles and screened for surface expression of avidin using 3 H-biotin binding. Vector particles containing avidin are tested utilizing , C-biotin (Amersham) and a sucrose gradient. E. IN ΠTR TARGETING Human melanoma cells, DM252, DM6, DM92 are grown in appropriate medium. The specificity of biotinylated MSH binding to target cells is tested by addition of avidin-fluorescein and fluorescence microscopy. Transduction of eco-avidin CBβ-gal is tested either by staining or by G418 selection (see WO 94/21792), and the efficiency of tranduction compared to non-melanoma cells such as HT1080 human fibrosarcoma cells. F. 7λ' 17 TARGETING Nude mice are implanted with one or more of the following human melanoma cell lines: DM252, DM6, DM92 (.see WO 94/21792) in the peritoneal cavity. Targeting is determined by first injecting biotin-MSH into the mouse, followed by injection of 10 5 -10 8 colony forming units eco-avidin CBβ-gal retrovectors. Targeting is assessed by subsequently dissecting the melanoma tissue, and staining for β-gal, or assaying for luciferase activity in the melanoma and mouse tissue. As a control, the same vectors encapsidated in the pCMV- env eco transfection of 293-2-3 cells, and with no added envelope plasmids, are injected into mice in parallel, and the tissues of these mice are assayed. EXAMPLE 9 CONJUGATION OF CARBOXYPEPTIDASE A WITH LACTOSE A. PREPARATION OF OXIDIZED LACTOSE A solution of 0.01 M Na borate pH 4.0, with 0.1 M Na m-periodate (Sigma Chemical Company, St. Louis) and 0.1 M in lactose is prepared and incubated 1 hour at room temperature in the dark (C.J. Sanderson and D.V. Wilson, Immunology 20: 1061-1065, 1971). The solution is then adjusted with 0.2 M Na phosphate buffer to pH 7. B. CONJUGATION WITH CPA 10 mg of bovine pancreatic carboxypeptidase A (CpA) (Sigma Chemical, St. Louis, MO) is dialyzed in a large excess of 0. 1 M Na phosphate buffer overnight. The solution is concentrated to 2 ml (5 mg/ml) in Centricon 10,000 dt cutoff centrifugal ultrafiltration units, according to manufacturer's directions (Amicon). Lactose is added to the CpA solution at a 1000-fold molar excess (285 mmoles), and incubated at room temperature for one hour. The reaction is terminated by the reduction of the Schiffs base by the addition of cyanoborohydride (Sigma) (Borch et al., J. Am. Chem. Sac. 93: 2897-2904 (1971) and Fagnani et al., Cancer Research 50: 3638-3645 ( 1990)) at a ratio of 1 :5 relative to the lactose, and incubating another 2 hours with stirring. The conjugate is dialyzed against phosphate buffered saline pH 7.5 and stored at 4 C prior to injection. C. PREPARATION OF SINDBIS VECTOR PARTICLES CARRYING THE β- GALACTOSIDASE GENE Preparation of Sindbis vector particles carrying the β-galactosidase gene involves four primary steps: (1 ) construction of a Sindbis vector; (2) insertion of the β-galactosidase gene into the Sindbis vector; (3) packaging of the Sindbis/β-galactosidase vector by transfection/ infection of a cell line expressing the Sindbis viais structural proteins; and (4) purification of Sindbis vector particles. Other marker genes such as luciferase or green fluorescent protein (GFP) can be used in an equivalent fashion, except for the assay of the gene product. Briefly, the configuration of Sindbis is that of a replacement vector, wherein the heterologous genetic material is substituted for the viral structural genes The remaining portion of the viral genome is unmodified Thus, on a linear map, the expression vector is comprised of the following ordered elements Sindbis nonstructural genes, Sindbis junction region, β-galactosidase gene, 40 3' end Sindbis nucleotides, a consecutive tract of 40 dA:dT residues, and a restriction endonuclease recognition sequence which is unique to the vector construction The signal for genome packaging is contained within the nonstructural protein region The construction of the basic Sindbis vector from a genomic Sindbis virus cDNA clone is described in Example 2, WO 94/10469 Briefly, construction of the Sindbis β- galactosidase vector is performed by assembling together components of 3 independent plasmids, pSKIIS'SI M and pKSH3'SlN, and pSV-β-galactosidase, Promega (Madison, WI) The β-galactosidase gene is first inserted into the pKSII3'SIN plasmid between the Hind III and Bam HI sites The β-galactosidase gene is then isolated from the pSV-β-galactosidase plasmid by digestion with Bam HI and Hind III, and electrophoresed on a 1% agarose/TBE gel An approximately 3,737 bp fragment is then excised from the gel, and purified with Gene Clean II kit (Bio 101, San Diego, CA) Insertion into pKS3'SIN is then accomplished by ligation of the 3737 bp β-galactosidase fragment with a gel purified 3008 bp fragment resulting from digestion with Bam HI and Hind III and treatment with CIAP of pKSIB'SIN. This construction is designated as pKSII3'SιN-β-Gal Final assembly of the Sindbis β-galactosidase vector is accomplished by first digesting pSK5'SIN with Xho I and Sac I, then treating with CIAP, and gel purifying the large 10,533 bp fragment The pSK5'SIN 10,533 bp fragment is then ligated together with the 2854 bp small fragment resulting from digestion of pKSID'SIN-β-Gal with Xho I and Sac I This construction contains the entire Sindbis nonstructural gene coding region, and 3' viral elements necessary for genome replication, the β-galactosidase gene is placed between these two viral 5' and 3' elements This vector is designated as pSKSINBV-β-Gal In the application described above, the pSKSINBV-β-Gal vector is defective and is unable to complete a full infection cycle including cell lysis when introduced to monolayers known to support the permissive infection of Sindbis virus In order to construct a Sindbis vector particle which is capable of expressing the β-galactosidase gene after infection of cells permissive for supporting infection characteristic of wild type Sindbis virus, vector RNA from the pSKSINBV-β-Gal clone is first transcribed vitro, then transfected onto a cell line which expresses the Sindbis structural proteins The pSKSINBV-β-Gal clone is linearized by digestion with Sac I, and the 3' overhang ends generated by digestion with the enzyme are made blunt by inclusion of the T4 DNA polymerase enzyme from E. co during the last 15 minutes of digestion RNA corresponding to the Sindbis-β-Gal vector is transcribed /// vitro from purified linearized pSKSINBV-β-Gal DNA, using the mMessage mMachine kit (Ambion Inc , Austin TX) according to the directions of the supplier Packaging of the Sindbis vector is accomplished by transfection of the m vitro transcribed Sindbis-β-Gal RNA with Lipofectin (Gibco-BRL, Gaithersberg, MD) onto cells which express the Sindbis structural proteins These cells are known as Sindbis vector packaging cell lines, and their construction is described in Example 7 of WO 94/10469 The Sindbis vector packaging cell lines can be derived from several possible hosts, including for example, mosquito, quail, and hamster cells In order to generate a high titer preparation of the Sindbis-β-Gal vector particle, supernatants from the transfected Sindbis vector packaging cell lines are harvested at 24 hours post transfection, and used to infect fresh Sindbis packaging cell line monolayers One ml of transfection supernatant is used per 10 cm plate, which contain, typically, 5 X 10 6 cells Packaged Sindbis-β-Gal vector particles are purified and concentrated from the infected Sindbis vector packaging cells at 48 hours post infection, or when the cells demonstrate substantial cytopathic effects (CPE) The vector particle is purified and concentrated by the following steps ( 1 ) removal of cell debris by centrifugation at 1000 g for 15 min , (2) two-fold purification by gradient centrifugation through linear 15-35% potassium tartrate gradients in phosphate-buffered saline lacking calcium, for 12 hours at 24,000 r p m ; and (3) dialysis overnight at 4 C C, with 12,000 MW cut-off bags, against a buffer comprised of 10 mM HEPES and 100 mM NaCl, pH 7 4 Wild type Sindbis virus particles purified in this manner typically have titers of 1 x 10 1 (> to 1 x 10" PFU/ml D SYNTHESIS OF PEPTIDE ANALOG CYS-PIIE-VAI P -(Q)PHE The transitional state analog inhibitor, [[L-Cysteinyl-L-phenylalanyl-L-valinyl- 1-aminoethyl] hydroxyphosphinyl]-L-phenylalanine, is synthesized from commercially available reagents as described in Hanson et al (Hanson et al , Biochemistry 28 6294-6305 (1989) or Kaplan and Bartlett (Kaplan and Bartlett, Biochemistry 30 8165-8170 (1991) E CONTUGATION OF SINDBIS ' I P A HIGH AFFINITY MOLECULE 1 Reaction of Sindbis Vector with SulfoSMCC Purified Sindbis vector is dialysed in 0 1 M Na phosphate buffer pH 7 5 Sulfosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SulfoSMCC) (Pierce, Rockford, IL) is dissolved in water (Carisson et al , Biochem. .1 173: 723-737 ( 1978) and Hashida et al , J. Appl. Biochem. 6 :56- 63 (1984)) Sindbis reactor is added to the SulfoSMCC solution, and incubated overnight at 4 °C on a rocker. The virus is then separated from the cross-linking agent by dialysis in degassed 0.1 M Na phosphate buffer, 1 mM EDTA pH 7.0. 2. Reaction of the Peptide Derivative with the Sindbis Vector: The peptide analog described in Section D above is reduced in 10 mM dithiothreitol, and desalted in degassed 0.1 M Na phosphate buffer, 1 mM EDTA pH 7.0 on a P6 column (BioRad, Melville, NY). The peptide is then added to the Sindbis vector conjugate and allowed to react for one hour at 4°C on a rocker. The virus is separated from the unconjugated peptide by dialysis in phosphate buffered saline. F. TARGETING β-GAL EXPRESSION TO THE LIVER IN RATS A solution containing 100 μg of the carboxypeptidase A conjugate is injected into the tail vein of adult male Sprague-Dawley rats. After 24 hours, the rats are anesthetized with ketamine ( 1 10 mg/kg, ip) and 10 7 units of the Sindbis vector are injected into the hepatic portal vein. After 24 or 48 hours, the rat is dissected and tissue sections are examined for βgal expression or the expression of other marker genes. The results are compared to those obtained with unmodified control Sindbis vectors. EXAMPLE 10 TARGETING POLYCATION-DNA COMPLEXES TO THE LIVER WITH C Y ' R )STATIN AND PΛPAIN A. CONJUGATION OF TRANSFERRIN WITH CYSTATIN Cystatin and transferrin are obtained commercially (Sigma). Briefly, the transferrin and cystatin are combined in a 1 : 1 molar ratio (approx. 5: 1 w/w) at total of 30 mg/ml in water and dialyzed in 0.001 M Na phosphate pH 7.5. Solid l-ethyl-3-(3- dimethylaminopropyl) carbodiimide HCI (Pierce) is added to a final concentration of 20 mM. The reaction is incubated at room temperature (approx. 22°C) on a rocker and quenched after 16 hours by the addition of solid Na acetate to 200 mM. This reaction is described in more detail in M.R. Mauk and A.G. Mauk, Eur. .1. Biochem. 186: 473-486 (1989). The reaction is diluted to 4 mg/ml and dialyzed into phosphate buffered saline. The extent of the reaction is checked by SDS gel electrophoresis. B. CONJUGATION OF PAPAIN TO POI.YCATION-DNA COMPLEX, AND PREPARATION OF PAPAIN-POLYCATION-DNA/βGAL EXPRESSION REPORTER PLASMID MIXTURES The papain-polycation conjugate is formed by mixing commercially available papain (Sigma Chemical Co., St. Louis, MO) with poly-L-lysine, Mr = 41,000 dt (Sigma) at a 1 : 1 weight ratio in 5 ml deionized water, pH 7.4. The reactants are conjugated with 1 -ethyl- 3-(3-dimethylaminopropyl) carbodiimide HC1 (Pierce) in a 140 fold excess over papain and stirred 16 hours at 25 C. The reaction mixture is then dialyzed against deionized water at 4 C for 72 hours (G.Y. Wu, P. Zhan, LL. Sze, A.R. Rosenberg, and C.H. Wu, J. Biol. Chem. 269: 11542-11546 (1994)). The extent of cross-linking is determined by SDS gel electrophoresis. A CMV promoter, β-gal expression vector designated pcDNA3 (Invitrogen) is mixed at a 1 : 1.3 w/w ratio of plasmid to polylysine conjugate in 150 mM NaCl, 20 mM HEPES pH 7.4, at 4 μg plasmid/ml and incubated at room temperature for 30 minutes (Wagner et al., Proc. Natl. Acad. Sci. 88: 4255-4259 ( 1991 )). Other marker plasmids (e.g., luciferase) can also be used. The transferrin receptor is elevated in most tumor types. Thus, nude mice bearing several types of human tumor xenografts either in the peritoneum or as liver metastases are injected with 100 ng to 1 mg of conjugated transferrin-cystatin, intraperitoneally, or in the tail vein, respectively. At 2 hours to 21 days later, the DNA complex carrying 100 ng to 100 μg of DNA is injected into the same site, or into the hepatic portal vein. After 24-72 hours, mice are dissected and tumors and tissues tested for marker gene activity in order to determine targeting of the polycation-DNA complex. EXAMPLE 1 1 TARGETING WITH ECOTROPIC ENVELOPE FUSED WITH AVIDIN CONSTRUCTION OF RXEN AND RSEN The first retroviral vector, ReNeo, designed as a base for modifying the ecotropic envelope, was made by replacing the β galactosidase gene of the BAG vector (Figure 19) (Price et al., PNAS 84: \ 56- \ 60, 1987) with the ecotropic envelope gene of MLV- K (Miller et al., J. Virol. 49:214, 1984). The BAG vector consists of one murine Moloney leukemia virus LTR, β galactosidase gene, SV40 promoter/enhancer, neomycin kanamycin resistance gene, and the pBR322 origin of replication. The β galactosidase gene was removed by digesting the BAG vector with BamHI and religating it, to make the intermediate construct, BAGΔB (Figure 20). The ecotropic envelope gene was taken from pMLV-K (Figure 21) by digestion with Xbal and Nhel and ligated into the Xbal site of pUC18 in such a way as to put the 5' end of envelope next to the Pstl site of the polylinker and the 3' end near the BamHI site (Figure 22). The sequence of the envelope insert of this intermediate vector, pNAGl, was verified by standard DNA sequencing methods. The ecotropic envelope was removed from pNAGl by partial digestion with BamHI and complete digestion with Pstl. The BAGΔB vector was digested with EcoRI and BamHI for one fragment of a three piece ligation, and the smaller, 1600 bp fragment was isolated. The BAGΔB vector was then digested with EcoRI and Pstl and the larger, 2000 bp fragment was isolated. The ecotropic envelope Pstl-BamHI fragment was ligated with the two BAGΔB fragments, BamHl-EcoRl and EcoKl-Psfl to make ReNeo (Figure 23). The extended packaging sequence was taken from the KT1 vector (Figure 24) by digestion with Aatll and Xhol, isolating the 600 bp fragment. This was ligated to ReNeo in a three piece ligation, <7/II--9røHI, 5 Kb fragment and Dralll-Sall, 700 bp fragment. The resulting retroviral vector, RXEN, (Figure 25) contains the extended packaging sequence as well as the rest of the features of ReNeo. The envelope gene in ReNeo and RXEN was removed without the native splice acceptor from Moloney MLV. There is a strong splice donor in the extended packaging sequence of RXEN, and only a cryptic splice acceptor upstream of the envelope gene. This may impair the efficiency of envelope mRNA production by ReNeo and RXEN by allowing the coding sequence to be spliced out of the transcript. The native splice acceptor of the Moloney envelope was excised from MLV-K as a 400 bp Xba I fragment and inserted upstream of the envelope gene of RXEN, partially digested with Xbal, to make RSEN (Figure 26). TABLE 1 SEQUENCES OF PRIMERS FOR AVIDIN-ENVELOPE CHIMERA CONSTRUCTION Primer Sequence Seq. ID No. A CTTGTCTGCTGCAGGTCGACTCTAGACTGACATG 29 B AGAGGGGTCAGTACTGCCAGAAAGTGCTCG 30 C CGAGCACTTTCTGGCAGTACTGACCCCTCT 31 D CTGCGCACACAGAAGGAGGCTTCGCCCGGCTCC 32 E GGAGCCGGGCGAAGCCTCCTTCTGTGTGCGCAG 33 F CATTCCACAGCGGTCGACCCGGGCGGATCC 34 G TTTGAGAGATCCAACGCCAGAAAGTGCTCG 35 H CGAGCACTTTCTGGCGTTGGATCTCTCAAA 36 I CTGCGCACACAGAAGGAGCGACACAAAAGAGAA 37 J TTCTCTTTTGTGTCGCTCCTTCTGTGTGCGCAG 38 K ATGTTAGCCCACCATGGTGGCTCAGCCAGAAAGTGCTCG 39 L CGAGCACTTTCTGGCTGAGCCACCATGGTGGGCTAACAT 40 M CTGCGCACACAGAAGGAGGGTGGCTCACCAGGCTCTTCCAGAGACTCCGAAGAA 41 N TTCTTCGGAGTCTCTGGAAGAGCCTGGTGAGCCACCCTCCTTCTGTGTGCGCAG 42 P GCTGTCCAGGTATGCGGTGGCTCAGCCAGAAAGTGCTCG 43 Q CGAGCACTTTCTGGCTGAGCCACCGCATACCTGGACAGC 44 R CTGCGCACACAGAAGGAGGGTGGCTCAGGTGGCTCATGCAACCCCTTAGTT 45 S AACTAAGGGGTTGCATGAGCCACCTGAGCCACCCTCCTTCTGTGTGCGCAG 46 TABLE II INSERTION OF AVIDIN INTO MOLONEY ECOTROPIC ENVELOPE BY DOUBLE OVERLAP PCR Fusion Point Template Primer 1 * Primer 2* Product Amino ReNeo** A C AC Amino Avidin B E BE Amino ReNeo D F DF Amino AC and BE A E AE Amino AE and DF A F Final Insert Var.A ReNeo A L AL Var. A Avidin K N KN Var. A ReNeo M F MF Var. A AL and KN A N AN Var. A AN and MF A F Final Insert Var. B ReNeo A Q AQ Var. B Avidin P S PS Var. B ReNeo R F RF Var. B AQ and PS A S AS Var. B AS and RF A F Final Insert Carboxyl ReNeo A H AH Carboxyl Avidin G J GJ Carboxyl ReNeo 1 F IF Carboxyl AH and GJ A J AJ Carboxyl AJ and IF A F Final Insert * Primer Sequences are shown in Table 1 above. * Template Sequences are shown in Figures 27, 28A and 28B. B. CONSTRUCTION OF AVIDIN CHIMERAE BY PCR The avidin envelope chimerae were constructed by double overlap PCR using ReNeo and chicken avidin cDNA as templates (Horton et al., Bioiechniques 5:528-535, 1990). The primers A and F in Table I correspond to outside sequences flanking the envelope gene and the remaining 16 primers are designed in sets of four for the insertion of avidin into four differents sites in the envelope gene. The four sites used for fusion with avidin were: 1) the amino terminus, between thr33 and ala34; 2) the variable region A, replacing the sequence from gly85 through serl 1 1 and changing cysl 14 and cysl 18 each to serine; 3) the variable region B, replacing sequence from Iys210 through trp214. The PCR reactions were carried out as indicated in Table II on template sequences listed in Figures 27, 28A and 28B, as recommended by the manufacturer's instructions using a GeneAmp PCR kit (Perkin Elmer/Cetus). The final chimeric PCR products containing avidin inserted at the specified sites were each cloned into the vector, pCRII according to the manufacturer's instruction using the TA Cloning kit (Invitrogen, San Diego, CA). The sequences of the avidin inserts and the envelope region flanking them were verified by standard DNA sequencing methods. The clones that were found to be correct and were used in all further constructions were: pCRII/N5 (Figure 29) for the amino terminal fusion, pCRII/Al (Figure 30) for the variable region A fusion, pCRII/B 14 (Figure 31) for the variable region B fusion, and pCRII/C8 (Figure 32) for the carboxyl terminal fusion. C CONSTRUCTION OF RXEN/AVIDIN RETROVIRAL VECTORS The avidin-containing regions of the pCRII clones were removed by digestion with appropriate restriction enzymes and inserted into the corresponding sites of RXEN. Three of the four avidin fusions, pCRH/N5, pCRII/A l and pCRII/B 14, were cloned into RXEN by ligation of each Scal-Dralll, 1. 1 Kb fragment to RXEN cut with Seal and Drain to make RXEN/N5 (Figure 33), RXEN/A 1 (Figure 34), and RXEN/B 14 (Figure 35). The carboxy terminal avidin fusion pCRII/C8 was cut with Dralll and Clal, 1.5 Kb, and ligated to RXEN, partially digested with Clal and completely with Dralll, 5.0 Kb to make RXEN/C8 (Figure 36). D. TRANSDUCTION OF PACKAGING CELL LINES WITH RXEN/AVIDIN RETROVIRAL VECTORS The retroviral vectors containing chimeric avidin-envelope genes were introduced into the packaging cell lines, 293 2-3 and HX (WO 92/05266) and GP+E (Markowitz et al., J. Virol. 62: 1 120-1 124, 1988) by G pseudotyping (Burns et al., PNAS 90:8033-8037, 1993). This method consists of cotransfection of 293 2-3 with 10 μg of each of RXEN, RXEN/N5, RXEN/A1 , RXEN/B 14, and RXEN/C8 retroviral vectors with 10 μg of the VSV G protein vector, MLPG by CaPθ4 transfection with the ProFection kit according to the manufacturer's instructions (Promega, Madison, WI). This was followed by transduction of 293 2-3, HX and GP+E each with the resulting vector-containing supernatants. These cells were subjected to selection with geneticin and the resulting pooled transductants were raised to confluency. The supernatants of these cell lines were harvested, passed through 0.45 μm filters and stored at -80°C in aliquots until use. E. IN VITRO TARGETING ASSAY USING BIOTINYLATED LIGANDS Target cells, either HCT1 16 human colon carcinoma cells (ATCC No. CCL 247) or murine SC- 1 cells (ATCC No. CRL 1404), were seeded at 1 x 10 5 cells per well of a six well plate in two ml of fresh DMEM containing 10% Fetal Calf Serum (FCS). On day 2, plates were removed from the 37°C. incubator and set on an ice bed for fifteen minutes prior to addition of biotinylated ligand, to slow cellular metabolism and reduce surface membrane capping. Each biotin conjugated reagent was then added to a single culture well in the following concentrations: Transferrin-biotin, 5 mg/well; Low Density Lipoprotein-biotin, 2.5 mg/well; Wheat germ Agglutinin-biotin, 2 mg/well; Phytohemagglutinin-L-biotin, 2 mg/well; or Concanavalin-A-biotin, 2 mg/well This mixture was incubated on ice for thirty minutes, then each well was washed twice with cold DMEM media and brought to one ml with DMEM plus 10% FCS. Retrovector with avidin fused to envelope: RXEN, RXEN/N5, RXEN/B14, RXEN/C8, and RXEN/A1 , packaged in HX, GP+E and 293 2-3 packaging cell lines were collected from the supernatant of 24 hour confluent packaging cell line cultures, and filtered through a 0.45μm filter. Equal volumes of this material are added to each culture well, and the final volume brought to 2 ml with DMEM plus 10% FCS. Control wells included target cells with no biotinylated ligand and no retroviral vector, and target cells with retroviral vector only. Polybrene was added to each well at a final concentration of 4 mg/ml. Plates were held on ice for another thirty minutes, then incubated at 37°C. On day 4 post-transfection, medium on the HCT1 16 cells was replaced with fresh DMEM containing 10% FCS and 400 mg/ml G418. Selection was continued from days 5 through 14 until G418 resistant colonies could be detected and scored, and until all cells in control wells lackin" retroviral vector were dead From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANTS: Jolly, Douglas, J. Barber, Jack R. Respess. James G. Moore, Margaret (n) TITLE OF INVENTION: Compositions and Methods for Targeting Gene Delivery Vehicles (in) NUMBER OF SEQUENCES: 26 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Seed & Berry (B) STREET: 6300 Columbia Center; 701 Fifth Avenue (C) CITY: Seattle (D) STATE: Washington (E) COUNTRY: USA (F) ZIP: 98104 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE- Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentin Release #1.0, Version #1.25 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: US (B) FILING DATE: 15-MAY-1995 (C) CLASSIFICATION: (vm) ATTORNEY/AGENT INFORMATION: (A) NAME: McMasters. David D. (B) REGISTRATION NUMBER: 33.963 (C) REFERENCE/DOCKET NUMBER: 930049.431PC (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: (206)622-4900 (B) TELEFAX: (206)682-6031 (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8332 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:l: GCGCCAGTCC TCCGATTGAC TGAGTCGCCC GGGTACCCGT GTATCCAATA AACCCTCTTG 60 CAGTTGCATC CGACTTGTGG TCTCGCTGTT CCTTGGGAGG GTCTCCTCTG AGTGATTGAC 120 TACCCGTCAG CGGGGGTCTT TCATTTGGGG GCTCGTCCGG GATCGGGAGA CCCCTGCCCA 180 GGGACCACCG ACCCACCACC GGGAGGTAAG CTGGCCAGCA ACTTATCTGT GTCTGTCCGA 240 TTGTCTAGTG TCTATGACTG ATTTTATGCG CCTGCGTCGG TACTAGTTAG CTAACTAGCT 300 CTGTATCTGG CGGACCCGTG GTGGAACTGA CGAGTTCGGA ACACCCGGCC GCAACCCTGG 360 GAGACGTCCC AGGGACTTCG GGGGCCGTTT TTGTGGCCCG ACCTGAGTCC AAAAATCCCG 420 ATCGTTTTGG ACTCTTTGGT GCACCCCCCT TAGAGGAGGG ATATGTGGTT CTGGTAGGAG 480 ACGAGAACCT AAAACAGTTC CCGCCTCCGT CTGAATTTTT GCTTTCGGTT TGGGACCGAA 540 GCCGCGCCGC GCGTCTTGTC TGCTGCAGCA TCGTTCTGTG TTGTCTCTGT CTGACTGTGT 600 TTCTGTATTT GTCTGAGAAT ATGGGCCAGA CTGTTACCAC TCCCTTAAGT TTGACCTTAG 660 GTCACTGGAA AGATGTCGAG CGGATCGCTC ACAACCAGTC GGTAGATGTC AAGAAGAGAC 720 GTTGGGTTAC CTTCTGCTCT GCAGAATGGC CAACCTTTAA CGTCGGATGG CCGCGAGACG 780 GCACCTTTAA CCGAGACCTC ATCACCCAGG TTAAGATCAA GGTCTTTTCA CCTGGCCCGC 840 ATGGACACCC AGACCAGGTC CCCTACATCG TGACCTGGGA AGCCTTGGCT TTTGACCCCC 900 CTCCCTGGGT CAAGCCCTTT GTACACCCTA AGCCTCCGCC TCCTCTTCCT CCATCCGCCC 960 CGTCTCTCCC CCTTGAACCT CCTCGTTCGA CCCCGCCTCG ATCCTCCCTT TATCCAGCCC 1020 TCACTCCπC TCTAGGCGCC AAACCTAAAC CTCAAGTTCT TTCTGACAGT GGGGGGCCGC 1080 TCATCGACCT ACTTACAGAA GACCCCCCGC CTTATAGGGA CCCAAGACCA CCCCCTTCCG 1140 ACAGGGACGG AAATGGTGGA GAAGCGACCC CTGCGGGAGA GGCACCGGAC CCCTCCCCAA 1200 TGGCATCTCG CCTACGTGGG AGACGGGAGC CCCCTGTGGC CGACTCCACT ACCTCGCAGG 1260 CATTCCCCCT CCGCGCAGGA GGAAACGGAC AGCTTCAATA CTGGCCGTTC TCCTCTTCTG 1320 ACCTTTACAA CTGGAAAAAT AATAACCCTT CTTTTTCTGA AGATCCAGGT AAACTGACAG 1380 CTCTGATCGA GTCTGTTCTC ATCACCCATC AGCCCACCTG GGACGACTGT CAGCAGCTGT 1440 TGGGGACTCT GCTGACCGGA GAAGAAAAAC AACGGGTGCT CTTAGAGGCT AGAAAGGCGG 1500 TGCGGGGCGA TGATGGGCGC CCCACTCAAC TGCCCAATGA AGTCGATGCC GCTTTTCCCC 1560 TCGAGCGCCC AGACTGGGAT TACACCACCC AGGCAGGTAG GAACCACCTA GTCCACTATC 1620 GCCAGTTGCT CCTAGCGGGT CTCCAAAACG CGGGCAGAAG CCCCACCAAT TTGGCCAAGG 1680 TAAAAGGAAT AACACAAGGG CCCAATGAGT CTCCCTCGGC CTTCCTAGAG AGACTTAAGG 1740 AAGCCTATCG CAGGTACACT CCTTATGACC CTGAGGACCC AGGGCAAGAA ACTAATGTGT 1800 CTATGTCTTT CATTTGGCAG TCTGCCCCAG ACATTGGGAG AAAGTTAGAG AGGTTAGAAG 1860 ATTTAAAAAA CAAGACGCTT GGAGATTTGG TTAGAGAGGC AGAAAAGATC TTTAATAAAC 1920 GAGAAACCCC GGAAGAAAGA GAGGAACGTA TCAGGAGAGA AACAGAGGAA AAAGAAGAAC 1980 GCCGTAGGAC AGAGGATGAG CAGAAAGAGA AAGAAAGAGA TCGTAGGAGA CATAGAGAGA 2040 TGAGCAAGCT ATTGGCCACT GTCGTTAGTG GACAGAAACA GGATAGACAG GGAGGAGAAC 2100 GAAGGAGGTC CCAACTCGAT CGCGACCAGT GTGCCTACTG CAAAGAAAAG GGGCACTGGG 2160 CTAAAGATTG TCCCAAGAAA CCACGAGGAC CTCGGGGACC AAGACCCCAG ACCTCCCTCC 2220 TGACCCTAGA TGACTAGGGA GGTCAGGGTC AGGAGCCCCC CCCTGAACCC AGGATAACCC 2280 TCAAAGTCGG GGGGCAACCC GTCACCTTCC TGGTAGATAC TGGGGCCCAA CACTCCGTGC 2340 TGACCCAAAA TCCTGGACCC CTAAGTGATA AGTCTGCCTG GGTCCAAGGG GCTACTGGAG 2400 GAAAGCGGTA TCGCTGGACC ACGGATCGCA AAGTACATCT AGCTACCGGT AAGGTCACCC 2460 ACTCTTTCCT CCATGTACCA GACTGTCCCT ATCCTCTGTT AGGAAGAGAT TTGCTGACTA 2520 AACTAAAAGC CCAAATCCAC TTTGAGGGAT CAGGAGCTCA GGTTATGGGA CCAATGGGGC 2580 AGCCCCTGCA AGTGTTGACC CTAAATATAG AAGATGAGCA TCGGCTACAT GAGACCTCAA 2640 AAGAGCCAGA TGTTTCTCTA GGGTCCACAT GGCTGTCTGA TTTTCCTCAG GCCTGGGCGG 2700 AAACCGGGGG CATGGGACTG GCAGTTCGCC AAGCTCCTCT GATCATACCT CTGAAAGCAA 2760 CCTCTACCCC CGTGTCCATA AAACAATACC CCATGTCACA AGAAGCCAGA CTGGGGATCA 2820 AGCCCCACAT ACAGAGACTG TTGGACCAGG GAATACTGGT ACCCTGCCAG TCCCCCTGGA 2880 ACACGCCCCT GCTACCCGTT AAGAAACCAG GGACTAATGA TTATAGGCCT GTCCAGGATC 2940 TGAGAGAAGT CAACAAGCGG GTGGAAGACA TCCACCCCAC CGTGCCCAAC CCTTACAACC 3000 TCTTGAGCGG GCTCCCACCG TCCCACCAGT GGTACACTGT GCTTGATTTA AAGGATGCCT 3060 TTTTCTGCCT GAGACTCCAC CCCACCAGTC AGCCTCTCTT CGCCTTTGAG TGGAGAGATC 3120 CAGAGATGGG AATCTCAGGA CAATTGACCT GGACCAGACT CCCACAGGGT TTCAAAAACA 3180 GTCCCACCCT GTTTGATGAG GCACTGCACA GAGACCTAGC AGACTTCCGG ATCCAGCACC 3240 CAGACTTGAT CCTGCTACAG TACGTGGATG ACTTACTGCT GGCCGCCACT TCTGAGCTAG 3300 ACTGCCAACA AGGTACTCGG GCCCTGTTAC AAACCCTAGG GAACCTCGGG TATCGGGCCT 3360 CGGCCAAGAA AGCCCAAATT TGCCAGAAAC AGGTCAAGTA TCTGGGGTAT CTTCTAAAAG 3420 AGGGTCAGAG ATGGCTGACT GAGGCCAGAA AAGAGACTGT GATGGGGCAG CCTACTCCGA 3480 AGACCCCTCG ACAACTAAGG GAGTTCCTAG GGACGGCAGG CTTCTGTCGC CTCTGGATCC 3540 CTGGGTTTGC AGAAATGGCA GCCCCCTTGT ACCCTCTCAC CAAAACGGGG ACTCTGTTTA 3600 ATTGGGGCCC AGACCAACAA AAGGCCTATC AAGAAATCAA GCAAGCTCTT CTAACTGCCC 3660 CAGCCCTGGG GTTGCCAGAT TTGACTAAGC CCTTTGAACT CTTTGTCGAC GAGAAGCAGG 3720 GCTACGCCAA AGGTGTCCTA ACGCAAAAAC TGGGACCTTG GCGTCGGCCG GTGGCCTACC 3780 TGTCCAAAAA GCTAGACCCA GTAGCAGCTG GGTGGCCCCC TTGCCTACGG ATGGTAGCAG 3840 CCATTGCCGT ACTGACAAAG GATGCAGGCA AGCTAACCAT GGGACAGCCA CTAGTCATTC 3900 TGGCCCCCCA TGCAGTAGAG GCACTAGTCA AACAACCCCC CGACCGCTGG CTTTCCAACG 3960 CCCGGATGAC TCACTATCAG GCCTTGCTTT TGGACACGGA CCGGGTCCAG TTCGGACCGG 4020 TGGTAGCCCT GAACCCGGCT ACGCTGCTCC CACTGCCTGA GGAAGGGCTG CAACACAACT 4080 GCCTTGATAT CCTGGCCGAA GCCCACGGAA CCCGACCCGA CCTAACGGAC CAGCCGCTCC 4140 CAGACGCCGA CCACACCTGG TACACGGATG GAAGCAGTCT CTTACAAGAG GGACAGCGTA 4200 AGGCGGGAGC TGCGGTGACC ACCGAGACCG AGGTAATCTG GGCTAAAGCC CTGCCAGCCG 4260 GGACATCCGC TCAGCGGGCT GAACTGATAG CACTCACCCA GGCCCTAAAG ATGGCAGAAG 4320 GTAAGAAGCT AAATGTTTAT ACTGATAGCC GTTATGCTTT TGCTACTGCC CATATCCATG 4380 GAGAAATATA CAGAAGGCGT GGGTTGCTCA CATCAGAAGG CAAAGAGATC AAAAATAAAG 4440 ACGAGATCTT GGCCCTACTA AAAGCCCTCT TTCTGCCCAA AAGACTTAGC ATAATCCATT 4500 GTCCAGGACA TCAAAAGGGA CACAGCGCCG AGGCTAGAGG CAACCGGATG GCTGACCAAG 4560 CGGCCCGAAA GGCAGCCATC ACAGAGACTC CAGACACCTC TACCCTCCTC ATAGAAAATT 4620 CATCACCCTA CACCTCAGAA CATTTTCATT ACACAGTGAC TGATATAAAG GACCTAACCA 4680 AGTTGGGGGC CATTTATGAT AAAACAAAGA AGTATTGGGT CTACCAAGGA AAACCTGTGA 4740 TGCCTGACCA GTTTACTTTT GAATTATTAG ACTTTCTTCA TCAGCTGACT CACCTCAGCT 4800 TCTCAAAAAT GAAGGCTCTC CTAGAGAGAA GCCACAGTCC CTACTACATG CTGAACCGGG 4860 ATCGAACACT CAAAAATATC ACTGAGACCT GCAAAGCTTG TGCACAAGTC AACGCCAGCA 4920 AGTCTGCCGT TAAACAGGGA ACTAGGGTCC GCGGGCATCG GCCCGGCACT CATTGGGAGA 4980 TCGATTTCAC CGAGATAAAG CCCGGATTGT ATGGCTATAA ATATCTTCTA GTTTTTATAG 5040 ATACCTTTTC TGGCTGGATA GAAGCCTTCC CAACCAAGAA AGAAACCGCC AAGGTCGTAA 5100 CCAAGAAGCT ACTAGAGGAG ATCTTCCCCA GGTTCGGCAT GCCTCAGGTA TTGGGAACTG 5160 ACAATGGGCC TGCCTTCGTC TCCAAGGTGA GTCAGACAGT GGCCGATCTG TTGGGGATTG 5220 ATTGGAAATT ACATTGTGCA TACAGACCCC AAAGCTCAGG CCAGGTAGAA AGAATGAATA 5280 GAACCATCAA GGAGACTTTA ACTAAATTAA CGCTTGCAAC TGGCTCTAGA GACTGGGTGC 5340 TCCTACTCCC CTTAGCCCTG TACCGAGCCC GCAACACGCC GGGCCCCCAT GGCCTCACCC 5400 CATATGAGAT CTTATATGGG GCACCCCCGC CCCTTGTAAA CTTCCCTGAC CCTGACATGA 5460 CAAGAGTTAC TAACAGCCCC TCTCTCCAAG CTCACTTACA GGCTCTCTAC TTAGTCCAGC 5520 ACGAAGTCTG GAGACCTCTG GCGGCAGCCT ACCAAGAACA ACTGGACCGA CCGGTGGTAC 5580 CTCACCCTTA CCGAGTCGGC GACACAGTGT GGGTCCGCCG ACACCAGACT AAGAACCTAG 5640 AACCTCGCTG GAAAGGACCT TACACAGTCC TGCTGACCAC CCCCACCGCC CTCAAAGTAG 5700 ACGGCATCGC AGCTTGGATA CACGCCGCCC ACGTGAAGGC TGCCGACCCC GGGGGTGGAC 5760 CATCCTCTAG ACTGACATGG CGCGTTCAAC GCTCTCAAAA CCCCTTAAAA ATAAGGTTAA 5820 CCCGCGAGGC CCCCTAATCC CCTTAATTCT TCTGATGCTC AGAGGGGTCA GTACTGCTTC 5880 GCCCGGCTCC AGTCCTCATC AAGTCTATAA TATCACCTGG GAGGTAACCA ATGGAGATCG 5940 GGAGACGGTA TGGGCAACTT CTGGCAACCA CCCTCTGTGG ACCTGGTGGC CTGACCTTAC 6000 CCCAGATTTA TGTATGTTAG CCCACCATGG ACCATCTTAT TGGGGGCTAG AATATCAATC 6060 CCCTTTTTCT TCTCCCCCGG GGCCCCCTTG TTGCTCAGGG GGCAGCAGCC CAGGCTGTTC 6120 CAGAGACTGC GAAGAACCTT TAACCTCCCT CACCCCTCGG TGCAACACTG CCTGGAACAG 6180 ACTCAAGCTA GACCAGACAA CTCATAAATC AAATGAGGGA TTTTATGTTT GCCCCGGGCC 6240 CCACCGCCCC CGAGAATCCA AGTCATGTGG GGGTCCAGAC TCCTTCTACT GTGCCTATTG 6300 GGGCTGTGAG ACAACCGGTA GAGCTTACTG GAAGCCCTCC TCATCATGGG ATTTCATCAC 6360 AGTAAACAAC AATCTCACCT CTGACCAGGC TGTCCAGGTA TGCAAAGATA ATAAGTGGTG 6420 CAACCCCTTA GTTATTCGGT TTACAGACGC CGGGAGACGG GTTACTTCCT GGACCACAGG 6480 ACATTACTGG GGCTTACGTT TGTATGTCTC CGGACAAGAT CCAGGGCTTA CATTTGGGAT 6540 CCGACTCAGA TACCAAAATC TAGGACCCCG CGTCCCAATA GGGCCAAACC CCGTTCTGGC 6600 AGACCAACAG CCACTCTCCA AGCCCAAACC TGTTAAGTCG CCTTCAGTCA CCAAACCACC 6660 CAGTGGGACT CCTCTCTCCC CTACCCAACT TCCACCGGCG GGAACGGAAA ATAGGCTGCT 6720 AAACTTAGTA GACGGAGCCT ACCAAGCCCT CAACCTCACC AGTCCTGACA AAACCCAAGA 6780 GTGCTGGTTG TGTCTAGTAG CGGGACCCCC CTACTACGAA GGGGTTGCCG TCCTGGGTAC 6840 CTACTCCAAC CATACCTCTG CTCCAGCCAA CTGCTCCGTG GCCTCCCAAC ACAAGTTGAC 6900 CCTGTCCGAA GTGACCGGAC AGGGACTCTG CATAGGAGCA GTTCCCAAAA CACATCAGGC 6960 CCTATGTAAT ACCACCCAGA CAAGCAGTCG AGGGTCCTAT TATCTAGTTG CCCCTACAGG 7020 TACCATGTGG GCTTGTAGTA CCGGGCTTAC TCCATGCATC TCCACCACCA TACTGAACCT 7080 TACCACTGAT TATTGTGTTC TTGTCGAACT CTGGCCAAGA GTCACCTATC ATTCCCCCAG 7140 CTATGTTTAC GGCCTGTTTG AGAGATCCAA CCGACACAAA AGAGAACCGG TGTCGTTAAC 7200 CCTGGCCCTA TTATTGGGTG GACTAACCAT GGGGGGAATT GCCGCTGGAA TAGGAACAGG 7260 GACTACTGCT CTAATGGCCA CTCAGCAATT CCAGCAGCTC CAAGCCGCAG TACAGGATGA 7320 TCTCAGGGAG GTTGAAAAAT CAATCTCTAA CCTAGAAAAG TCTCTCACTT CCCTGTCTGA 7380 AGTTGTCCTA CAGAATCGAA GGGGCCTAGA CTTGTTATTT CTAAAAGAAG GAGGGCTGTG 7440 TGCTGCTCTA AAAGAAGAAT GTTGCTTCTA TGCGGACCAC ACAGGACTAG TGAGAGACAG 7500 CATGGCCAAA TTGAGAGAGA GGCTTAATCA GAGACAGAAA CTGTTTGAGT CAACTCAAGG 7560 ATGGTTTGAG GGACTGTTTA ACAGATCCCC TTGGTTTACC ACCTTGATAT CTACCATTAT 7620 GGGACCCCTC ATTGTACTCC TAATGATTTT GCTCTTCGGA CCCTGCATTC TTAATCGATT 7680 AGTCCAATTT GTTAAAGACA GGATATCAGT GGTCCAGGCT CTAGTTTTGA CTCAACAATA 7740 TCACCAGCTG AAGCCTATAG AGTACGAGCC ATAGATAAAA TAAAAGATTT TATTTAGTCT 7800 CCAGAAAAAG GGGGGAATGA AAGACCCCAC CTGTAGGTTT GGCAAGCTAG CTTAAGTAAC 7860 GCCATTTTGC AAGGCATGGA AAAATACATA ACTGAGAATA GAGAAGTTCA GATCAAGGTC 7920 AGGAACAGAT GGAACAGCTG AATATGGGCC AAACAGGATA TCTGTGGTAA GCAGTTCCTG 7980 CCCCGGCTCA GGGCCAAGAA CAGATGGAAC AGCTGAATAT GGGCCAAACA GGATATCTGT 8040 GGTAAGCAGT TCCTGCCCCG GCTCAGGGCC AAGAACAGAT GGTCCCCAGA TGCGGTCCAG 8100 CCCTCAGCAG TTTCTAGAGA ACCATCAGAT GTTTCCAGGG TGCCCCAAGG ACCTGAAATG 8160 ACCCTGTGCC TTATTTGAAC TAACCAATCA GTTCGCTTCT CGCTTCTGTT CGCGCGCTTC 8220 TGCTCCCCGA GCTCAATAAA AGAGCCCACA ACCCCTCACT CGGGGCGCCA GTCCTCCGAT 8280 TGACTGAGTC GCCCGGGTAC CCGTGTATCC AATAAACCCT CTTGCAGTTG CA 8332 (2) INFORMATION FOR SEQ ID N0:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: GGTAACAGTC TGGCCCGAAT TCTCAGACAA ATACAG 36 2) INFORMATION FOR SEQ ID NO:3: (l) SEQUENCE CHARACTERISTICS: (A) LENGTH: 38 base pairs (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: CTGTATTTGT CTGAGAATTA AGGCTAGACT GTTACCAC 38 (2) INFORMATION FOR SEQ ID N0:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 22 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:4: ATATATATAT ATCGATACCA TG 22 (2) INFORMATION FOR SEQ ID N0:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 16 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:5: GGCGCCAAAC CTAAAC 16 (2) INFORMATION FOR SEQ ID N0:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 5 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:6: Ser Lys Asn Tyr Pro (2) INFORMATION FOR SEQ ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: ACCATCCTCT GGACGGACAT G 21 (2) INFORMATION FOR SEQ ID NO:8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:8: ACCCGGCCGT GGACGGACAT G 21 (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 449 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 20..439 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: ATATATATAT ATCGATACC ATG GGG CAA ACC GTG ACT ACC CCT CTG TCC CTC 52 Met Gly Gin Thr Val Thr Thr Pro Leu Ser Leu 1 5 10 ACA CTG GGC CAT TGG AAG GAC GTG GAA AGA ATT GCC CAT AAT CAA AGC 100 Thr Leu Gly His Trp Lys Asp Val Glu Arg He Ala His Asn Gin Ser 15 20 25 GTG GAC TGC AAA AAA CGC AGG TGG GTG ACA TTT TGT AGC GCC GAG TGG 148 Val Asp Cys Lys Lys Arg Arg Trp Val Thr Phe Cys Ser Ala Glu Trp 30 35 40 CCC ACA TTC AAT GTT GGC TGG CCT AGG GAT GGA ACT TTC AAT CGC GAT 196 Pro Thr Phe Asn Val Gly Trp Pro Arg Asp Gly Thr Phe Asn Arg Asp 45 50 55 CTG ATT ACT CAA GTG AAA ATT AAA GTG TTC AGC CCC GGA CCC CAC GGC 244 Leu He Thr Gin Val Lys He Lys Val Phe Ser Pro Gly Pro His Gly 60 65 70 75 CAT CCC GAT CAA GTT CCT TAT ATT GTC ACA TGG GAG GCT CTC GCT TTC 292 His Pro Asp Gin Val Pro Tyr He Val Thr Trp Glu Ala Leu Ala Phe 80 85 90 GAT CCA CCA CCT TGG GTG AAA CCA TTC GTG CAT CCC AAA CCA CCT CCA 340 Asp Pro Pro Pro Trp Val Lys Pro Phe Val His Pro Lys Pro Pro Pro 95 100 105 CCC CTC CCA CCC AGC GCT CCT AGC CTG CCC TTG GAG CCC CCA CGA AGC 388 Pro Leu Pro Pro Ser Ala Pro Ser Leu Pro Leu Glu Pro Pro Arg Ser 110 115 120 ACA CCA CCC AGG AGC AGC TTG TAC CCT GCT CTG ACC CCC AGC CTC GGC 436 Thr Pro Pro Arg Ser Ser Leu Tyr Pro Ala Leu Thr Pro Ser Leu Gly 125 130 135 GCC AAACCTAAAC 449 Al 140 (2) INFORMATION FOR SEQ ID NO:10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 140 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: Met Gly Gin Thr Val Thr Thr Pro Leu Ser Leu Thr Leu Gly His Trp 1 5 10 15 Lys Asp Val Glu Arg He Ala His Asn Gin Ser Val Asp Cys Lys Lys 20 25 30 Arg Arg Trp Val Thr Phe Cys Ser Ala Glu Trp Pro Thr Phe Asn Val 35 40 45 Gly Trp Pro Arg Asp Gly Thr Phe Asn Arg Asp Leu He Thr Gin Val 50 55 60 Lys He Lys Val Phe Ser Pro Gly Pro His Gly His Pro Asp Gin Val 65 70 75 80 Pro Tyr He Val Thr Trp Glu Ala Leu Ala Phe Asp Pro Pro Pro Trp 85 90 95 Val Lys Pro Phe Val His Pro Lys Pro Pro Pro Pro Leu Pro Pro Ser 100 105 110 Ala Pro Ser Leu Pro Leu Glu Pro Pro Arg Ser Thr Pro Pro Arg Ser 115 120 125 Ser Leu Tyr Pro Ala Leu Thr Pro Ser Leu Gly Ala 130 135 140 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 420 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..420 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11: ATG GGC CAG ACT GTT ACC ACT CCC TTA AGT TTG ACC TTA GGT CAC TGG 48 Met Gly Gin Thr Val Thr Thr Pro Leu Ser Leu Thr Leu Gly His Trp 1 5 10 15 AAA GAT GTC GAG CGG ATC GCT CAC AAC CAG TCG GTA GAT GTC AAG AAG 96 Lys Asp Val Glu Arg He Ala His Asn Gin Ser Val Asp Val Lys Lys 20 25 30 AGA CGT TGG GTT ACC TTC TGC TCT GCA GAA TGG CCA ACC TTT AAC GTC 144 Arg Arg Trp Val Thr Phe Cys Ser Ala Glu Trp Pro Thr Phe Asn Val 35 40 45 GGA TGG CCG CGA GAC GGC ACC TTT AAC CGA GAC CTC ATC ACC CAG GTT 192 Gly Trp Pro Arg Asp Gly Thr Phe Asn Arg Asp Leu He Thr Gin Val 50 55 60 AAG ATC AAG GTC TTT TCA CCT GGC CCG CAT GGA CAC CCA GAC CAG GTC 240 Lys He Lys Val Phe Ser Pro Gly Pro His Gly His Pro Asp Gin Val 65 70 75 80 CCC TAC ATC GTG ACC TGG GAA GCC TTG GCT TTT GAC CCC CCT CCC TGG 288 Pro Tyr He Val Thr Trp Glu Ala Leu Ala Phe Asp Pro Pro Pro Trp 85 90 95 GTC AAG CCC TTT GTA CAC CCT AAG CCT CCG CCT CCT CTT CCT CCA TCC 336 Val Lys Pro Phe Val His Pro Lys Pro Pro Pro Pro Leu Pro Pro Ser 100 105 110 GCC CCG TCT CTC CCC CTT GAA CCT CCT CGT TCG ACC CCG CCT CGA TCC 384 Ala Pro Ser Leu Pro Leu Glu Pro Pro Arg Ser Thr Pro Pro Arg Ser 115 120 125 TCC CTT TAT CCA GCC CTC ACT CCT TCT CTA GGC GCC 420 Ser Leu Tyr Pro Ala Leu Thr Pro Ser Leu Gly Ala 130 135 140 (2) INFORMATION FOR SEQ ID NO:12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 140 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: Met Gly Gin Thr Val Thr Thr Pro Leu Ser Leu Thr Leu Gly His Trp 1 5 10 15 Lys Asp Val Glu Arg He Ala His Asn Gin Ser Val Asp Val Lys Lys 20 25 30 Arg Arg Trp Val Thr Phe Cys Ser Ala Glu Trp Pro Thr Phe Asn Val 35 40 45 Gly Trp Pro Arg Asp Gly Thr Phe Asn Arg Asp Leu He Thr Gin Val 50 55 60 Lys He Lys Val Phe Ser Pro Gly Pro His Gly His Pro Asp Gin Val 65 70 75 80 Pro Tyr He Val Thr Trp Glu Ala Leu Ala Phe Asp Pro Pro Pro Trp 85 90 95 Val Lys Pro Phe Val His Pro Lys Pro Pro Pro Pro Leu Pro Pro Ser 100 105 110 Ala Pro Ser Leu Pro Leu Glu Pro Pro Arg Ser Thr Pro Pro Arg Ser 115 120 125 Ser Leu Tyr Pro Ala Leu Thr Pro Ser Leu Gly Ala 130 135 140 (2) INFORMATION FOR SEQ ID NO:13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2001 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13: GGCCGACACC CAGAGTGGAC CATCCTCTGG ACGGACATGG CGCGTTCAAC GCTCTCAAAA 60 CCCCCTCAAG ATAAGATTAA CCCGTGGAAG CCCTTAATAG TCATGGGAGT CCTGTTAGGA 120 GTAGGGATGG CAGAGAGCCC CCATCAGGTC TTTAATGTAA CCTGGAGAGT CACCAACCTG 180 ATGACTGGGC GTACCGCCAA TGCCACCTCC CTCCTGGGAA CTGTACAAGA TGCCTTCCCA 240 AAATTATATT TTGATCTATG TGATCTGGTC GGAGAGGAGT GGGACCCTTC AGACCAGGAA 300 CCGTATGTCG GGTATGGCTG CAAGTACCCC GCAGGGAGAC AGCGGACCCG GACTTTTGAC 360 TTTTACGTGT GCCCTGGGCA TACCGTAAAG TCGGGGTGTG GGGGACCAGG AGAGGGCTAC 420 TGTGGTAAAT GGGGGTGTGA AACCACCGGA CAGGCTTACT GGAAGCCCAC ATCATCGTGG 480 GACCTAATCT CCCTTAAGCG CGGTAACACC CCCTGGGACA CGGGATGCTC TAAAGTTGCC 540 TGTGGCCCCT GCTACGACCT CTCCAAAGTA TCCAATTCCT TCCAAGGGGC TACTCGAGGG 600 GGCAGATGCA ACCCTCTAGT CCTAGAATTC ACTGATGCAG GAAAAAAGGC TAACTGGGAC 660 GGGCCCAAAT CGTGGGGACT GAGACTGTAC CGGACAGGAA CAGATCCTAT TACCATGTTC 720 TCCCTGACCC GGCAGGTCCT TAATGTGGGA CCCCGAGTCC CCATAGGGCC CAACCCAGTA 780 TTACCCGACC AAAGACTCCC TTCCTCACCA ATAGAGATTG TACCGGCTCC ACAGCCACCT 840 AGCCCCCTCA ATACCAGTTA CCCCCCTTCC ACTACCAGTA CACCCTCAAC CTCCCCTACA 900 AGTCCAAGTG TCCCACAGCC ACCCCCAGGA ACTGGAGATA GACTACTAGC TCTAGTCAAA 960 GGAGCCTATC AGGCGCTTAA CCTCACCAAT CCCGACAAGA CCCAAGAATG TTGGCTGTGC 1020 TTAGTGTCGG GACCTCCTTA TTACGAAGGA GTAGCGGTCG TGGGCACTTA TACCAATCAT 1080 TCCACCGCTC CGGCCAACTG TACGGCCACT TCCCAACATA AGCTTACCCT ATCTGAAGTG 1140 ACAGGACAGG GCCTATGCAT GGGGGCAGTA CCTAAAACTC ACCAGGCCTT ATGTAACACC 1200 ACCCAAAGCG CCGGCTCAGG ATCCTACTAC CTTGCAGCAC CCGCCGGAAC AATGTGGGCT 1260 TGCAGCACTG GATTGACTCC CTGCTTGTCC ACCACGGTGC TCAATCTAAC CACAGATTAT 1320 TGTGTATTAG TTGAACTCTG GCCCAGAGTA ATTTACCACT CCCCCGATTA TATGTATGGT 1380 CAGCTTGAAC AGCGTACCAA ATATAAAAGA GAGCCAGTAT CATTGACCCT GGCCCTTCTA 1440 CTAGGAGGAT TAACCATGGG AGGGATTGCA GCTGGAATAG GGACGGGGAC CACTGCCTTA 1500 ATTAAAACCC AGCAGTTTGA GCAGCTTCAT GCCGCTATCC AGACAGACCT CAACGAAGTC 1560 GAAAAGTCAA TTACCAACCT AGAAAAGTCA CTGACCTCGT TGTCTGAAGT AGTCCTACAG 1620 AACCGCAGAG GCCTAGATTT GCTATTCCTA AAGGAGGGAG GTCTCTGCGC AGCCCTAAAA 1680 GAAGAATGTT GTTTTTATGC AGACCACACG GGGCTAGTGA GAGACAGCAT GGCCAAATTA 1740 AGAGAAAGGC TTAATCAGAG ACAAAAACTA TTTGAGACAG GCCAAGGATG GTTCGAAGGG 1800 CTGTTTAATA GATCCCCCTG GTTTACCACC TTAATCTCCA CCATCATGGG ACCTCTAATA 1860 GTACTCTTAC TGATCTTACT CTTTGGACCT TGCATTCTCA ATCGATTGGT CCAATTTGTT 1920 AAAGACAGGA TCTCAGTGGT CCAGGCTCTG GTTTTGACTC AGCAATATCA CCAGCTAAAA 1980 CCCATAGAGT ACGAGCCATG A 2001 (2) INFORMATION FOR SEQ ID NO:14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 12 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14: CTAGCTAGCT AG 12 (2) INFORMATION FOR SEQ ID NO:15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 64 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15: ATATATATAT ATCGATACCA TGGGGCAAAC CGTGACTACC CCTCTGTCCC TCACACTGGC 60 CCAA 64 (2) INFORMATION FOR SEQ ID NO:16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 51 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16: TTGATTATGG GCATTTCTTT CCACGTCCTT CCAATGGCCC AGTGTGAGGG A 51 (2) INFORMATION FOR SEQ ID NO:17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 72 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17: AGAATTGCCC ATAATCAAAG CGTGGACGTC AAAAAACGCA GGTGGGTGAC ATTTTGTAGC 60 GCCGAGTGGC CC 72 (2) INFORMATION FOR SEQ ID NO:18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 52 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:18: AAGTTCCATC CCTAGGCCAG CCAACATTGA ATGTGGGCCA CTCGGCGCTA CA 52 (2) INFORMATION FOR SEQ ID NO:19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 71 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19: GGCCTAGGGA GGAACTTTCA ATCGCGATCT GATTACTCAA GTGAAAATTA AAGTGTTCAG 60 CCCCGGACCC C 71 (2) INFORMATION FOR SEQ ID N0:20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 52 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20: GTGACAATAT AAGGAACTTG ATCGGGATGG CCGTGGGGTC CGGGGCTGAA CA 52 (2) INFORMATION FOR SEQ ID N0:21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 72 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:21: AGTTCCTTAT AπGTCACAT CGGAGGCTCT CGCTTTCGAT CCACCACCTT GGGTGAAACC 60 ATTCGTGCAT CC 72 (2) INFORMATION FOR SEQ ID NO:22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 52 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22 AGGAGCGCTG GGTGGGAGGG GTGGAGGTGG TTTGGGATGC ACGAATGGTT TC 52 (2) INFORMATION FOR SEQ ID N0:23 (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 72 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:23: CTCCCACCCA GCGCTCCTAG CCTGCCCTTG GAGCCCCCAC GAAGCACACC ACCCAGGAGC 60 AGCTTGTACC CT 72 (2) INFORMATION FOR SEQ ID N0:24: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 52 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:24: GTTTAGGTπ GGCGCCGAGG CTGGGGGTCA GAGCAGGGTA CAAGCTGCTC CT 52 (2) INFORMATION FOR SEQ ID NO:25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 19 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: ATATATATAT ATCGATACC 19 (2) INFORMATION FOR SEQ ID NO:26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:26: GTTTAGGTTT GGCGCCGAGG 20

Claims: Claims We claim 1 A method for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising (a) administering to a warm-blooded animal a targeting element coupled to a first molecule of a high affinity binding pair, said coupled targeting element being capable of specifically binding to a selected cell type in said warm¬ blooded animal; and (b) administering to said animal a gene delivery vehicle coupled to a second molecule of said high affinity binding pair, said second molecule being capable of specifically binding to said first molecule such that said gene delivery vehicle is targeted to said selected cell type 2 The method according to claim 1 further comprising, subsequent to the step of administering a coupled targeting element and prior to the step of administering a coupled gene delivery vehicle, administering to said animal a clearing agent 3 A method for targeting a gene delivery vehicle to a selected cell type in a warm-blooded animal, comprising (a) administering to a warm-blooded animal a gene delivery vehicle coupled to a first molecule of a high affinity binding pair; and (b) administering to said warm-blooded animal a targeting element coupled to a second molecule, said coupled targeting element being capable of specifically binding to a selected cell type in said warm-blooded animal, and said second molecule being capable of specifically binding to said first molecule such that said gene delivery vehicle is targeted to said selected cell type 4 The method according to any one of claims 1 to 3 wherein said targeting element is selected from the group consisting of antibody and antibody fragments 5 The method according to any one of claims 1 to 3 wherein said targeting element is selected from the group consisting of bombesin, gastrin-release peptide, cell adhesion peptides, substance P, neuromedin-B, neuromedin-C and metenkephalin 6 The method according to any one of claims 1 to 3 wherein said targeting element is selected from the group consisting of EGF, alpha- and beta-TGF, neurotensin, melanocyte stimulating hormone, follicle stimulating hormone, lutenizing hormone and human growth hormone 7 The method according to any one of claims 1 to 3 wherein said targeting element is a ligand for a cell surface receptor selected from the group consisting of low density lipoproteins, transferrin and insulin 8 The method according to any one of claims 1 to 3 wherein said targeting element is a fibrinolytic enzyme 9. The method according to any one of claims 1 to 3 wherein said targeting element is a immune accessory molecule selected from the group consisting of IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, 1L-8, IL-9, IL-10, IL-1 1, IL-12, IL-13, α interferon, β interferon, γ interferon, GM-CSF, G-CSF, M-CSF and erythropoietin. 10. The method according to any one of claims 1 to 3 wherein said high affinity binding pair is selected from the group consisting of biotin/avidin, cytostatin papain, val-phosphonate/carboxypeptidase A and 4CABP/RuBisCo 1 1 The method according to any one of claims 1 to 3 wherein said high affinity binding pair is an antigen/antibody binding pair 12 The method according to any one of claims 1 to 3 wherein said gene delivery vehicle is a retroviral vector construct 13 The method according to claim 12 wherein said retroviral vector construct is constmcted from a virus selected from the group consisting of Avian Leukosis Virus, Bovine Leukemia Virus, Murine Leukemia Virus, Mink-Cell Focus-Inducing Virus, Murine Sarcoma Virus, Reticuloendotheliosis Virus, Gibbon Ape Leukemia Virus, Mason Pfizer Leukemia Virus and Rous Sarcoma Virus 14 The method according to claim 12 wherein said Murine Leukemia Virus is selected from the group consisting of Abelson, Friend, Graffi, Gross, Kirsten, Harvey Sarcoma Virus, Moloney Murine Leukemia Virus and Rauscher 15 The method according to any one of claims 1 to 3 wherein said gene delivery vehicle is selected from the group consisting of poliovirus vectors, rhinovirus vectors, pox virus vectors, canary pox virus vectors, vaccinia virus vectors, influenza virus vectors, adenovirus vectors, parvovirus vectors, adeno-associated viral vectors, herpesvirus vectors, SV 40 vectors, HIV vectors, measles virus vectors, astrovirus vectors, corona virus vectors and Sindbis viral vectors 16 The method according to any one of claims 1 to 3 wherein said gene delivery vehicle is selected from the group consisting of polycation condensed nucleic acids, naked DNA and producer cell lines 17 The method according to any one of claims 1 to 3 wherein said gene delivery vehicle contains a heterologous sequence 18 The method according to claim 17 wherein said heterologous sequence is a gene encoding a cytotoxic protein 19 The method according to claim 18 wherein said cytotoxic protein is selected from the group consisting of ricin, abrin, diphtheria toxin, cholera toxin, gelonin, pokeweed, antiviral protein, tritin, Shigella toxin and Pseudomonas exotoxin A 20 The method according to claim 17 wherein said heterologous sequence is an antisense sequence 21 The method according to claim 17 wherein said heterologous sequence encodes an immune accessory molecule 22 The method according to claim 21 wherein said immune accessory molecule is selected from the group consisting of α interferon, β interferon, IL-1, IL-3, IL-4, IL-5, IL-6, 1L-7, IL-8, 1L-9, IL-10, IL-1 1 and IL-13. 23 The method according to claim 21 wherein said immune accessory molecule is selected from the group consisting of IL-2, IL- 12, IL-15 and gamma-interferon 24 The method according to claim 21 wherein said immune accessory molecule is selected from the group consisting of ICAM-1 , ICAM-2, β- microglobin, LFA3, and HLA class 1 and HLA class II molecules 25 The method according to claim 17 wherein said heterologous sequence encodes a gene product that activates a compound with little or no cytotoxicity into a toxic product 26 The method according to claim 25 wherein said gene product is selected from the group consisting of HSVTK and VZVTK 27 The method according to claim 17 wherein said heterologous sequence is a ribozyme 28 The method according to claim 17 wherein said heterologous sequence is a replacement gene 29 The method according to claim 28 wherein said replacement gene encodes a protein selected from the group consisting of Factor VIII, ADA, HPRT, CFTCR and the LDL Receptor 30 The method according to claim 17 wherein said heterologous sequence encodes an immunogenic portion of a virus selected from the group consisting of HBV, HCV, HPV, EBV, FeLV, FIV and HIV 3 1 A composition, comprising a gene delivery vehicle coupled to a high affinity molecule of a high affinity binding pair, wherein said gene delivery vehicle is covalently coupled to said high affinity molecule 32 A composition, comprising a gene delivery vehicle coupled to a high affinity molecule of a high affinity binding pair, wherein said gene delivery vehicle contains or expresses said high affinity molecule 33 A composition, comprising a gene delivery vehicle coupled to a high affinity binding pair, which is coupled to a targeting element 34 The composition according to claim 33 wherein said targeting element is selected from the group consisting of antibody and antibody fragments 35 The composition according to claim 33 wherein said targeting element is selected from the group consisting of bombesin, gastrin-release peptide, cell adhesion peptides, substance P, neuromedin-B, neuromedin-C and metenkephalin 36 The composition according to claim 33 wherein said targeting element is selected from the group consisting of EGF, alpha- and beta-TGF, neurotensin, melanocyte stimulating hormone, follicle stimulating hormone, lutenizing hormone and human growth hormone 37 The composition according to claim 33 wherein said targeting element is a ligand for a cell surface receptor selected from the group consisting of low density lipoproteins, transferrin and insulin 38 The composition according to claim 33 wherein said targeting element is a fibrinolytic enzyme 39 The composition according to claim 33 wherein said targeting element is an immune accessory molecule selected from the group consisting of IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, 1L-8, IL-9, IL- 10, IL- 1 1, 1L-12, IL-13, α interferon, β interferon, γ interferon, GM-CSF, G-CSF, M-CSF and erythropoietin 40 The composition according to any one of claims 31 to 33 wherein said high affinity binding pair is selected from the group consisting of biotin/ avidin, cytostatin/papain, val-phosphonate/carboxypeptidase A and 4CABP/RuBisCo 41 The composition according to any one of claims 31 to 33 wherein said high affinity binding pair is an antigen/antibody binding pair 42 The composition according to any one of claims 3 1 to 33 wherein said gene delivery vehicle is a retroviral vector construct 43 The composition according to claim 42 wherein said retroviral vector construct is constructed from a virus selected from the group consisting of Avian Leukosis Virus, Bovine Leukemia Virus, Murine Leukemia Virus, Mink-Cell Focus-Inducing Virus, Murine Sarcoma Virus, Reticuloendotheliosis Virus, Gibbon Ape Leukemia Virus, Mason Pfizer Leukemia Virus and Rous Sarcoma Virus 44 The composition according to claim 42 wherein said Murine Leukemia Virus is selected from the group consisting of Abelson, Friend, Graffi, Gross, Kirsten, Harvey Sarcoma Virus, Moloney Murine Leukemia Virus and Rauscher 45 The composition according to any one of claims 30 or 31 wherein said gene delivery vehicle is selected from the group consisting of poliovirus vectors, rhinovirus vectors, pox virus vectors, canary pox virus vectors, vaccinia virus vectors, influenza virus vectors, adenoviais vectors, parvovirus vectors, adeno- associated viral vectors, herpesvirus vectors, SV 40 vectors, HIV vectors, measles virus vectors, corona virus vectors, astroviais vectors and Sindbis viral vectors. 46 The composition according to any one of claims 31 to 33 wherein said gene delivery vehicle is selected from the group consisting of polycation condensed nucleic acids, naked DNA and producer cells 47 The composition according to any one of claims 31 to 33 wherein said gene delivery vehicle includes a heterologous sequence 48 The composition according to claim 45 wherein said heterologous sequence is a gene encoding a cytotoxic protein 49. The composition according to claim 48 wherein said cytotoxic protein is selected from the group consisting of ricin, abrin, diphtheria toxin, cholera toxin, gelonin, pokeweed, antiviral protein, tritm, Shigella toxin and Pseudomonas exotoxin A 50 The composition according to claim 47 wherein said heterologous sequence is an antisense sequence 51 The composition according to claim 47 wherein said heterologous sequence encodes an immune accessory molecule 52 The composition according to claim 51 wherein said immune accessory molecule is selected from the group consisting of α interferon, β interferon, IL-1, IL-3, IL-4, IL-5, IL-6, 1L-7, IL-8, 1L-9, IL- 10, IL-1 1 and IL- 13 53 The composition according to claim 51 wherein said immune accessory molecule is selected from the group consisting of IL-2, IL- 12, IL-15 and gamma-interferon 54 The composition according to claim 51 wherein said immune accessory molecule is selected from the group consisting of ICAM- 1, ICAM-2, b- microglobin, LFA3, and HLA class I and HLA class II molecules 55. The composition according to claim 47 wherein said heterologous sequence encodes a gene product that activates a compound with little or no cytotoxicity into a toxic product 56 The composition according to claim 55 wherein said gene product is selected from the group consisting of HSVTK and VZVTK 57. The composition according to claim 47 wherein said heterologous sequence is a ribozyme 58 The composition according to claim 47 wherein said heterologous sequence is a replacement gene. 59 The composition according to claim 58 wherein said replacement gene encodes a protein selected from the group consisting of Factor VIII, ADA, HPRT, CFTCR and the LDL Receptor 60 The composition according to claim 47 wherein said heterologous sequence encodes an immunogenic poπion of a virus selected from the group consisting of HBV, HCV, HPV, EBV, FeLV, FIV and HIV

Inventors: BARBER JACK R, JOLLY DOUGLAS J, MOORE MARGARET DOW, RESPESS JAMES G, BARBER, JACK, R., JOLLY, DOUGLAS, J., MOORE, MARGARET, DOW, RESPESS, JAMES, G.
Applicants: VIAGENE INC, VIAGENE, INCORPORATED
Application year: 1995
Main classification: C12N15
IPC codes: A61K31, A61K35, A61K38, A61K39, A61K48, A61P3, A61P25, A61P29, A61P35, A61P43, C07H21, C12N15