METHODS OF TREATING CENTRAL NERVOUS SYSTEM ISCHEMIC OR HEMORRHAGIC INJURY USING ANTI ALPHA4 INTEGRIN ANTAGONISTS

Abstract: Methods of, and compositions for, treating central nervous system injury with an antagonist of an alpha4 subunit containing integrin are described.

Description: METHODS OF TREATING CENTRAL NERVOUS SYSTEM ISCHEMIC OR HEMORRHAGIC INJURY USING ANTI ALPHA4 INTEGRIN ANTAGONISTS Field of the Invention The present invention relates generally to methods of treatment for acute 5 Central Nervous System (CNS) ιnjur\ In particular, the invention relates to the use of antagonists of α4 integπns to treat CNS damage resulting from traumatic brain injury, spinal cord injury or stroke, including ischemic and hemorrhagic injuries The α4 integπn antagonist chosen can be used as the sole therapeutic agent or in combination with other pharmacological agents. 10 Background of the Invention Acute central nervous system ("CNS") injuries encompass a wide variety of medical and traumatic insults to the brain and spinal cord. For example, stroke is the third leading cause of death m the developed world with one stroke occurring approximately every minute in the United States. Mortality rate is about 30% but more 15 than 4 million stroke survivors are alive today, the majoπty of these individuals are left with varying degrees of disability. Clinical tπals have yet to demonstrate therapeutic neuroprotection in ischemic stroke (i.e., stroke related to disruption of blood flow due to clot/thrombus formation) and spinal cord. Thrombolytic therapy (defined as use of an agent which causes dissolution or destruction of a thrombus) has many limitations, 20 but it remains the only approved form of treatment for acute ischemic stroke. Current strategies being tested in the clinic to inhibit ischemic brain injury target excitotoxic mechanisms, mtπc oxide associated neuronal damage, and ischemia associated neuronal cellular membrane damage Pre-climcal research strategies are also targeting anti-apoptotic and anti-inflammatory mechanisms. 25 The pathophysiological responses to traumatic brain injury or TBI (e.g , brain injury caused by, among other things, head accidents and head wounds) are similar in many respects to those of stroke and similar approaches are being taken to develop therapeutics for the treatment of TBI Whether or not a stroke is caused by ischemic oi hemorrhagic mechanisms can be determined by a CAT scan or other clinical procedure 30 and the mode of subsequent treatment will be dependent upon the results of this screening. Cellular adhesion and trafficking across the vascular interface plays an essential role in both physiological and pathophysiological processes of acute brain injury Of particular interest in the pathology of ischemic brain injury are polymorphonuclear leukocytes and T cells, which have been implicated in the development of brain damage after experimental stroke (Garcia et al 1994, Am. J. Pathol. 144:188; Becker et al, 1997 PNAS 94:10873). Cellular infiltration into the brain is thought to occur after brain injury and may contribute to disease progression. Thus, secondary brain damage (eg. hemorrhagic transformation, cerebral vasospasm) may also result from an acute brain injury in a subject. Spinal cord injury (SCI), like TBI occurs in a young healthy population but shares many pathological similarities to the changes occuring in the brain after a stroke. In light of such common mechanisms similar therapeutic approaches as those for stroke and TBI are being developed for the treatment of SCI. Cell-cell or cell-matrix interactions are mediated through several families of cell adhesion molecules, one such family of which includes the integrins. Integrins are structurally and functionally related glycoproteins consisting of various alpha (alphal, alpha 2, up to alpha 11 at present) and beta (beta 1 and beta 7) heterodimeric transmembrane receptor domains found in various combinations on virtually every mammalian cell type, (for reviews see: E. C. Butcher, Cell, 67, 1033 (1991); D. Cox et al., "The Pharmacology of the Integrins." Medicinal Research Rev. Vol. 195 (1994) and V. W. Engleman et al., "Cell Adhesion Integrins as Pharmaceutical Targets" in Ann, Revs.Medicinal Chemistry, Vol. 31, J. A. Bristol, Ed.; Acad. Press, NY, 1996, p. 191). Two alpha4 subunit containing integrins have been described and are designated alpha4betal (VLA-4) and alpha4beta7. Previous experiments showed upregulation of the alpha4betal and alpha4beta7 counter receptor VCAM-1 in the brain after ischemic injury, but no data demonstrating a functional role in the disease were reported (Jander et al, 1996, J. Neurolmmunol 70: 75). VLA-4 and alpha4beta7 are expressed on mononuclear leukocytes (see Lobb and Adams, 1994; _/. Clin. Invest. 94: 1722). It would be useful to develop methods of antagonizing members of the integrin family in this context. Further, it would be useful to develop a therapeutic modality for stroke that is efficacious whether the injury is ischemic or hemorrhagic. Summary of the Invention Until the present disclosure the pathological role of alpha4 subunit containing- integrins in CNS injury (e.g., cerebral ischemia) had not been defined. The present invention relates in part to the protective effect of inhibiting alpha4 subunit containing integrins in a rat model of focal cerebral ischemia. The present invention is drawn to methods to treat CNS injury, such as stroke, using inhibitors of alpha4betal and/or alpha4beta7 One aspect of the invention is a method to treat acute CNS injury in a patient in need of such treatment, compπsing administration of an alpha4 subunit containing mtegπn antagonist Another aspect is a method which includes further administering a pharmacological agent to the patient Preferably, the acute CNS injury is stroke, traumatic bram injury or spinal cord ιnjur> In some embodiments, the stroke is ischemic or hemorrhagic stroke The pharmacological agent may be a thrombolytic agent such as tissue plasminogen activator or urok ase or it may be a neuroprotective agent or anti- mflammatory agent In certain aspects of the invention, the neuroprotective agent is an antagonist of a receptor, the receptor selected from the group consisting of N-Methyl- D aspartate receptor (NMD A), α-amιno-3-hydroxy-5-methyl-4-ιsoxazolepropπonιc acid receptor (AMPA), glycine receptor, calcium channel receptor, bradykmm B2 receptor and sodium channel receptor In other aspects of the invention, the anti- mflammatory agent is selected from the group consisting of ιnterleukιn-1, and tumor necrosis factor family members The neuroprotective agent may also be an agonist of a receptor, the receptor selected from the group consisting of: the bradykmm B 1 receptor, γ-ammo butyπc acid (GAB A) receptor, and Adenos e Al receptor The invention further relates to a method to treat secondary bram damage resulting from an ischemic insult in a patient in need of such treatment, compπsing administration of an inhibitor of an α4 subunit containing mtegπn It is an object of the present invention to provide a method to treat ischemic oi hemorrhagic stroke using an inhibitor of the alpha4 subunit containing integπns alpha4betal or alpha4beta7 alone or together as the therapeutic agent, or alone oi together in combination with other therapeutic agents It is an object of the present invention to provide a method to treat traumatic bram injury using an inhibitor of the alpha4 subunit containing integπns alpha4betal oi alpha4beta7 alone or together as the therapeutic agent, or alone or together in combination with other therapeutic agents It is an object of the present invention to provide a method to treat spinal cord injury using an inhibitor of the alpha 4 subunit containing integπns alpha4betal or alpha4 beta7 alone or together as the therapeutic agent, or alone or together in combination with othei therapeutic agents It is a further object of this invention to provide a method to treat secondary bra damage occuπng as a consequence of a pπmary ischemic insult (eg. Hemorrhagic transformation, cerebral vasospasm) using an mhibitior of the alpha4 subunit containing integπns alpha4betal or alpha4beta7 alone or together as the therapeutic agent, or alone or together in combination with other therapeutic agents Brief description of drawings Figure 1A depicts a graph of mfarct volume (mm J ) in cortical and subcortical regions of the brams of Sprague Dawley rats after treatment with hoe 140 (300ng/kg/mιn) and vehicle control. Figure IB depicts a graph of infarct volume (mm') in cortical and subcortical regions of the brains of spontaneously hypertensive rats after treatment with hoe 140 (300 ng/kg/mm) and vehicle control. Figure 2A depicts a graph of infarct volume (mm J ) in cortical and subcortical regions of the brams of Sprague Dawley rats after treatment with antι-rat-alpha4 antibody (TA- 2, 2.5 mg/kg) and isotype control antibody. Figure 2B depicts a graph of infarct volume (mm 3 ) in cortical and subcortical regions of the brams of spontaneously hypertensive rats after treatment with antι-rat-alpha4 antibody (TA-2, 2.5 mg/kg) and isotype control antibody. Detailed Description of the Invention I. Definitions In order to more clearly and concisely point out the subject matter of the claimed invention, the following definitions are provided for specific terms used in the following wπtten descπption and appended claims. The invention will now be descπbed with reference to the following detailed descπption of which the following definitions are included. The integπn very late antigen (VLA) superfamily is made up of structurally and functionally related glycoproteins consisting of (alpha and beta) heterodimeπc, transmembrane receptor molecules found in vaπous combinations on nearly every mammalian cell type (for reviews see: E C. Butcher, Cell, 67, 1033 (1991), D. Cox et al., "The Pharmacologv of the Integπns " Medicinal Research Rev. (1994) and V. W. Engleman et al., 'Cell Adhesion Integπns as Pharmaceutical Targets. 'm Ann Report in Medicinal Chemistry. Vol. 31, J. A. Bπstol, Ed.; Acad. Press, NY, 1996, p. 191). Integπns of the VLA family include (at present) VLA-1, -2, -3, -4, -5, -6, -9, and -11 in which each of the molecules compπse a βl chain non- covalently bound to an alpha chain, (αl, 2, α3, α4, α5, α6 and the like), respectively. Alpha 4 beta 1 (oclβl) integπn is a cell-surface receptor for VCAM-1, fibronectm and possibly other ligands (the latter ligands individually and collectively referred to as "alpha4 hgand(s)") The term α4βl integπn ("VLA-4" or "a4bl" or "a4bl integπn", used interchangeably) herein thus refers to polypeptides which are capable of binding to VCAM-1 and members of the extracellular matπx proteins, most particularly fibronectm, or homologs or fragments thereof, although it will be appreciated by workers of ordinary skill in the art that other ligands for VLA-4 may exist and can be analyzed using conventional methods Nevertheless, it is known that the alpha4 subunit will associate with other beta subunits besides betal so that we may define the term "alpha (I) 4 integπn" or "alpha (I) 4 subunit-contaimng integπn" as being those integnns whose alpha4 subunit associates with one or another of the beta subunits Another example of an "alpha4" integπn besides VLA4 is alpha4beta7 (See Lobb and Adams, supra). An integπn "antagonist" includes any compound that inhibits alpha4 subunit- contamng integπns from binding with an integπn ligand and/or receptor. Anti-integπn antibody or antibody homolog-contaimng proteins (discussed below) as well as other molecules such as soluble forms of the ligand proteins for mtegnns are useful. Soluble forms of the ligand proteins for alpha4 subunit-contaimng integπns include soluble VCAM-1, VCAM-1 fusion proteins, or bifunctional VCAM-1/Ig fusion proteins For example, a soluble form of an integπn ligand or a fragment thereof may be administered to bind to integπn, and preferably compete for an integπn binding site on cells, thereby leading to effects similar to the administration of antagonists such as anti- integπn (e.g., VLA-4) antibodies. In particular, soluble integπn mutants that bind ligand but do not elicit mtegπn-dependent signaling are included within the scope of the invention. Such mtegπn mutants can act as competitive inhibitors of wild type integπn protein and are considered "antagonists". Other antagonists used in the methods of the invention are "small molecules", as defined below. Also included within the invention are methods using molecules that antagonize the action of more than one alpha 4 subunit-contaimng integπn, such as small molecules or antibody homologs that antagonize both VLA-4 and alpha4 beta7 or other combinations of alpha4 subunit-contaimng mtegnns. Also included within the scope of the invention are methods using a combination of molecules such that the combination antagonizes the action of more than one integrin, such as methods using several small molecules or antibody homologs that in combination antagonize both VLA-4 and alpha4 beta7 or other combinations of alpha4 subunit-containing integrins. As discussed herein, certain integrin antagonists can be fused or otherwise conjugated to, for instance, an antibody homolog such as an immunoglobulin or fragment thereof and are not limited to a particular type or structure of an integrin or ligand or other molecule. Thus, for purposes of the invention, any agent capable of forming a chimeric protein (as defined below) and capable of binding to integrin ligands and which effectively blocks or coats VLA- 4 (e.g., VLA-4) integrin is considered to be an equivalent of the antagonists used in the examples herein. "Antibody homolog" includes intact antibodies consisting of immunoglobulin light and heavy chains linked via disulfide bonds. The term "antibody homolog" is also intended to encompass a protein comprising one or more polypeptides selected from immunoglobulin light chains, immunoglobulin heavy chains and antigen-binding fragments thereof which are capable of binding to one or more antigens (i.e., integrin or integrin ligand). The component polypeptides of an antibody homolog composed of more than one polypeptide may optionally be disulfide-bound or otherwise covalently crosslinked. Accordingly, therefore, "antibody homologs" include intact immunoglobulins of types IgA, IgG, IgE, IgD, IgM (as well as subtypes thereof), wherein the light chains of the immunoglobulin may be of types kappa or lambda. "Antibody homologs" also includes portions of intact antibodies that retain antigen- binding specificity, for example Fab fragments, Fab' fragments, F(ab')2 fragments, F(v) fragments, heavy and light chain monomers or dimers or mixtures thereof. "Humanized antibody homolog" is an antibody homolog, produced by recombinant DNA technology, in which some or all of the amino acids of a human immunoglobulin light or heavy chain that are not required for antigen binding have been substituted for the corresponding amino acids from a nonhuman mammalian immunoglobulin light or heavy chain. A "human antibody homolog" is an antibody homolog in which all the amino acids of an immunoglobulin light or heavy chain (regardless of whether or not they are required for antigen binding) are derived from a human source. As used herein, a "human antibody homolog" is an antibody homolog produced by recombinant DNA technology, in which all of the amino acids of an immunoglobulin light or heavy chain that are derived from a human source. An integrin "agonist" includes any compound that activates the integrin ligand. "Amino acid" is a monomeric unit of a peptide, polypeptide, or protein. There are twenty amino acids found in naturally occurring peptides, polypeptides and proteins, all of which are L-isomers. The term also includes analogs of the amino acids and D- isomers of the protein amino acids and their analogs. "Covalently coupled" - means that the specified moieties of the invention (e.g., PEGylated alpha 4 integrin antagonist, immunoglobulin fragment/ alpha 4 integrin antagonist) are either directly covalently bonded to one another, or else are indirectly covalently joined to one another through an intervening moiety or moieties, such as a spacer moiety or moieties. The intervening moiety or moieties are called a "coupling group". The term "conjugated" is used interchangeably with "covalently coupled". In this regard a "spacer" refers to a moiety that may be inserted between an amino acid or other component of an alpha4 integrin antagonist or fragment and the remainder of the molecule. A spacer may provide separation between the amino acid or other component and the rest of the molecule so as to prevent the modification from interfering with protein function and/or make it easier for the amino acid or other component to link with another moiety. "Expression control sequence"- a sequence of polynucleotides that controls and regulates expression of genes when operatively linked to those genes. "Expression vector"- a polynucleotide, such as a DNA plasmid or phage (among other common examples) which allows expression of at least one gene when the expression vector is introduced into a host cell. The vector may, or may not, be able to replicate in a cell. An "effective amount" of an agent of the invention is that amount which produces a result or exerts an influence on the particular condition being treated. "Functional equivalent" of an amino acid residue is (i) an amino acid having similar reactive properties as the amino acid residue that was replaced by the functional equivalent; (ii) an amino acid of an antagonist of the invention, the amino acid having similar properties as the amino acid residue that was replaced by the functional equivalent; (iii) a non-amino acid molecule having similar properties as the amino acid residue that was replaced by the functional equivalent. A first polynucleotide encoding a proteinaceous antagonist of the invention is "functionally equivalent" compared with a second polynucleotide encoding the antagonist protein if it satisfies at least one of the following conditions: (a): the "functional equivalent" is a first polynucleotide that hybπdizes to the second polynucleotide under standard hybπdization conditions and/or is degenerate to the first polynucleotide sequence. Most preferably, it encodes a mutant protein having the activity of an integπn antagonist protein, (b) the "functional equivalent" is a first polynucleotide that codes on expression for an ammo acid sequence encoded by the second polynucleotide The integπn antagonists used in the invention include, but are not limited to, the agents listed herein as well as their functional equivalents As used herein, the term "functional equivalent" therefore refers to an integπn antagonist or a polynucleotide encoding the integπn antagonist that has the same or an improved beneficial effect on the recipient as the mtegπn antagonist of which it is deemed a functional equivalent. As will be appreciated by one of ordinary skill in the art, a functionally equivalent protein can be produced by recombinant techniques, e.g., by expressing a "functionally equivalent DNA". Accordingly, the instant invention embraces integπn proteins encoded by naturally-occurπng DNAs, as well as by non-naturally-occurπng DNAs which encode the same protein as encoded by the naturally-occurπng DNA. Due to the degeneracy of the nucleotide coding sequences, other polynucleotides may be used to encode integπn protein. These include all, or portions of the above sequences which are altered by the substitution of different codons that encode the same amino acid residue withm the sequence, thus producing a silent change. Such altered sequences are regarded as equivalents of these sequences. For example, Phe (F) is coded for by two codons, TTC or TTT, Tyr (Y) is coded for by TAC or TAT and His (H) is coded for by CAC or CAT On the other hand, Tip (W) is coded for by a single codon. TGG Accordingly, it will be appreciated that for a given DNA sequence encoding a particular integπn there will be many DNA degenerate sequences that will code for it These degenerate DNA sequences are considered withm the scope of this invention The term "chimeπc" when referπng to an antagonist of the invention, means that the antagonist is composed of a linkage (chemical cross-linkage or covalent or other type) of two or more proteins having disparate structures and/or having disparate sources of oπgm. Thus, a chimeπc alpha 4 integπn antagonist may include one moiety that is an alpha 4 integπn antagonist or fragment and another moiety that is not an alpha 4 integπn antagonist A species of 'chimeπc' protein is a "fusion" or "fusion protein" which refers to a co-linear, covalent linkage of two or more proteins or fragments thereof via their individual peptide backbones, most preferably through genetic expression of a polynucleotide molecule encoding those proteins Thus, preferred fusion proteins are chimeπc proteins that include an alpha4 integπn antagonist or fragment covalently linked to a second moiety that is not an alpha 4 integπn antagonist Preferred fusion proteins of the invention may include portions of intact antibodies that retain antigen- bmding specificity, for example, Fab fragments, Fab' fragments, F(ab')2 fragments, F(v) fragments, heavy chain monomers or dimers, light chain monomers or dimers, dimers consisting of one heavy and one light chain, and the like The most preferred fusion proteins are chimeπc and compπse an integπn antagonist moiety fused or otherwise linked to all or part of the hinge and constant regions of an immunoglobulin light chain, heavy chain, or both Thus, this invention features a molecule which includes (1) an integπn antagonist moiety, (2) a second peptide, e g., one which increases solubility or in vivo life time of the integπn antagonist moiety, e g , a member of the immunoglobulin super family or fragment or portion thereof, e g., a portion or a fragment of IgG, e g , the human IgGl heavy chain constant region, e.g , CH2, CH3, and hinge regions Specifically, a "integπn antagonist/Ig fusion" is a protein compπsing a biologically active integπn antagonist molecule of the invention (e.g. a soluble VLA-4 ligand, or a biologically active fragment thereof linked to an N-terminus of an immunoglobulin chain wherein a portion of the N-termmus of the immunoglobulin is replaced with the integπn antagonist A species of integπn antagonist/Ig fusion is an "mtegπn /Fc fusion" which is a protein compπsing an integπn antagonist of the invention linked to at least a part of the constant domain of an immunoglobulin A preferred Fc fusion compπses a mtegπn antagonist of the invention linked to a fragment of an antibody containing the C terminal domain of the heavy immunoglobulin chains The term "fusion protein" also means an integπn antagonist chemically linked via a mono- or hetero- functional molecule to a second moiety that is not an integπn antagonist (resulting in a "chimeπc" molecule) and is made de novo from puπfied protein as descπbed below Thus, one example of a chemically linked, as opposed to recombinantly linked, chimeπc molecule that is a fusion protein may compπse (1) an alpha 4 integπn subunit targeting moiety, e g., a VCAM-1 moiety capable of binding to VLA-4) on the surface of VLA-4 beaπng cells, (2) a second molecule which increases solubility or in vivo life time of the targeting moiety, e.g., a polyalkylene glycol polymer such as polyethylene glycol (PEG) The alpha4 targeting moiety can be any naturally occurπng alpha4 ligand or fragment thereof, e g , a VCAM-1 peptide or a similar conservatively substituted amino acid sequence "Heterologous promoter"- as used herein is a promoter which is not naturally associated with a gene or a puπfied nucleic acid "Homology"- as used herein is synonymous with the term "identity" and refers to the sequence similaπty between two polypeptides, molecules, or between two nucleic acids When a position in both of the two compared sequences is occupied by the same base or ammo acid monomer subunit (for instance, if a position in each of the two DNA molecules is occupied by adenme, or a position in each of two polypeptides is occupied by a lysme), then the respective molecules are homologous at that position The percentage homology between two sequences is a function of the number of matching or homologous positions shared by the two sequences divided by the number of positions compared x 100 For instance, if 6 of 10 of the positions in two sequences are matched or are homologous, then the two sequences are 60% homologous By way of example, the DNA sequences CTGACT and CAGGTT share 50% homology (3 of the 6 total positions are matched) Generally, a compaπson is made when two sequences are aligned to give maximum homology. Such alignment can be provided using, for instance, the method of Needleman et al , J. Mol Biol 48- 443-453 (1970), implemented conveniently by computer programs descnbed in more detail below. Homologous sequences share identical or similar ammo acid residues, where similar residues are conservative substitutions for, or "allowed point mutations" of, corresponding ammo acid residues in an aligned reference sequence In this regard, a "conservative substitution" of a residue in a reference sequence are those substitutions that are physically or functionally similar to the corresponding reference residues, e g , that have a similar size, shape, electπc charge, chemical properties, including the ability to form covalent or hydrogen bonds, or the like Particularly preferred conservative substitutions are those fulfilling the cπteπa defined for an ' accepted point mutation" m Dayhoff et al , 5 Atlas of Protein Sequence and Structure, 5 Suppl 3, chapter 22 354-352, Nat Biomed Res Foundation, Washington, D C (1978) "Homology" and "identity" each refer to sequence similarity between two polypeptide sequences, with identity being a more stπct companson Homology and identity can each be determined by compaπng a position in each sequence which may be aligned for purposes of compaπson When a position in the compared sequence is occupied by the same amino acid residue, then the polypeptides can be referred to as identical at that position; when the equivalent site is occupied by the same ammo acid (e.g., identical) or a similar amino acid (e.g., similar m steπc and/or electronic nature), then the molecules can be refered to as homologous at that position. A percentage of homology or identity between sequences is a function of the number of matching or homologous positions shared by the sequences. An "unrelated" or "non-homologous" sequence shares less than 40 percent identity, though preferably less than 25 percent identity, with an AR sequence of the present invention Vaπous alignment algoπthms and/or programs may be used, including FASTA, BLAST or ENTREZ. FASTA and BLAST are available as a part of the GCG sequence analysis package (University of Wisconsin, Madison, Wis.), and can be used with, e.g , default settings. ENTREZ is available through the National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Md. In one embodiment, the percent identity of two sequences can be determined by the GCG program with a gap weight of 1, e.g., each am o acid gap is weighted as if it were a single am o acid or nucleotide mismatch between the two sequences. "Isolated" (used interchangeably with "substantially pure")- when applied to nucleic acid i.e., polynucleotide sequences that encode integπn antagonists, means an RNA or DNA polynucleotide, portion of genomic polynucleotide, cDNA or synthetic polynucleotide which, by virtue of its origin or manipulation: (i) is not associated with all of a polynucleotide with which it is associated in nature (e.g., is present in a host cell as an expression vector, or a portion thereof); or (n) is linked to a nucleic acid or other chemical moiety other than that to which it is linked in nature; or (in) does not occur in nature. By "isolated" it is further meant a polynucleotide sequence that is (1) amplified in vitro by, for example, polymerase chain reaction (PCR); (n) synthesized chemically; (m) produced recombinantly by cloning; or (iv) puπfied, as by cleavage and gel separation. Thus, "substantially pure nucleic acid" is a nucleic acid which is not immediately contiguous with one or both of the coding sequences with which it is normally contiguous in the naturally occurπng genome of the organism from which the nucleic acid is deπved. Substantially pure DNA also includes a recombinant DNA which is part of a hybπd gene encoding additional integnn sequences. Isolated" (used interchangeably with "substantially pure")- when applied to polypeptides means a polypeptide or a portion thereof which, by virtue of its oπgm or manipulation: (I) is present m a host cell as the expression product of a portion of an expression vector; or (n) is linked to a protein or other chemical moiety other than that to which it is linked in nature; or (iii) does not occur in nature, for example, a protein that is chemically manipulated by appending, or adding at least one hydrophobic moiety to the protein so that the protein is in a form not found in nature.. By "isolated" it is further meant a protein that is: (i) synthesized chemically; or (ii) expressed in a host cell and purified away from associated and contaminating proteins. The term generally means a polypeptide that has been separated from other proteins and nucleic acids with which it naturally occurs. Preferably, the polypeptide is also separated from substances such as antibodies or gel matrices (polyacrylamide) which are used to purify it. "Multivalent protein complex"- refers to a plurality of integrin antagonists (i.e., one or more). An anti-integrin antibody homolog or fragment may be cross-linked or bound to another antibody homolog or fragment. Each protein may be the same or different and each antibody homolog or fragment may be the same or different. "Mutant" - any change in the genetic material of an organism, in particular any change (i.e., deletion, substitution, addition, or alteration) in a wild type polynucleotide sequence or any change in a wild type protein. The term "mutein" is used interchangeably with "mutant". "Operatively linked"- a polynucleotide sequence (DNA, RNA) is operatively linked to an expression control sequence when the expression control sequence controls and regulates the transcription and translation of that polynucleotide sequence. The term "operatively linked" includes having an appropriate start signal (e.g., ATG) in front of the polynucleotide sequence to be expressed, and maintaining the correct reading frame to permit expression of the polynucleotide sequence under the control of the expression control sequence, and production of the desired polypeptide encoded by the polynucleotide sequence. A "pharmacological agent", is defined as one or more compounds or molecules or other chemical entities administered to a subject (in addition to the antagonists of the invention) that affect the action of the antagonist. The term "pharmacological agent' as used herein refers to such an agent(s) that are administered during "combination therapy" where the antagonist of the invention is administered either prior to, after, or simultaneously with, administration of one or more pharmacological agents. "Protein"- any polymer consisting essentially of any of the 20 amino acids. Although "polypeptide" is often used in reference to relatively large polypeptides, and "peptide" is often used in reference to small polypeptides, usage of these terms in the art overlaps and is vaπed. The term "protein" as used herein refers to peptides, proteins and polypeptides, unless otherwise noted. The terms "peptιde(s)", "protem(s)" and "polypeptιde(s)" are used interchangeably herein. The terms "polynucleotide sequence" and "nucleotide sequence" are also used interchangeably herein "Recombinant," as used herein, means that a protein is deπved from recombinant. mammalian expression systems. Since integπn is not glycosylated nor contains disulfide bonds, it can be expressed in most prokaryotic and eukaryotic expression systems. "Small molecule"- has the definition as in Section A2 The phrase "surface ammo acid" means any amino acid that is exposed to solvent when a protein is folded in its native form "Standard hybπdization conditions"- salt and temperature conditions substantially equivalent to 0.5 X SSC to about 5 X SSC and 65 ° C for both hybπdization and wash The term "standard hybπdization conditions" as used herein is therefore an operational definition and encompasses a range of hybπdization conditions. Higher stπngency conditions may, for example, include hybπdizmg with plaque screen buffer (0.2% polyvmylpyrrohdone, 0.2% Ficoll 400; 0.2% bovme serum albumin, 50 mM Tπs-HCl (pH 7.5); 1 M NaCl; 0.1% sodium pyrophosphate; 1 % SDS); 10% dextran sulfate, and 100 μg/ml denatured, sonicated salmon sperm DNA at 65 ° C for 12-20 hours, and washing with 75 mM NaCl/7.5 mM sodium citrate (0.5 x SSC)/1% SDS at 65° C Lower stπngency conditions may, for example, include hybπdizmg with plaque screen buffer, 10% dextran sulfate and 110 μg/ml denatured, sonicated salmon sperm DNA at 55 ° C for 12-20 hours, and washing with 300 mM NaCl/30mM sodium citrate (2.0 X SSC)/1% SDS at 55 ° C. See also Current Protocols in Molecular Biology, John Wiley & Sons, Inc. New York, Sections 6.3.1-6.3.6, (1989) A "therapeutic composition" as used herein is defined as compπsing the antagonists of the invention and other biologically compatible ingredients The therapeutic composition may contain excipients such as water, minerals and earners such as protein. An antagonist of the invention (and its therapeutic composition) is said to have "therapeutic efficacy," and an amount of the agent is said to be "therapeutically effective," if administration of that amount of the agent is sufficient to cause a clinically significant improvement m neurological recovery in a standard neurological test (Section IV) when administered to a subject (e.g., an animal model or human patient) after bram damage (eg cerebral ischemia or stroke). Practice of the present invention will employ, unless indicated otherwise, conventional techniques of cell biology, cell culture, molecular biology, microbiology, recombinant DNA, protein chemistry, pharmacology and immunology, which are within the skill of the art Such techniques are descnbed in the literature Unless stipulated otherwise, all references cited m the Detailed Descnption are incorporated herein by reference. II Descnption of the preferred Embodiments General We have discovered that inhibition of the α4 mtegnns; α4βl and/or α4β7 protects the brain against injury induced by acute insult Using a rat model of stroke caused by temporary occlusion of the middle cerebral artery we have demonstrated a significant reduction in brain infarction after treatment with an alpha 4 mtegnn antagonist. The relevance of animal models of stroke has been reviewed by Hunter et al (1996) Trends in Pharmacological Sciences 6:123. The rat model of reversible middle cerebral artery occlusion in both Sprague Dawley (SD) and Spontaneously Hypertensive Rats (SHRs) is widely viewed as the most clinically relevant of rodent stroke models. (Hunter et al (1996) Trends in Pharmacological Sciences 6: 123). A. Integrin Antagonists For the purposes of the invention an mtegnn antagonist can be an antagonist of any interaction between an tegnn and its cognate ligand or receptor such that the normal function induced by hgand-receptor interactions is altered (i.e., prevented or slowed or otherwise modified). One preferred embodiment of an mtegnn antagonist is an antagonist of interactions of alpha4 mtegnns with their ligands, such as the VCAM- l/VLA-4 interaction. This is an agent, e.g., a polypeptide or other molecule, which can inhibit or block VCAM-1 and/or VLA-4-medιated binding or which can otherwise modulate VCAM-1 and/or VLA-4 function, e.g., by inhibiting or blocking VLA -4- ligand mediated VLA-4 signal transduction or VCAM-1-lιgand mediated VCAM-1 signal transduction and which is effective in the treatment of acute bram injury, preferably in the same manner as are antι-VLA-4 antibodies. An antagonist of the VCAM-1/ VLA-4 interaction is an agent which has one or more of the following properties: (1) it coats, or binds to, VLA-4 on the surface of a VLA-4 beanng cell (e.g., an endothehal cell) with sufficient specificity to inhibit a VLA-4-hgand/VLA-4 interaction, e.g., the VCAM-l/VLA-4 interaction, (2) it coats, or binds to, VLA-4 on the surface of a VLA-4 beaπng cell (i.e., a lymphocyte) with sufficient specificity to modify, and preferably to inhibit, transduction of a VLA -4- mediated signal e.g., VLA-4/VCAM-1 -mediated signaling; (3) it coats, or binds to, a VLA-4-hgand, (e.g., VCAM- 1) on endothehal cells with sufficient specificity to inhibit the VLA- 4 /VCAM-1 interaction, (4) it coats, or binds to, a VLA-4-hgand (e g , VCAM- 1) with sufficient specificity to modify, and preferably to inhibit, transduction of VLA-4-lιgand mediated VLA-4 signaling, e.g , VCAM-1 -mediated VLA-4 signaling In prefened embodiments the antagonist has one or both of properties 1 and 2. In other preferred embodiments the antagonist has one or both of properties 3 and 4 Moreover, more than one antagonist can be administered to a patient, e.g., an agent which binds to VLA-4 can be combined with an agent which binds to VCAM-1 As discussed herein, the antagonists used in methods of the invention are not limited to a particular type or structure of molecule so that, for purposes of the invention, any agent capable of binding to alpha4 integπns (e.g., VLA-4) on the surface of cells or to an alpha4 ligand such as VCAM-1 on the surface of alpha4 ligand-bearmg cells) and which effectively blocks or coats alpha 4 mtegnn (e.g., VLA-4) or alpha 4 ligand (e.g., VCAM-1), called an "alpha4 mtegnn binding agent" and "alpha4 mtegnn ligand binding agent" respectively), is considered to be an equivalent of the antagonists used in the examples herein. For example, antibodies or antibody homologs (discussed below) as well as soluble forms of the natural binding proteins for VLA-4 and VCAM-1 are useful Soluble forms of the natural binding proteins for VLA-4 include soluble VCAM-1 peptides, VCAM-1 fusion proteins, bifunctional VCAM-1/Ig fusion proteins (e.g. "chimeπc" molecules, discussed above), fibronectm, fibronectm having an alternatively spliced non-type III connecting segment, and fibronectm peptides containing the ammo acid sequence EILDV or a similar conservatively substituted ammo acid sequence Soluble forms of the natural binding proteins for VCAM-1 include soluble VLA-4 peptides, VLA-4 fusion proteins, bifunctional VLA-4/Ig fusion proteins and the like As used herein, a "soluble VLA-4 peptide" or a "soluble VCAM-1 peptide" is an VLA- 4 or VCAM-1 polypeptide incapable of anchonng itself in a membrane. Such soluble polypeptides include, for example, VLA-4 and VCAM polypeptides that lack a sufficient portion of their membrane spanning domain to anchor the polypeptide or are modified such that the membrane spanning domain is non-functional. These binding agents can act by competing with the cell-surface binding protein for VLA-4 or by otherwise alteπng VLA-4 function. For example, a soluble form of VCAM-1 (see, e.g , Osborn et al. 1989, Cell, 59- 1203-1211) or a fragment thereof may be administered to bind to VLA-4, and preferably compete for a VLA-4 binding site on VCAM-1-beaπng cells, thereby leading to effects similar to the administration of antagonists such as small molecules or antι-VLA-4 antibodies. 1. Anti-Integnn Antibody Homologs In other preferred embodiments, the antagonists used in the method of the invention to bind to, including block or coat, cell-surface alpha4 mtegnn (such as VLA- 4 or alpha4 beta7) and/or cell surface ligand for alpha 4 mtegnn (such as VCAM-1) is an an ti- VLA-4 and/or antι-VCAM-1 monoclonal antibody or antibody homolog, as defined previously. Preferred antibodies and homologs for treatment, in particular for human treatment, include human antibody homologs, humanized antibody homologs, chimeπc antibody homologs, Fab, Fab', F(ab')2 and F(v) antibody fragments, and monomers or dimers of antibody heavy or light chains or mixtures thereof Monoclonal antibodies against VLA-4 are a prefened binding agent in the method of the invention 2. Small Molecule Integnn Antagonists The term " small molecule" mtegnn antagonist refers to chemical agents (i.e., organic molecules) capable of disrupting the mtegnn/mtegπn ligand interaction by, for instance, blocking VLA-4/VCAM interactions by binding VLA-4 on the surface of cells or binding VCAM-1 on the surface of cells. Such small molecules may also bind respective VLA-4 and VCAM-1 receptors. VLA-4 and VCAM-1 small molecule inhibitors may themselves be peptides, semi-peptidic compounds or non-peptidic compounds, such as small organic molecules that are antagonists of the VCAM- l/VLA-4 interaction. A "small molecule", as defined herein, is not intended to encompass an antibody or antibody homolog The molecular weight of exemplary small molecules is generally less than 1000. For instance, small molecules such as ohgosacchaπdes that mimic the binding domain of a VLA-4 ligand and fit the receptor domain of VLA-4 may be employed. (See, J.J. Devlin et al., 1990, Science 249 400-406 (1990), J.K. Scott and G.P. Smith, 1990, Science 249: 386-390, and U.S. Patent 4,833,092 (Geysen), all incorporated herein by reference). Conversely, small molecules that mimic the binding domain of a VCAM-1 ligand and fit the receptor domain of VCAM-1 may be employed. Examples of other small molecules useful in the invention can be found m Komoπya et al. ("The Minimal Essential Sequence for a Major Cell Type-Specific Adhesion Site (CS1) Withm the Alternatively Spliced Type III Connecting Segment Domain of Fibronectm Is Leucme-Aspartic Acid-Valme", J. Biol. Chem., 266 (23), pp. 15075-79 (1991)) They identified the minimum active ammo acid sequence necessary to bind VLA-4 and synthesized a vanety of overlapping peptides based on the ammo acid sequence of the CS-1 region (the VLA-4 binding domain) of a particular species of fibronectm. They identified an 8-ammo acid peptide, Glu-Ile-Leu-Asp-Val- Pro-Ser-Thr, as well as two smaller overlapping pentapeptides, Glu-Ile-Leu-Asp-Val and Leu-Asp-Val-Pro-Ser, that possessed inhibitory activity against fibronectin- dependent cell adhesion. Certain larger peptides containing the LDV sequence were subsequently shown to be active in vivo (T A Ferguson et al., "Two Integπn Binding Peptides Abrogate T-cell-Mediated Immune Responses In Vivo", Proc. Natl. Acad. Sci USA, 88, pp. 8072-76 (1991), and S. M. Wahl et al., "Synthetic Fibronectm Peptides Suppress Arthπtis in Rats by Interrupting Leukocyte Adhesion and Recruitment", J Clin. Invest., 94, pp. 655-62 (1994)). A cyclic pentapeptide, Arg-Cys-Asp-TPro-Cys (wherein TPro denotes 4-thιoprolme), which can inhibit both VLA-4 and VLA-5 adhesion to fibronectm has also been descnbed. (See, e.g., D.M. Nowhn et al. "A Novel Cyclic Pentapeptide Inhibits Alpha4Betal Integnn-mediated Cell Adhesion", J Biol. Chem., 268(27), pp. 20352-59 (1993); and PCT publication PCT/US91/04862) This pentapeptide was based on the tπpeptide sequence Arg-Gly-Asp from fibronectm which had been known as a common motif in the recognition site for several extracellular-matnx proteins. Examples of other VLA-4 inhibitors have been reported, for example, in Adams et al. "Cell Adhesion Inhibitors". PCT US97/13013, descπbing linear peptidyl compounds containing beta-amino acids which have cell adhesion inhibitory activity. International patent applications WO 94/15958 and WO 92/00995 descnbe cyclic peptide and peptidomimetic compounds with cell adhesion inhibitor} activity International patent applications WO 93/08823 and WO 92/08464 descnbe guanidmyl-, urea- and thiourea-containmg cell adhesion inhibitory compounds United States Patent No. 5,260,277 descnbes guanidmyl cell adhesion modulation compounds Other peptidyl antagonists of VLA-4 have been described in D. Y. Jackson et al., "Potent α4βl peptide antagonists as potential anti-mflammatory agents', J. Med. Chem.. 40.3359 (1997); H. Shroff et al., 'Small peptide inhibitors of oc4β7 mediated MadCAM-1 adhesion to lymphocytes", Bio Med. Chem Lett., 1 2495 (1996); U.S Patent 5,510,332, PCT Publications WO 98/53814, W097/03094, W097/02289, W096/40781, W096/22966,W096/20216, W096/01644, W096106108, and W095/15973, and others Such small molecule agents may be produced by synthesizing a plurality of peptides (e g., 5 to 20 ammo acids in length), semi-peptidic compounds or non- peptidic, organic compounds, and then screening those compounds for their ability to inhibit the VLA-4/VCAM interaction See generally U.S Patent No. 4,833,092, Scott and Smith, "Searching for Peptide Ligands with an Epitope Library", Science, 249, pp 386-90 (1990), and Devlm et al., "Random Peptide Libranes A Source of Specific Protein Binding Molecules", Science, 249, pp 40407 (1990) B. Methods of Making Anti-Integrin Antibody Homologs The prefened mtegπn antagonists contemplated herein can be expressed from mtact or truncated genomic or cDNA or from synthetic DNAs in prokaryotic or eukaryotic host cells The dimeπc proteins can be isolated from the culture media and/or refolded and dimenzed in vitro to form biologically active compositions. Heterodimers can be formed in vitro by combining separate, distinct polypeptide chains. Alternatively, heterodimers can be formed in a single cell by co-expressing nucleic acids encoding separate, distinct polypeptide chains. See, for example, WO93/09229, or U.S. Pat. No. 5,411,941, for several exemplary recombinant heterodimer protein production protocols. Cunently preferred host cells include, without limitation, prokaryotes including E. coli, or eukaryotes including yeast, Saccharomyces, insect cells, or mammalian cells, such as CHO, COS or BSC cells One of ordinary skill in the art will appreciate that other host cells can be used to advantage. Detailed descnptions of the proteins useful in the practice of this invention, including how to make, use and test them for chondrogenic activity, are disclosed in numerous publications, including U.S Pat. Nos. 5,266,683 and 5,011,691, the disclosures of which are herein incorporated by reference The technology for producing monoclonal antibody homologs is well known Bπefly, an immortal cell line (typically myeloma cells) is fused to lymphocytes (typically splenocytes) from a mammal immunized with whole cells expressing a given antigen, e.g., VLA-4, and the culture supernatants of the resulting hybndoma cells are screened for antibodies against the antigen. See, generally, Kohler et at., 1975, Nature, 265: 295-297. Immunization may be accomplished using standard procedures.. The unit dose and immunization regimen depend on the species of mammal immunized, its immune status, the body weight of the mammal, etc. Typically, the immunized mammals are bled and the serum from each blood sample is assayed for particular antibodies using appropriate screening assays. For example, anti-VLA-4 antibodies may be identified by immunoprecipitation of 1251-labeled cell lysates from VLA-4- expressing cells. (See, Sanchez-Madrid et al. 1986, Eur. J. Immunol., 16: 1343-1349 and Hemler et al. 1987, J. Biol. Chem., 262, 11478-11485). Anti-VLA-4 antibodies may also be identified by flow cytometry, e.g., by measuring fluorescent staining of Ramos cells incubated with an antibody believed to recognize VLA-4 (see, Elices et al., 1990 Cell, 60: 577-584). The lymphocytes used in the production of hybridoma cells typically are isolated from immunized mammals whose sera have already tested positive for the presence of anti-VLA-4 antibodies using such screening assays. Typically, the immortal cell line (e.g., a myeloma cell line) is derived from the same mammalian species as the lymphocytes. Preferred immortal cell lines are mouse myeloma cell lines that are sensitive to culture medium containing hypoxanthine, arninopterin and thymidine ("HAT medium"). Typically, HAT-sensitive mouse myeloma cells are fused to mouse splenocytes using 1500 molecular weight polyethylene glycol ("PEG 1500"). Hybridoma cells resulting from the fusion are then selected using HAT medium, which kills unfused and unproductively fused myeloma cells (unfused splenocytes die after several days because they are not transformed). Hybridomas producing a desired antibody are detected by screening the hybridoma culture supernatants. For example, hybridomas prepared to produce anti-VLA-4 antibodies may be screened by testing the hybridoma culture supernatant for secreted antibodies having the ability to bind to a recombinant alρha4-subunit-expressing cell line (see, Elices et al., supra). To produce anti-VLA-4 antibody homologs that are intact immunoglobulins, hybridoma cells that tested positive in such screening assays were cultured in a nutrient medium under conditions and for a time sufficient to allow the hybridoma cells to secrete the monoclonal antibodies into the culture medium. Tissue culture techniques and culture media suitable for hybridoma cells are well known. The conditioned hybridoma culture supernatant may be collected and the anti-VLA4 antibodies optionally further purified by well-known methods. Alternatively, the desired antibody may be produced by injecting the hybridoma cells into the peritoneal cavity of an unimmunized mouse. The hybridoma cells proliferate in the peritoneal cavity, secreting the antibody which accumulates as ascites fluid The antibody may be harvested by withdrawing the ascites fluid from the peπtoneal cavity with a syπnge. Several mouse anti-VLA-4 monoclonal antibodies have been previously descnbed. See, e.g . Sanchez-Madπd et al., 1986, supra; Hemler et al , 1987, supra; Puhdo et al , 1991. J Biol Chem., 266 (16), 10241-10245); Issekutz and Wykretowicz, 1991, J. Immunol., 147: 109 (TA-2 mab) These anti-VLA-4 monoclonal antibodies and other anti-VLA-4 antibodies (e.g., U.S Patent 5,888,507- Biogen, Inc and references cited therein) capable of recognizing the alpha and/or beta chain of VLA-4 will be useful in the methods of treatment according to the present invention AntιVLA-4 antibodies that will recognize the VLA-4 alpha4 chain epitopes involved in binding to VCAM-1 and fibronectm ligands (l e., antibodies which can bind to VLA-4 at a site involved in ligand recognition and block VCAM-1 and fibronectm binding) are prefened. Such antibodies have been defined as B epitope-specific antibodies (Bl or B2) (Puhdo et al., 1991, supra) and are also anti-VLA-4 antibodies according to the present invention. Fully human monoclonal antibody homologs against VLA-4 are another preferred binding agent which may block or coat VLA-4 ligands in the method of the invention. In their mtact form these may be prepared using in vitro-pπmed human splenocytes, as descnbed by Boerner et al., 1991, J. Immunol., 147, 86-95. Alternatively, they may be prepared by repertoire cloning as descnbed by Persson et al, 1991, Proc. Nat. Acad. Sci. USA, 88: 2432-2436 or by Huang and Stollar, 1991, J Immunol. Methods 141, 227-236. U.S. Patent 5,798,230 (Aug. 25, 1998, "Process foi the preparation of human monoclonal antibodies and their use") who descnbe preparation of human monoclonal antibodies from human B cells. According to this process, human antibody-producing B cells are immortalized by infection with an Epstem-Bare virus, or a deπvative thereof, that expresses Epstein-Ban virus nuclear antigen 2 (EBNA2). EBNA2 function, which is required for immortalization, is subsequently shut off, which results in an increase in antibody production In yet another method for producing fully human antibodies, United States Patent 5,789,650 (Aug 4, 1998, " Transgemc non-human animals for producing heterologous antibodies") descnbes transgemc non-human animals capable of producing heterologous antibodies and transgemc non-human animals having inactivated endogenous immunoglobulin genes. Endogenous immunoglobulin genes are suppressed by antisense polynucleotides and/or by antiserum directed against endogenous lmmunoglobuhns. Heterologous antibodies are encoded by immunoglobulin genes not normally found in the genome of that species of non-human animal. One or more transgenes containing sequences of unreananged heterologous human immunoglobulin heavy chains are introduced into a non-human animal thereb\ forming a transgemc animal capable of functionally reananging transgemc immunoglobulin sequences and producing a repertoire of antibodies of vanous isotypes encoded by human immunoglobulin genes. Such heterologous human antibodies are produced in B-cells which are thereafter immortalized, e g , by fusing with an immortalizing cell line such as a myeloma or by manipulating such B-cells by other techniques to peφetuate a cell line capable of producing a monoclonal heterologous. fully human antibody homolog. Large nonimmumzed human phage display hbranes may also be used to isolate high affinity antibodies that can be developed as human therapeutics using standard phage technology (Vaughan et al, 1996) Yet another prefened binding agent which may block or coat mtegnn ligands the method of the invention is a humanized recombinant antibody homolog having anti- mtegπn specificity. Following the early methods for the preparation of true "chimenc antibodies" (where the entire constant and entire vaπable regions are deπved from different sources), a new approach was descnbed m EP 0239400 (Winter et al.) whereby antibodies are altered by substitution (withm a given vaπable region) of their complementaπty determining regions (CDRs) for one species with those from another This process may be used, for example, to substitute the CDRs from human heavy and light chain Ig vaπable region domains with alternative CDRs from munne vaπable region domains. These altered Ig vaπable regions may subsequently be combined with human Ig constant regions to created antibodies which are totally human in composition except for the substituted munne CDRs. Such CDR-substituted antibodies would be predicted to be less likely to elicit an immune response in humans compared to true chimeπc antibodies because the CDR-substituted antibodies contain considerably less non-human components. The process for humanizing monoclonal antibodies via CDR "grafting" has been termed "reshaping". (Riechmann et al., 1988, Nature 332, 323-327; Verhoeyen et al., 1988, Science 239, 1534-1536). Typically, complementaπty determining regions (CDRs) of a munne antibody are transplanted onto the conespondmg regions m a human antibody, since it is the CDRs (three m antibody heavy chains, three in light chains) that are the regions of the mouse antibody which bind to a specific antigen. Transplantation of CDRs is achieved by genetic engmeeπng whereby CDR DNA sequences are determined by cloning of munne heavy and light chain vanable (V) region gene segments, and are then transferred to corresponding human V regions by site directed mutagenesis. In the final stage of the process, human constant region gene segments of the desired isotype (usually gamma I for CH and kappa for CL) are added and the humanized heavy and light chain genes are co-expressed in mammalian cells to produce soluble humanized antibody The transfer of these CDRs to a human antibody confers on this antibody the antigen binding properties of the oπginal munne antibody. The six CDRs in the munne antibody are mounted structurally on a V region "framework" region The reason that CDR-graft g is successful is that framework regions between mouse and human antibodies may have very similar 3-D structures with similar points of attachment for CDRS, such that CDRs can be interchanged. Such humanized antibody homologs may be prepared, as exemplified in Jones et al., 1986, Nature 321, 522-525; Riechmann, 1988, Nature 332, 323-327; Queen et al., 1989, Proc. Nat. Acad. Sci. USA 86, 10029; and Orlandi et al., 1989, Proc. Nat. Acad. Sci. USA 86, 3833. Nonetheless, certain ammo acids within framework regions are thought to interact with CDRs and to influence overall antigen binding affinity. The direct transfer of CDRs from a munne antibody to produce a recombinant humanized antibody without any modifications of the human V region frameworks often results in a partial or complete loss of binding affinity. In a number of cases, it appears to be cntical to alter residues in the framework regions of the acceptor antibody in order to obtain binding activity. Queen et al., 1989 (supra) and WO 90/07861 (Protein Design Labs) have descnbed the preparation of a humanized antibody that contains modified residues in the framework regions of the acceptor antibody by combining the CDRs of a munne MAb (anti-Tac) with human immunoglobulin framework and constant regions. They have demonstrated one solution to the problem of the loss of binding affinity that often results from direct CDR transfer without any modifications of the human V region framework residues; their solution involves two key steps. First, the human V framework regions are chosen by computer analysts for optimal protein sequence homology to the V region framework of the oπginal munne antibody, in this case, the anti-Tac MAb In the second step, the tertiary structure of the munne V region is modelled by computer in order to visualize framework amino acid residues which are likely to interact with the munne CDRs and these munne amino acid residues are then supeπmposed on the homologous human framework See also U.S Patents 5,693,762, 5,693,761, 5,585,089, and 5,530,101 (Protein Design Labs) One may use a different approach (Tempest et al , 1991, Biotechnology 9, 266- 271) and utilize, as standard, the V region frameworks denved from NEWM and REI heavy and light chains respectively for CDR-graftmg without radical introduction of mouse residues. An advantage of using the Tempest et al., approach to construct NEWM and REI based humanized antibodies is that the 3dιmensιonal structures of NEWM and REI vaπable regions are known from x-ray crystallography and thus specific interactions between CDRs and V region framework residues can be modeled Regardless of the approach taken, the examples of the initial humanized antibody homologs prepared to date have shown that it is not a straightforward process However, even acknowledging that such framework changes may be necessary, it is not possible to predict, on the basis of the available pnor art, which, if any, framework residues will need to be altered to obtain functional humanized recombinant antibodies of the desired specificity. Results thus far indicate that changes necessary to preserve specificity and/or affinity are for the most part unique to a given antibody and cannot be predicted based on the humanization of a different antibody. Certain alpha4 subunit-contaimng mtegnn antagonists useful m the present invention include chimeπc and humanized recombinant antibody homologs ( i.e., intact immunoglobulins and portions thereof) with B epitope specificity that have been prepared and are descnbed in U.S. Patent 5,932,214( mab HP1/2) The starting matenal for the preparation of chimeπc (mouse Vaπable - human Constant) and humanized anti-integnn antibody homologs may be a munne monoclonal anti-mtegnn antibody as previously descnbed, a monoclonal anti-mtegnn antibody commercially available (e.g., HP2/1, Amae International, Inc., Westbrook, Maine), or a monoclonal anti-mtegnn antibody prepared in accordance with the teaching herein. Other prefeπed humanized antι-VLA4 antibody homologs are descnbed by Athena Neurosciences, Inc in PCT/US95/01219 (27 July 1995) and U.S. Patent 5,840,299. These humanized anti-VLA-4 antibodies compnse a humanized light chain and a humanized heavy chain. The humanized light chain compnses three complementanty determining regions (CDRI, CDR2 and CDR3) having amino acid sequences from the corresponding complementaπty determining regions of a mouse 21- 6 immunoglobulin light chain, and a variable region framework from a human kappa light chain variable region framework sequence except in at least position the amino acid position is occupied by the same amino acid present in the equivalent position of the mouse 21.6 immunoglobulin light chain variable region framework. The humanized heavy chain comprises three complementarity determining regions (CDRl, CDR2 and CDR3) having amino acid sequences from the corcesponding complementarity determining regions of a mouse 21-6 immunoglobulin heavy chain, and a variable region framework from a human heavy chain variable region framework sequence except in at least one position the amino acid position is occupied by the same amino acid present in the equivalent position of the mouse 21-6 immunoglobulin heavy chain variable region framework. C. Production of Fragments and Analogs Fragments of an isolated alpha4 integrin antagonists (e.g., fragments of antibody homologs described herein) can also be produced efficiently by recombinant methods, by proteolytic digestion, or by chemical synthesis using methods known to those of skill in the art. In recombinant methods, internal or terminal fragments of a polypeptide can be generated by removing one or more nucleotides from one end (for a terminal fragment) or both ends (for an internal fragment) of a DNA sequence which encodes for the isolated hedgehog polypeptide. Expression of the mutagenized DNA produces polypeptide fragments. Digestion with "end nibbling" endonucleases can also generate DNAs which encode an array of fragments. DNAs which encode fragments of a protein can also be generated by random shearing, restriction digestion, or a combination or both. Protein fragments can be generated directly from intact proteins. Peptides can be cleaved specifically by proteolytic enzymes, including, but not limited to plasmin, thrombin, trypsin, chymotrypsin, or pepsin. Each of these enzymes is specific for the type of peptide bond it attacks. Trypsin catalyzes the hydrolysis of peptide bonds in which the carbonyl group is from a basic amino acid, usually arginine or lysine. Pepsin and chymotrypsin catalyse the hydrolysis of peptide bonds from aromatic amino acids, such as tryptophan, tyrosine, and phenylalanine. Alternative sets of cleaved protein fragments are generated by preventing cleavage at a site which is suceptible to a proteolytic enzyme. For instance, reaction of the ε-amino acid group of lysine with ethyltrifluorothioacetate in mildly basic solution yields blocked amino acid residues whose adjacent peptide bond is no longer susceptible to hydrolysis by trypsin. Proteins can be modified to create peptide linkages that are susceptible to proteolytic enzymes. For instance, alkylation of cysteme residues with β-haloethylammes yields peptide linkages that are hydrolyzed by trypsin (Lmdley, (1956) Nature 178, 647). In addition, chemical reagents that cleave peptide chains at specific residues can be used For example, cyanogen bromide cleaves peptides at methionine residues (Gross and Witkip, (1961) J Am Chem. Soc. 83, 1510) Thus, by treating proteins with vanous combmations of modifiers, proteolytic enzymes and/or chemical reagents, the proteins may be divided into fragments of a desired length with no overlap of the fragments, oi divided into overlapping fragments of a desired length Fragments can also be synthesized chemically using techniques known m the art such as the Merπfield solid phase F moc or t-Boc chemistry Merrifield, Recent Progress in Hormone Research 23: 451 (1967): Examples of pnor art methods which allow production and testing of fragments and analogs are discussed below. These, or analogous methods may be used to make and screen fragments and analogs of an isolated alpha4 mtegnn antagonist which can be shown to have biological activity. An exemplary method to test whether fragments and analogs of alpha 4 subunit containing mtegnn antagonists have biological activity is found in Section TV and the Examples. D. Production of Altered DNA and Peptide Sequences: Random Methods Amino acid sequence vanants of a protein can be prepared by random mutagenesis of DNA which encodes the protein or a particular portion thereof. Useful methods include PCR mutagenesis and saturation mutagenesis. A library of random ammo acid sequence vanants can also be generated by the synthesis of a set of degenerate ohgonucleotide sequences. Methods of generating amino acid sequence vanants of a given protein using altered DNA and peptides are well-known in the art The following examples of such methods are not intended to limit the scope of the present invention, but merely serve to illustrate representative techniques Persons having ordinary skill in the art will recognize that other methods are also useful in this regard, such as PCR Mutagenesis, Saturation Mutagenesis and degenerate ohgonucleotide mutagenesis, as descnbed in the below-cited references, and incorporated by reference herein. PCR Mutagenesis: See, for example Leung et al., (1989) Technique 1, 11-15. Saturation Mutagenesis: One method is descnbed generally in Mayers et al., (1989) Science 229, 242 Degenerate Ohgonucleotide Mutagenesis. See for example Harang, S.A., (1983) Tetrahedron 39, 3, Itakura et al., (1984) Ann. Rev Biochem 53, 323 and Itakura et al , Recombinant DNA, Proc. 3rd Cleveland Symposium on Macromolecules, pp 273-289 (A.G. Walton, ed.), Elsevier, Amsterdam, 1981. E. Production of Altered DNA and Peptide Sequences: Directed Methods Non-random, or directed, mutagenesis provides specific sequences or mutations specific portions of a polynucleotide sequence that encodes an isolated polypeptide, to provide vanants which include deletions, insertions, or substitutions of residues of the known amino acid sequence of the isolated polypeptide The mutation sites may be modified individually or in senes, for instance by (1) substituting first with conserved amino acids and then with more radical choices depending on the results achieved; (2) deleting the target residue; or (3) inserting residues of the same or a different class adjacent to the located site, or combinations of options 1-3 Clearly, such site-directed methods are one way in which an N-termmal cysteme (or a functional equivalent) can be introduced into a given polypeptide sequence to provide the attachment site for a hydrophobic moiety. Other well-known methods of site-directed mutagenesis are detailed in the below-cited references, which are mcoφorated by reference herein. Alanme scanning Mutagenesis: See Cunningham and Wells, (1989) Science 244, 1081-1085). Oh onucleoti de-Mediated Mutagenesis: See, for example, Adelman et al., (1983) DNA 2, 183. Cassette Mutagenesis: See Wells et al., (1985) Gene 34, 315 Combmatonal Mutagenesis: See, for example, Ladner et al., W0 88/06630 Phage Display Strategies: See, for example the review by Marks et al., J Biol Chemistry: 267 16007-16010 (1992). F. Other Variants of Alpha 4 Integrin antagonists Vanants can differ from other alpha 4 mtegnn antagonists in amino acid sequence or in ways that do not involve sequence, or both The most prefened polypeptides of the invention have prefened non-sequence modifications that include in vivo or in vitro chemical deπvatization (e.g., of their N-terminal end), as well as possible changes in acetylation, methylation, phosphorylation, amidation, carboxylation, or glycosylation. Other analogs include a protein or its biologically active fragments whose sequences differ from TA2 or those found in U.S. Patents 5,840,299 or U.S. 5,888,507, U.S. 5,932.214 or PCT US/94/00266 by one or more conservative ammo acid substitutions or by one or more non conservative ammo acid substitutions, or by deletions or insertions which do not abolish the isolated protein's biological activity Conservative substitutions typically include the substitution of one ammo acid for another with similar charactenstics such as substitutions withm the following groups vahne, alanme and glycine, leucme and isoleucine. aspartic acid and glutamic acid, asparagme and glutam e; seπne and threonine, lysine and argmme; and phenylalanme and tyrosme The non-polar hydrophobic amino acids include alanine, leucme, isoleucine, valme, prohne, phenylalanme, tryptophan, and methionine The polai neutral amino acids include glycine, senne, threonme, cysteme, tyrosme, asparagme, and glutamine The positively charged (basic) ammo acids include argmine, lysine, and histidine The negatively charged (acidic) ammo acids include aspartic acid and glutamic acid Other conservative substitutions can be readily known by workers of ordinary skill. For example, for the amino acid alanine, a conservative substitution can be taken from any one of D-alamne, glycine, beta-alanme, L-cysteine, and D-cysteine For lysine, a replacement can be any one of D-lysme, argmme, D-arginme, homo- arginme, methionine, D-methionine, ornithme, or D-ornithine Other analogs used withm the invention are those with modifications which increase peptide stability. Such analogs may contain, for example, one or more non- peptide bonds (which replace the peptide bonds) in the peptide sequence. Also included are: analogs that include residues other than naturally occurπng L-amino acids, such as D-ammo acids or non-naturally occurπng or synthetic ammo acids such as beta or gamma amino acids and cyclic analogs Incoφoration of D- instead of L- ammo acids into the isolated hedgehog polypeptide may increase its resistance to proteases. See, U.S. Patent 5,219,990 supra Prefened antibody homologs include an ammo acid sequence at least 60%, 80%, 90%, 95%, 98%. or 99% homologous to an ammo acid sequence of TA2 antibod} of or sequence at least 60%, 80%, 90%, 95%, 98%, or 99% homologous to an ammo acid sequences descnbed in, for instance, U.S. Patent 5,840,299 (e.g, SEQ ID NO 15- hght chain vanable region; SEQ ID NO 17- heavy chain vaπable region), U.S Patent 5,932,214 (e.g., SEQ ID NOS: 2 and 4); and pubhshed patent application W094/16094 (those sequences found in the antι-VLA4 antibody of cell line ATCC CRL 11175) G. Polymer Conjugate Forms Withm the broad scope of the present invention, a single polymer molecule may be employed for conjugation with an alpha4 mtegnn antagonist, although it is also contemplated that more than one polymer molecule can be attached as well Conjugated alpha4 mtegnn antagonist compositions of the invention may find utility in both in vivo as well as non-m vivo applications Additionally, it will be recognized that the conjugating polymer may utilize any other groups, moieties, or other conjugated species, as appropnate to the end use application By way of example, it may be useful in some applications to covalently bond to the polymer a functional moiety imparting UV-degradation resistance, or anti oxidation, or other properties or characten sties to the polymer As a further example, it may be advantageous in some applications to functionahze the polymer to render it reactive and enable it to cross-link to a drug molecule, to enhance vanous properties or charactenstics of the overall conjugated matenal Accordingly, the polymer may contain any functionality, repeating groups, linkages, or other constitutent structures which do not preclude the efficacy of the conjugated alpha4 mtegnn antagonist composition for its intended puφose Other objectives and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims Illustrative polymers that may usefully be employed to achieve these desirable charactenstics are descnbed herein below in exemplary reaction schemes In covalently bonded antagonist/polymer conjugates, the polymer may be functionahzed and then coupled to free ammo acιd(s) of the antagonist to form labile bonds Alpha4 integπn antagonists are conjugated most preferably via a terminal reactive group on the polymer although conjugations can also be branched from nonterminal reactive groups The polymer with the reactive group(s) is designated herein as "activated polymer" The reactive group selectively reacts with free ammo or other reactive groups on the antagonist molecule The activated polymer(s) is reacted so that attachment may occur at any available alpha4 integπn antagonist ammo group such as the alpha amino groups or the epsilon-amino groups of lysmes Free carboxyhc groups, suitably activated carbonyl groups, hydroxyl, guamdyl, oxidized carbohydrate moieties and mercapto groups of the alpha4 mtegnn antagonist (if available) can also be used as attachment sites Although the polymer may be attached anywhere on the alpha4 mtegnn antagonist molecule, a prefened site for polymer coupling to mtegnn antagonists (particularly those that are proteins) is the N-terminus of the alpha4 integπn antagonist Secondary sιte(s) are at or near the C-termmus and through sugar moieties (if any) Thus, the invention contemplates (I) N-terminally coupled polymer conjugates of alpha4 integrin antagonists; (ii) C-terminally coupled polymer conjugates of alpha4 integrin antagonists; (iii) sugar-coupled conjugates; (iv) as well as N-, C- and sugar- coupled polymer conjugates of alpha4 integrin antagonists. Generally from about 1.0 to about 10 moles of activated polymer per mole of antagonist, depending on antagonist concentration, is employed. The final amount is a balance between maximizing the extent of the reaction while minimizing non-specific modifications of the product and, at the same time, defining chemistries that will maintain optimum activity, while at the same time optimizing, if possible, the half-life of the antagonist. Preferably, at least about 50% of the biological activity of the antagonist is retained, and most preferably 100% is retained. The reactions may take place by any suitable art-recognized method used for reacting biologically active materials with inert polymers. Generally the process involves preparing an activated polymer (that may have at least one terminal hydroxyl group) and thereafter reacting the antagonist with the activated polymer to produce the soluble protein suitable for formulation. The above modification reaction can be performed by several methods, which may involve one or more steps. As mentioned above, certain embodiments of the invention utilize the N-terminal end of an alpha4 integrin antagonist as the linkage to the polymer. Suitable conventional methods are available to selectively obtain an N-terminally modified alpha4 integrin antagonist. One method is exemplified by a reductive alkylation method which exploits differential reactivity of different types of primary amino groups (the epsilon amino groups on the lysine versus the amino groups on an N-terminal methionine) available for derivatization on a suitable alpha4 integrin antagonist. Under the appropriate selection conditions, substantially selective derivatization of a suitable alpha4 integrin antagonist at an N-terminus thereof with a carbonyl group containing polymer can be achieved. The reaction is performed at a pH which allows one to take advantage of the pKa differences between the epsilon-amino groups of the lysine residues and that of the alpha-amino group of an N-terminal residue of alpha4 integrin antagonist. This type of chemistry is well known to persons with ordinary skill in the art. A strategy for targeting a polyalkylene glycol polymer such as PEG to the C- terminus of an alpha4 integrin antagonist (e.g., as a protein) would be to chemically attach or genetically engineer a site that can be used to target the polymer moiety. For example, incoφoration of a Cys at a site that is at or near the C-terminus of a protein would allow specific modification using art recognized maleimide, vinylsulfone or haloacetate- activated deπvatives of polyalkylene glycol (e.g., PEG). These denvatives can be used specifically for modification of the engineered cystemes due to the high selectively of these reagents for Cys. Other strategies such as incoφoration of a histidine tag which can be targeted (Fancy et al., (1996) Chem. & Biol 3: 551) or an additional glycosylation site on a protein, represent other alternatives for modifying the C-terminus of an alpha4 mtegnn antagonist Methods for targeting sugars as sites for chemical modification are also well known and therefore it is likely that a polyalkylene glycol polymer can be added directly and specifically to sugars (if any) on an alpha4 integπn antagonist that have been activated through oxidation. For example, a polyethyleneglycol-hydrazide can be generated which forms relatively stable hydrazone linkages by condensation with aldehydes and ketones. This property has been used for modification of proteins through oxidized ohgosacchande linkages. See Andresz, H. et al., (1978), Makromol. Chem. 179: 301. In particular, treatment of PEG-carboxymethyl hydrazide with nitπte produces PEG-carboxymethyl azide which is an electrophihcally active group reactive toward amino groups. This reaction can be used to prepare polyalkylene glycol- modified proteins as well. See, U.S. Patents 4,101,380 and 4,179,337. One can use art recognized thiol linker-mediated chemistry to further facilitate cross-linking of proteins to form multivalent alpha 4 mtegnn antagonist compositions. In particular, one can generate reactive aldehydes on carbohydrate moieties with sodium penodate, forming cystamine conjugates through the aldehydes and inducing cross-linking via the thiol groups on the cystamines. See Pepmsky, B. et al., (1991), J Biol Chem., 266: 18244-18249 and Chen, L.L. et al., (1991) J. Biol. Chem., 266 18237-18243. Therefore, this type of chemistry would also be appropnate for modification with polyalkylene glycol polymers where a linker is incoφorated into the sugar and the polyalkylene glycol polymer is attached to the linker While ammothiol or hydrazme-containmg linkers will allow for addition of a single polymer group, the structure of the linker can be vaπed so that multiple polymers are added and/or that the spatial onentation of the polymer with respect to the alpha4 integπn antagonist is changed. In the practice of the present invention, polyalkylene glycol residues of C1-C4 alkyl polyalkylene glycols, preferably polyethylene glycol (PEG), or poly(oxy)alkylene glycol residues of such glycols are advantageously incoφorated m the polymer systems of interest. Thus, the polymer to which the protein is attached can be a homopolymei of polyethylene glycol (PEG) or is a polyoxyethylated polyol, provided in all cases that the polymer is soluble in water at room temperature Non-hmitmg examples of such polymers include polyalkylene oxide homopolymers such as PEG or polypropylene glycols, polyoxyethylenated glycols, copolymers thereof and block copolymers thereof provided that the water solubility of the block copolymer is maintained. Examples of polyoxyethylated polyols include, for example, polyoxyethylated glycerol, polyoxyethylated sorbitol, polyoxyethylated glucose, or the like. The glycerol backbone of polyoxyethylated glycerol is the same backbone occurπng naturally in, foi example, animals and humans in mono-, di-, and tnglyceπdes Therefore, this branching would not necessaπly be seen as a foreign agent in the body As an alternative to polyalkylene oxides, dextran, polyvmyl pyrrohdones, polyacrylamides, polyvmyl alcohols, carbohydrate-based polymers and the like may be used Those of ordinary skill in the art will recognize that the foregoing list is merely illustrative and that all polymer matenals having the qualities descnbed herein are contemplated. The polymer need not have any particular molecular weight, but it is prefened that the molecular weight be between about 300 and 100,000, more preferably between 10,000 and 40,000. In particular, sizes of 20,000 or more are best at preventing loss of the product due to filtration in the kidneys. Polyalkylene glycol denvatization has a number of advantageous properties in the formulation of polymer-alpha4 mtegnn antagonist conjugates in the practice of the present invention, as associated with the following properties of polyalkylene glycol deπvatives: improvement of aqueous solubility, while at the same time eliciting no antigenic or immunogenic response; high degrees of biocompatibility; absence of in vivo biodegradation of the polyalkylene glycol deπvatives; and ease of excretion bv living organisms. Moreover, in another aspect of the invention, one can utilize an alpha4 mtegnn antagonist covalently bonded to the polymer component in which the nature of the conjugation involves cleavable covalent chemical bonds. This allows for control in terms of the time course over which the polymer may be cleaved from the alpha4 mtegnn antagonist. This covalent bond between the alpha4 mtegnn antagonist and the polymer may be cleaved by chemical or enzymatic reaction. The polymer- alpha4 mtegnn antagonist product retains an acceptable amount of activity. Concunently, portions of polyethylene glycol are present in the conjugating polymer to endow the polymer-alpha4 integπn antagonist conjugate with high aqueous solubility and prolonged blood circulation capability As a result of these improved charactenstics the invention contemplates parenteral, nasal, and oral delivery of both the active polymer-alpha4 mtegnn antagonist species and, following hydrolytic cleavage, bioavailabihty of the alpha4 integπn antagonist per se, in in vivo applications It is to be understood that the reaction schemes descnbed herein are provided for the puφoses of illustration only and are not to be limiting with respect to the reactions and structures which may be utilized in the modification of the alpha4 mtegπn antagonist, e g , to achieve solubility, stabilization, and cell membrane affinity for parenteral and oral administration The activity and stability of the alpha4 integπn antagonist conjugates can be vaned in several ways, by using a polymer of different molecular size Solubilities of the conjugates can be vaned by changing the proportion and size of the polyethylene glycol fragment mcoφorated in the polymer composition III.Therapeutic Applications The amount of active ingredient that may be combined with the earner matenals to produce a single dosage form will vary depending upon the host treated, and the particular mode of administration It should be understood, however, that a specific dosage and treatment regimen for any particular patient will depend upon a vaπety of factors, including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, rate of excretion, drug combination, and the judgment of the treating physician and the seventy of the particular disease being treated The amount of active ingredient may also depend upon the therapeutic or prophylactic agent, if any, with which the ingredient is co- administered The dosage and dose rate of the compounds of this invention effective to prevent, suppress or inhibit cell adhesion will depend on a vanety of factors, such as the nature of the inhibitor, the size of the patient, the goal of the treatment, the nature of the pathology to be treated, the specific pharmaceutical composition used, and the judgment of the treating physician Dosage levels of between about 0 001 and about 100 mg/kg body weight per day, preferably between about 0 1 and about 50 mg/kg body weight per day of the active ingredient compound are useful Most preferably, the VLA-4 binding agent, if an antibody or antibody denvative, will be administered at a dose ranging between about 0 1 mg/kg body weight/day and about 20 mg/kg body weight/day, preferably ranging between about 0 1 mg/kg body weight/day and about 10 mg/kg body weight/day and at intervals of every 1-14 days For non-antibody or small molecule binding agents, the dose range should preferably be between molar equivalent amounts to these amounts of antibody Preferably, an antibody composition is administered in an amount effective to provide a plasma level of antibody of at least 1 mg/ml Optimization of dosages can be determined by administration of the binding agents, followed by assessment of the coating of mtegnn-positive cells by the agent over time after administered at a given dose in vivo The presence of the administered agent ma) be detected in vitro (or ex vivo) the inability or decreased ability of the individual's cells to bind the same agent which has been itself labelled (e g , by a fluorochrome) The prefened dosage should produce detectable coating of the vast majonty of integπn-positive cells Preferably, coating is sustained in the case of an antibody homolog for a 1- 14 day penod Another prefened modality for introducing the antagonist is through combination therapy with a pharmacological agent The pharmacological agent is preferably an agent with some degree of therapeutic efficacy in treating acute bram injury. Such agents may include, but are not limited to, thrombolytic agents such as plasminogen or urok ase, agents that target excitotoxic mechanisms such as Selfotel tm or Aptiganel tm, agents that target mtπc oxide associated neuronal damage such as Lubeluzole tm, agents that target ischemia associated neuronal cellular membrane damage such as Tmhzad tm, agents that target anti -inflammatory mechanisms such as Enhmomab tm The agent may be combined with the alpha 4 mtegπn antagonists of the invention either pnor to. dunng, or after administration of the antagonists IV. Formulations and Methods for Treatment The method of treatment according to this invention involves admimstenng internally or topically to the subject an effective amount of active compound Doses of active compounds in the inventive method are an efficacious, non toxic quantity Persons skilled in the art of using routine clinical testing are able to determine optimum doses for the particular ailment being treated Standard tests for neurological recovery (eg NIH Stroke Scale, Barthel Index, modified Rankin Scale, Glasgow Outcome Scale) will be employed by skilled artisans to determine efficacy The desired dose is administered to a subject one or more times daily, intravenously, orally, rectally, parenterally, mtranasall), topically, or by inhalation The desired dose may also be given by continuous intravenous infusion In parenteral administration of alpha4 mtegnn inhibitors pursuant to this invention, the compounds may be formulated in aqueous injection solution which may contain antioxidants, buffers, bactenostats, etc. Extemporaneous injection solutions may be prepared from steπle pills, granules, or tablets which may contain diluents, dispersing and surface active agents, binders and lubncants which matenals are all well known to the expenenced skilled artisan. In the case of oral administration, fine powders or granules of the compound may be formulated with diluents and dispersing and surface active agents, and may be prepared in water or in a syrup, in capsules or cachets in the dry state or in a non aqueous suspension where a suspending agent may be included The compounds may also be administered in tablet form along with optional binders and lubncants, or in a suspension in water or syrup or an oil or in a water/oil emulsion and may include flavonng, preserving, suspending, thickening and emulsifying agents. The granules oi tablets for oral administration may be coated or other pharmaceutically acceptable agents and formulations may be utilized which are all known to those skilled in the pharmaceutical art. Solid to liquid earners can also be used. Solid earners include starch, lactose, calcuim, sulfate dihydrate, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, and steaπc acid, Liquid earners include syrup, peanut oil, olive oil, saline and water. Ointments and creams are prepared using known polymeπc matenals such as vanous acrylic-based polymers selected to provide desired release charactenstics. Suppositones are prepared from standard bases such as polyethylene glycol and cocoa butter The methods of treatment provided by the present invention relate to methods for treating injuπes to the CNS in a patient, compπsing admmisteπng an alpha4 mtegπn In other embodiments, the methods further include the administration of a pharmacological agent to the patient In prefened embodiments, the pharmacological agent is a thrombolytic agent, a neuroprotective agent, an anti -inflammatory agent, a steroid, a cytokme or a growth factor The thrombolytic agent used m the present invention is preferably tissue plasmmogen activator or urokinase. The neuroprotective agent used in the present invention is preferably an agonist to a receptor selected from the group consisting of N-Methyl-D aspartate receptor (NMDA), α-ammo-3-hydroxy- 5-methyl-4-ιsoxazolepropπonιc acid receptor (AMPA), glycine receptor, calcium channel receptor, bradykmm B2 receptor and sodium channel receptor, or from the group consisting of- the bradykmm Bl receptor, -amino butync acid (GAB A) receptor, and Adenosme Al receptor. Anti-mflammatory agents for use in the present invention include ιnterleukm-1 and tumor necrosis factor family members As contemplated by the present invention, the apha4 integπn antagonist used in the methods of treatment may be an antibody homolog, and preferably a humanized antibody homolog or a fragment of an antibody homolog In other embodiments, the antibody homolg may be linked to a polymer molecule In the methods of the present invention, the alpha4 mtegnn antagonist may alternatively be capable of antagonizing a single alpha4 subunit-contaimng mtegnn, or more than one alpha4 subunit-contaimng mtegnn EXAMPLES Example 1 Protocol for Reversible Middle Cerebral Artery Occlusion in the rat Male Sprague Dawley (SD) or spontaneously hypertensive rats (SHRS) were anesthetized using isoflurane and the nght middle cerebral artery (MCAO) occluded by insertion of a 4-0 nylon monofilament up the internal carotid artery to the oπgm of the middle cerebral artery (MCA) (Zea Longa et al, 1989 Stroke 20:84). After lh the filament was retracted, the ischemic terntory reperfused and the animal allowed to recover. After 24h the rats were sacnficed, at which time brams were removed and analyzed histologically to quantify mfarct volume. Groups of animals were treated with either vehicle (PBS) or the bradykmm B 2 receptor antagonist Hoe 140 (Hoechst) by continuous subcutaneous infusion via osmotic mini-pumps Pπmed mini osmotic pumps (Alza Coφ.,) were implanted into the subcutaneous space at the scruff of the neck immediately pnor to induction of cerebral ischemia. The pumps were loaded to release 300ng/kg/mm Hoe 140 and delivered compound or vehicle at a rate of 8μl/h In a separate expenment groups of animals were treated with either vehicle (stenle isotonic salme), TA2 (mouse anti rat VLA4: Seikagaku Ameπca Inc ) or an isotype control antibody (mouse anti-human LFA3 obtained from Biogen, Inc ) All treatments were administered 24h before surgery intravenously (2.5mg/kg or appropπate volume of vehicle) Example 2: Results of Reversible Middle Cerebral Artery Occlusion Model Vehicle treated control rats that underwent MCAO sustained extensive lesions throughout cortical and subcortical regions of the bram. The ischemic hemisphere was markedly swollen and significant behavioral deficits were observed (eg. hemiparesis resulting in rotation and limb weakness). Spontaneously hypertensive rats sustained more extensive and reproducible brain infarcts than Sprague Dawley rats subjected to the same surgical procedure. Infarct volumes are expressed as mean values +/- s.e.m. Statistical analysis was performed using an unpaired Students' t-test (* denotes p<0.05. ** denotes p<0. 01). Treatment with the bradykinin B 2 receptor antagonist Hoe 140 (n=9) significantly reduced total, cortical and subcortical infarct volume, by 37%, 43% and 17% respectively, compared to vehicle treated controls (n=8) measured 24h after induction of cerebral ischemia in SHRs. In SD rats treatment with the same dose of Hoe 140 (n=6) reduced total, cortical and subcortical infarct volume, by 57%. 93% and 24 respectively, compared to vehicle treated controls (n=7) measured 24h after the induction of cerebral ischemia. These data are consistent with previous findings (Relton et. al, 1997 Stroke 28:1430) and were undertaken as a positive control. In SHRs pre-treatment with the anti α4 antibody, TA-2 (2.5mg/kg iv, n=10), 24h prior to induction of cerebral ischemia significantly reduced total, cortical and subcortical infarct volumes, by 43%, 47% and 33% respectively, compared animals treated with the same dose of an isotype control antibody (n=15) measured 24h after induction of cerebal ischemia. In SD rats using the same protocol, total, cortical and subcortical infarct volume was significantly reduced by 64%, 65% and 38% respectively. The graphs in Figures 1A and IB show the effect of hoe 140 on infarct size 24 hours after 60 minute MCAO in Sprague Dawley and spontaneously hypertensive rats. The figures show inhibition of brain infarction following treatment with hoe 140 (300ng/kg/min) by continuous subcutaneous infusion compared to vehicle treated control animals. Infarct size is reduced in cortical and subcortical regions of the brain in both strains of rats. The graphs shown in Figure 2A and 2B show the effect of anti rat alpha4 antibody (TA-2, 2.5mg/kg) on infarct size 24 hours after 60 minute MCAO in Sprague Dawley and spontaneously hypertensive rats. The figure shows significant inhibition of brain infarction following intravenous pre-treatment with TA-2 antibody compared to animals treated with an isotype control antibody. Protection against brain damage was observed in both strains of rats. These data demonstrate the protective effect of mhibiton of α4 integπns in a model of reversible focal cerebral ischemia in the rat. The pathology of this model is clinically representative of the human condition of stroke and the present data suggest that inhibitors of alpha4 subunit containing integπns may be of significant benefit in the treatment of this and other ischemia-related disorders

Claims: WHAT IS CLAIMED 1 A method to treat central nervous system injury in a patient m need of such treatment , compπsing administration of an α4 mtegnn antagonist 2 The method of claim 1, wherein the step of administration includes further admmistenng a pharmacological agent to the patient 3 The method of claims 1 or 2, wherein the central nervous system injury is stroke, traumatic brain injury or spmal cord injury 4 The method of claim 3, wherein the injury is ischemic or hemorrhagic 5 The method of claim 2 where the agent is a thrombolytic agent 6 The method of claim 5 wherein the thrombolytic agent is selected from the group consisting of tissue plasmmogen activator and urokinase 7 The method of claim 2, wherein the agent is a neuroprotective agent 8 The method of claim 2, wherein the agent is an anti -inflammatory agent 9 The method of claim 2 wherein agent is a stenod 10 The method of claim 2 wherein the agent is a cytokme or growth factor 11 The method of claim 7, wherein the neuroprotective agent is an antagonist of a receptor, the receptor selected from the group consisting of N-Methyl-D aspartate receptor (NMD A), α-ammo-3-hydroxy-5-methyl-4-ιsoxazolepropπonιc acid receptor (AMPA), glycme receptor, calcium channel receptor, bradykmm B2 receptor and sodium channel receptor 12 The method of claim 8, wherein the anti-inflammatory agent is selected from the group consisting of ιnterleukm-1, and tumor necrosis factor family members 13 The method of claim 7, wherein the neuroprotective agent is an agonist of a receptor, the receptor selected from the group consisting of the bradykmm B 1 receptor, α-ammo butync acid (GAB A) receptor, and Adenosme Al receptor 14 The method of claim 4, wherein the injury is ischemic 15 The method of claim 14, where the pharmacological agent is a thrombolytic agent 16 The method of claim 15, wherein the thrombolytic agent is selected from the group consisting of tissue plasmmogen activator and urokinase 17 The method of claim 14, wherein the agent is a neuroprotective agent 18 The method of claim 17, wherein the agent is an antagonist of a receptor, the receptor selected from the group consisting of NMDA receptor, AMPA receptor, glycme receptor, calcium channel receptor, sodium channel receptor, and bradykmm B2 receptor 19 The method of claim 14, wherein the agent is an anti-mflammatory agent 20 The method of claim 19, wherein the anti-inflammatory agent is selected from the group consisting of ιnterleukιn-1, and tumor necrosis factor family 21 The method of claim 17, wherein the neuroprotective agent is an agonist of a receptor, the receptor selected from the group consisting of the bradykmm B 1 receptor, GAB A receptoi, and adenosine Al receptoi 22 A method to treat secondary central nervous system injury resulting from an ischemic msult m a patient in need of such treatment, compπsing administration of an α4 integπn antagonist 23 The method of claim 22. wherein the central nervous system mjur> is selected from stroke, traumatic brain injury, and spinal cord injury 24 The method of claim 22, wherein the stroke is ischemic stroke or hemonhagic stroke 25 The method of claim 22, wherein the secondary brain damage is caused by hemonhagic transformation or cerebral vasospasm. 26 The method of claims 1 or 22, wherein the alpha4 mtegnn antagonist is an antibody homolog. 27. The method of claim 26, wherein the antibody homolog is a humanized antibody homolog. 28. The method of claim 26, wherein the antibody homolog is a fragment of an antibody homolog 29 The method of claim 26, wherein the antibody homolog is linked to a polymei molecule 30 The method of claims 1 or 22, wherein the alpha 4 mtegnn antagonist is capable of antagonizing a single alpha4 subunit-contaimng mtegnn 31 The method of claims 1 or 22, wherein the alpha4 integπn antagomst is capable of antagonizing more than one alpha4 subunit-contaimng tegnn

Inventors: ADAMS STEVE, LOBB ROY, RELTON JANE, WHALLEY ERIC, ADAMS, STEVE, LOBB, ROY, RELTON, JANE, WHALLEY, ERIC
Applicants: ADAMS STEVE, BIOGEN INC, LOBB ROY, RELTON JANE, WHALLEY ERIC, ADAMS, STEVE, BIOGEN, INC., LOBB, ROY, RELTON, JANE, WHALLEY, ERIC
Application year: 2000
Main classification: A61K39
IPC codes: A61K38, A61K39, A61K45, A61P9, A61P17, A61P25, A61P29