NUCLEAR TARGETING BY MEANS OF BACTERIAL PROTEINS

Abstract: A nuclear delivery construct comprises: (i) protein H or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell; and associated therewith (ii) one or more other components whose targeting to the nucleus of the eukaryotic cell is desired.

Description: NUCLEAR TARGETING BY MEANS OF BACTERIAL PROTEINS FIELD OF THE INVENTION The present invention relates to nuclear targeting by means of bacterial oroteins. It is based on the finding that protein P , which can be derived from Streptococcus pyogenes , is targeted to the nuclei of eukaryotic cells, specifically lymphocytes. The present invention therefore relates to nuclear targeting constructs comprising protein H, or a fragment or derivative thereof, associated with another component whose targeting to the nucleus is desired. It also relates to uses of such nuclear targetinα of such constructs, and to pharmaceutical compositions comprising them. BACKGROUND TO THE INVENTION Protein H can be obtained from Streptococcus pyogenes, as described in EP-A-0 371, 199 and WO 91/19740. These publications also provide the amino acid sequence of protein H from Streptococcus pyogenes and the sequence of the DNA encoding it. Protein H has a characteristic spectrum of lmmunoglobulm-binding properties, as described in EP-A-0 371,199 and it is also capable of binding albumin (WO 91/19740) . In WO 91/19740, a number of regions within protein H were identified, and designated S, A, B, Cl, C2, C3 and D regions. Albumin- binding activity was found to be located in the C and/or D regions. SUMMARY OF THE INVENTION We nave now founα that protein H has a further, and unexpected, property. When biotinylated protein H was incubated with T-lymphocytes (Jurkat cells), it was round that protein H was targeted to the cell nucleus. We have also observed the same phenomenon in B-lymphocytes . In the cell, protein H was found to interact with actm, and with nucleopnosmm/B23, a protein known to shuttle between the nucleus and cytoplasm. In the nucleus itself, protein H was found to interact additionally with the nuclear proteins SET and hnRNP A2/B1, resulting m nuclear accumulation of protein H. We believe that protein H penetrates the cell membrane, becomes associated with nucleophosmιn/B23 in the cytoplasm and is transported across the nuclear membrane into the nucleus, where it interacts with SET and hnRNP. As protein H interacts with actm, the actm cytoskeleton may be involved in transporting protem H from the inside of the cell membrane mto the cytoplasm, where it becomes associated with NPM/B23. However, the possibility that protein H simply diffuses through the cytoplasm cannot be excluded. The finding that protein H is targeted to the nucleus was surprising view of the previously known properties of protein H. Previously, protem H has been known as an lmmunoglobulm-b dmg protem, located at the surface of the Streptococcus bacterium, where it protects the bacterium by blocking complement activation at the bacterial cell surface by means of its interaction with the Fc region of IgG. It is therefore surprising that it is also targeted to the cell nucleus, where it may effect a further virulence function on behalf of the Streptococcus bacterium. By contrast, protem A, an lmmunoglobulm-bindmg bacterial cell surface molecule derived from Staphlyococcus a ureus, showed no nuclear accumulation. Proteins A and - are functionally similar in that Doth bmd to tne same site in the Fc region of IgG. The fact that protem H snoweα nuclear accumulation where protem A did not is therefore all the more surprising . Based on our findings, protem ri can be used to target other molecules to the nucleus. For example, protem H can be used to target drugs to the nucleus, or to target nucleic acids to the nucleus for the purpose of gene therapy. We have also found that protem H has a cytostatic effect when targeted to the nucleus. In certain situations, for example where a drug is delivered to a proliferating cancer cell for the purposes of treatmg the cancer, this cytostatic effect will complement the effects of the associated drug. In other situations, it may be desirable to use fragments or derivatives of protein H that do not exhibit the cytostatic effect but are nevertheless capable of being targeted to the nucleus. The invention accordingly provides a nuclear delivery construct comprising: (I) protem H or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell; and associated therewith ii) one or more other components whose targeting to the nucleus of the eukaryotic cell is desired. The invention also provides a pharmaceutical composition comprising sucn a nuclear delivery construct ana a pharmaceutically acceptable carrier. The invention also provides such a nuclear delivery construct for use in a method of treatment of the human or animal body, or for use in a method of diagnosis. The invention also provides use of protem H or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell in the manufacture of a medicament for the treatment of the human or animal boαy in which sucn a construct is targeted to the nucleus of a eukaryotic cell. The mvention also provides use of such a nuclear delivery construct m the manufacture of a medicament for the treatment of disease of the human or animal body in which the construct as defined in claim A is targeted to the nucleus of a eukaryotic cell. The mvention also provides a method of treatmg a disease of the human or animal body by targeting such a construct to the nucleus of a eukaryotic cell, said method comprising administering an effective amount of the construct to the subject. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1. Binding of protem H to the surface of human peripheral blood lymphocytes and the human Jurkat T cell line determined by FACS analysis. Figure 2. Uptake and nuclear accumulation of protein H in Jurkat T cells. Depiction of Jurkat T cells incubated with proteins A or H, cytospmned and stained with FITC-avidin. Protein H (A, B) shows nuclear accumulation, protein A (C) does not. Figure 3. Protein H interacts with nucleophosmin. (A) Results of FPLC on mono-Q column of Jurkat T cells digested with papain and solubilised. (B) Results of radiolabelled pool 85-87 material from (A) being run on protein A-Sepharose (left) and the pooled fractions of the run-through peak from protein A-Sepharose being subjected to a protein H-Sepharose column (right). (C) Identification of NPM in pool 85-87 material from (A) . (D) Comparison of SDS PAGE of in vi tro translated and 35 S-methionine-labelled NPM peptides (left) and SDS-PAGE of the same peptides when applied to protein H-Sepharose. (E) Mapping of the NPM-binding region of protein H by competitive inhibition. Figure 4. Identification of nuclear proteins interacting with protein H. SDS-PAGE gels identifying NPM, protein SET and hnRNP A2/B1. Figure 5. Analysis of the binding of protein H to nucleophosmin and nuclear proteins. (A) Overlay plots of binding of proteins A and H to immobilised NPM (left) or nuclear proteins (right) using plasmon resonance spectroscopy. (B) Competitive inhibition of the binding of 125 I-labelled NPM to protein H-Sepharose with different amounts of unlabeled NPM. Figure 6. Nuclear uptake and cytostatic effect of protein H. (A) SDS-PAGE gels of purified murine B cells incubated with LPS and protein H for 24 hours stained with Coomassie (left) or blotted to a PVDF membrane tright), with the blotted membrane probed with an anti-protein H antiserum, followed by peroxidase-conjugated protein A and developed with ECL. (B) Inhibition of proliferation of murine splenic B cells in response to proteins H and A. Figure 7. Schematic representation of protein H. DETAILED DESCRIPTION OF THE INVENTION Protein H In WO 91/19740, protein H was characterised as having the following domains, from N-terminal to C-terminal: S, A, B, Cl, C2, C3 and D. The S domain is a signal peptide which, in nature, is cleaved from the remaining domains before the mature protein (domains A, B, Cl, C2, C3 and D) is translocated to and inserted into the bacterial cell wall. In the Examples below, a shorter version of protein H is used. This lacks the 41 amino acids of the N-terminal S domain and is also truncated by 30 amino acids at the C- terminus. This version of protein H was produced in E . Coli . It is similar to the version of protein H which, in nature, is released from the cell surface of the Streptococcus bacterium by the action of a cysteine protease. The version released by the protease also lacks the S domain and is also truncated at the C-terminus . It is slightly shorter than the version produced in E. Coli , however . Herein, unless otherwise stated, the term "protein H" means either: (1) protem H incorporating t~e signal peptide, as defined in WO 91/19740 and having S, A, B, Cl, C2, C3 and D αomains and a length of 3^6 ammo aciαs; or (n) mature protem H lacking the S domain and havmg a length of 335 ammo acids; or (in) protein H as produced in E . Coli , lacking the S domain and truncated by 30 ammo acids at the C-termmus, ana having a length of 305 am o acids; or (IV) protein H as cleaved from the Streptococcus cell surface by the cysteme protease, lacking the S domain and truncated at the N-terminus by a number of ammo acids. The precise length of this version of protem H is not yet known, but its molecular mass suggests that the N-termmal truncation is in the order of 50 amino acids, such that it has a length of approximately 285 am o acids. Thus, this version of protein H may, for example have an N-termmal truncation of from 35 to 45, 45 to 50, 50 to 55 or 55 to 65 am o acids, giving it a length, respectively, of 270 to 280, 280 to 285, 285 to 290 or 290 to 300 amino acids. The full 376 ammo acid sequence is given below (see Sequence information section) as SEQ ID No. 6, together with the coding DNA sequence (SEQ ID No. 5) . Am o acid No. 1 represents the beginning of the A domain and tne boundaries of each region and each version of protein H are indicated on the sequence. In other words, ammo acid No. 1 is the first ammo acid of the mature prote (version (ii) of protein H as defined above) . The numbering differs from that used in WO 91/19740 in that, in WO 91/19740, amino acid No. 1 is the first amino acid of the S domain, which is a signal peptide that is absent from the mature protein. Protein H can be obtained by the methods described in EP- A-0 371, 199 and WO 91/19740, and can also be produced using the methods of Akesson et al , 1990; and Frick et al , 1994, in combination with the methods described in the Examples. Any of the above-mentioned versions of protein H can also be synthesised by recombinant means, based on the sequences given herein and using standard techniques known in the art (as exemplified, for example, by Sambrook et al , 1989, Molecular Cloning: A Laboratory Manual) . The same applies to fragments and derivatives of protein H as defined herein. Similarly, protein H and fragments/derivatives thereof can be prepared synthetically by techniques of peptide synthesis already known in the art. This applies especially to fragments of protein H. Nuclear targeting Based on the experimental results presented herein, protein H is capable of being targeted to the nuclei of eukaryotic cells. Targeting has been demonstrated in T- lymphocytes (Jurkat cells) and B-lymphocytes (Bjab cells) . For the purposes of the invention, protein H and its fragments and derivatives are capable of being targeted to the nuclei of eukaryotic cells. A person of skill in the art can determine whether or not any given fragment or derivative is capable of being so targeted in any given cell type using techniques based on those described in the Examples. For example, the fragment or derivative can be biotiny ated, then incubated with the cells in question. The mtracellular distribution of the biot ylateα fragment or derivative can then be determined, for example using FITC-Avidm in conjunction with immunofluorescence microscopy. A person of skill in the art will also be able to devise aαditional methodologies to determine whether or nor protem H or a fragment or derivative thereof is capable of being targeted to the nucleus of any given cell type. Nuclear localisation has been demonstrated n T- lymphocytes (JurKat cells/ and B-lymphocytes (Bjab cells) . Preferaoly, constructs of the invention effect targeting to T-lymphocytes and/or B-lymphocytes. It is not yet clear whether protem H is capable of bemg targeted to the nuclei of all eukaryotic cell types or whether it is selectively targeted to the nuclei of certain cell types, or whether it is targeted to the nuclei of all cell types to some extent but more strongly in certain cell types. However, this can readily be determined by a person of skill in the art as described above . In accordance with the mvention, it is preferred that protein H and its fragments/derivatives are capable of interacting with nucleophosmm/B23. It is also preferred that protem H and its fragments/derivatives are capable of interacting with actm. It is also preferred that protein H and its fragments/derivatives are capable of interacting with the nuclear protem SET. It is also preferred that protem H and its fragments/derivatives are capable of interacting with the nuclear prote hnRNP A2/B1. Optionally, protem H and its fragments/derivatives may be capable of interacting with further cytoplasmic and/or nuclear protems, for example otner hNRNPs, or transcription factors. A person of skill in the art can determme whether or not a given fragment/derivative does interact with any of the above- mentioned protems using techniques based on those of the Examples. Although it is not yet certain whether protem H is capable of being targeted to the nuclei of all eukaryotic cell types or whether it is selectively targeted to the nuclei of some cell types, it is possible to identify some preferred cell types to which protem H and its fragments/derivatives can be used to target associated components in nuclear delivery constructs. Nucleophosmin (NPM) /B23 is known to act to shuttle proteins between the cytoplasm and the nucleus. It is ubiquitously expressed but it is up-regulated in certain cell types. In particular, NPM/B23 is more abundant m tumour and proliferating cells than in resting cells. It is reasonable to predict that proliferating and tumour cells, having a larger available pool of NPM/B23, will be more effective in translocating protem H and its fragments or derivatives mto the nucleus. Thus, according to the mvention, it is preferred to use protein H and its fragments/derivatives to target associated components to cells in which NPM/B23 is up- regulated. Preferred cell types m which protem H and its fragments/derivatives can be used to target associated components to the nucleus mclude tumour cells, virus- infected cells and healthy but proliferating cells that show increased levels of NPM/B23. Preferred virus-infected cells are cells mfected by the human immunodeficiency virus (HIV) , for example CD4" T- cells; or the human Papiiloma virus (HPV), for example cervix epithelial cells and prostate epithelial cells; or a Rhinovirus, for example nasal epithelium cells. Some preferred tumours include rapidly proliferating tumours in general; gliomas and other central nervous system tumours such as neuroblastomas ; leukaemias; lymphomas; lung tumours; sarcomas; colon tumours such as carcinomas, e.g. low-grade colon tumours that have shown invasion (Duke III-IV) ; dispersed renal carcinomas; tubal carcinomas, gastric carcinomas; and prostate carcinomas. Further, constructs of the invention may be used to target therapeutic agents to the nuclei of cells involved inflammatory conditions, as inflammatory conditions commonly involve cell proliferation. Examples of such inflammatory conditions include arthritis, particularly rheumatoid arthritis; arteritis; chondritis; cholitis; dermatitis; enteritis; myositis; tendosynobitis ; and autoimmune inflammatory conditions such as SLE (systemic lupus erythematosis) . Fibroblasts are a further preferred cell type in which nuclear targeting may be achieved by constructs of the invention. The cytostatic effect of protein H As described in the Examples, protein H was found to have a cytostatic effect on murine B-lymphocytes, preventing them from proliferating but not inducing apoptosis (cell death) . It is not yet clear whether protein H has this effect on all eukaryotic cell types. In situations where protein H and its fragments/derivatives are used to deliver other molecules to the nuclei of proliferating cells, especially tumour cells, this cytostatic effect is likely to be beneficial. In particular, in the case of tumour cells, preventmg the cells from proliferating will complement tne activity of the associated component and thus assist in comPattmg the tumour. In other situations, where it is not desirable to prevent proliferation of the cells, it is preferred to use fragments/derivatives of protein H that are capable of being targeted to the nucleus but which do not exhibit the cytostatic effect. A person of skill m the art will be able to identify such fragments and derivatives by preparing fragments/derivatives by means known in the art and then testing them to determme whether or not they (l) retain the ability to be targeted to the nucleus (see "protein H" above) ; and (ii) exhibit the cytostatic effect, which can be done using techniques based on those given in the Examples e.g. by exposing the fragments/derivative to proliferating cells and observing whether or not they continue to proliferate. Fragments and derivatives of protein H For the purposes of the mvention, a derivative of prote H consists essentially of one of the four ammo acid sequences defined herein with respect to SEQ ID No. 6 (see sections entitled "protem H" and "sequence information") . A fragment of protein H is a fragment of any of these four sequences or a fragment of a derivative of any of these four sequences. Such fragments and derivatives are capable of being targeted to the nuclei of eukaryotic cells as described above in the section entitled "nuclear targeting". In particular, a derivative of prote H may be an allelic variant cr species homologue of protein H wnich occurs naturally and is capable of being targeted to the nucleus of a eukaryotic cell in a substantially similar manner to the four versions of Streptococcus pyogenes prote H as defined herein. Such allelic variants and species homologues will typically be derived from other bacteria, for example, other cocci such as species of Staphylococcus or, preferably, Streptococcus . Allelic variants and species homologues can be obtained using techniques mown in the art, based on the use of probes derived from the Streptococcus pyogenes nucleic acid coding sequence as probes. For example, such a probe can be used to probe libraries made from bacterial cells in order to obtain clones encoding the allelic or species variants. The clones can be manipulated by conventional techniques to express a protein which, according to the invention, is a derivative of protein H. Preferably, according to the invention, derivatives of protein H have at least 70%, at least 80%, at least 90%, at least 95%, at least 98% or at least 99% homology with one of the four protein H sequences defined herein with respect to SEQ ID No. 6. More preferably, a derivative will have at least 95%, or at least 99% homology with one of those four sequences over a region of at least 20, preferably at least 30, for instance at least 40, 60 or 100 or more contiguous amino acids. Methods of measuring protein homology are well known in the art and it will be understood by those of skill in the art that in the present context, homology is calculated on the basis of amino acid identity (sometimes referred to as "hard homology") . The sequence of derivatives of the invention may differ from that of one of the four protein H sequences defined herein with respect to SEQ ID No. 6 by one or more amino acid substitutions. For example, 1, 2, 3, 4, 5 to 10, 10 to 20 or 20 to 30 substitutions may be present, as long as the derivative has the ability to be targeted to the nucleus of a eukaryotic cell in a substantially similar way to protein H. Preferably, substitutions are conservative. For example, conservative substitutions may be made according to the following table. Amino acids in the same block in the second column and preferably in the same line in the third column may be substituted for one another in a conservative manner. Similarly, derivatives of the invention may show one or more deletions compared to any of the four protein H sequences defined herein with reference to SEQ ID No. 6. Each deletion may be deletion of, for example, 1, 2, 3, 4 or 5 to 10 amino acids. Similarly, derivatives of the invention may show one or more insertions compared to any one of the four protein H sequences as defined herein with reference to SEQ ID No. 6. Each insertion may comprise, for example, 1, 2, 3, 4 5 to 10 or 10 to 20 amino acids. For example, 1, 2, 3, 4 5 or more such deletions or insertions may be present. According to the invention, fragments of protem H, and of derivatives as defined above, may be of any length and may be derived from any region of protein H or one of its derivatives, as long as they have the capacity to be targeted to the nucleus of a eukaryotic cell. For example, suitable fragments may have a length of from 1 to 20 amino acids, from 20 to 50 amino acids, from 50 to 100 amino acids, from 100 to 150 amino acids, from 150 to 200 amino acids, from 200 to 250 amino acids, from 250 to 300 amino acids, from 300 to 350 amino acids, or greater than 350 amino acids. Preferably, fragments are derived from the more N- terminal regions of protein H. This is because we have found that the A region of protein H, and especially the AB region (i.e. a fragment consisting of the A and B regions) bind to NPM/B23 in a similar manner to complete protein H. We have found that the AB region binds to NPM/B23 more efficiently than complete protein H, and that the A region also binds to protein H, albeit with lower efficiency than complete protein H. The inhibition experiments given in the Examples (see Figure 5C) also suggest that the AB region may be capable of binding to protein SET and hnRNP A2/B1. This suggests that the A region, and preferably the AB region, may be capable of being targeted to the nucleus. Therefore, fragments of the invention preferably comprise the A region, more preferably the AB region. Optionally, other regions of the protein may also be present. The AB region of protein H of Streptococcus pyogenes is amino acids 1 to 117 in SEQ ID No. 6. Preferably, all of these 117 amino acids are present. However, a skilled person will also be aole to investigate smaller fragments of the AB region to determme wnether or not they retain the capacity to be targeted to the nucleus. In particular, recombinant techniques can be used to generate such fragments and techniques based on those given in the Examples can be used to determme whether or not a given fragment is targeted to the nucleus. Therefore, AB fragments may comprise, for example, 1 to 20, 20 to 50, 50 to 80, 80 to 100 or more of the 117 ammo acids of the AB region. In such fragments, the AB region mav be truncateα at its N-termmus by, for example, 1 to 5, 5 to 10, 5 to 20 or 20 to 50 ammo acids and/or at its C-termmus by, for example, 1 to 10, 10 to 20 or 20 to 50 ammo acids. Optionally, derivatives of the invention may comprise protein H or a fragment of protem H as defined herein, and be extended at either the N or the C-termmus or both by an unrelated am o acid sequence. For example, such a sequence may be of up to 10, up to 20, up to 30, up to 50 or up to 100 am o acids m length, or longer (the invention also provides fusion protems comprising protein H or a derivative or fragment thereof: see below) . In the nuclear targeting constructs of the invention, a revealing label may be present, and may be attached either to protem H or the fragment/derivative of protein H, or to one of the other components. The revealing label may be any suitable label which allows the polypeptide to be detected. Suitable labels mclude radioisotopes (e.g. 125 I, 35 S),an enzyme, an antibody, a polynucleotide or a linker such as biotm. In the nuclear targeting constructs of the invention, the protein H component, __ . e . protem H or a iragment or derivative thereof, may be present in a purely peptiαyl form. Alternatively, it may be chemically modified, e.g. post-translationally mod__fιeα. For example, it may oe glycosylated or comprise modified ammo acid residues. Fragments and derivatives of the invention may be synthesised m any suitable manner. Typically, they will be prepared by recombinant means. However, where appropriate, they may also be made synthetically. For example, they may be made using known techniques of peptide synthesis. This applies especially to fragments of protein H. Another consideration is the IgG-bmd g properties of protein H. In general, it is not desirable that fragments/derivatives of protem H retain IgG-bmdmg properties. This is because bmdmg to IgG may lead to the formation of immune complexes which could lead to undesirable side effects and/or reduce protem H' s capacity to exert a cytostatic effect. Thus, where the construct of the invention is to be administered by a route that allows the opportunity to form immune complexes (notably intravenous injection) , it is preferred that the construct comprises a fragment or derivative that has no capacity to bmd to IgG, or at least has a reduced capacity compared to intact prote H. The IgG bmdmg site is around 20 to 30 ammo acids long, and spans the boundary between the A and B regions. Thus, it may be desirable to use a derivative of protein H in which this region is deleted or mutated so that it has no capacity, or a reduced capacity, to bind to IgG. Of course, any such modifications should preferably be made without appreciably disrupting the nuclear targeting effect of the invention. Thus, it is preferred that such derivatives retain the ability to interact with NPM, SET and hnRNPl. It should also be noted that protem H naturally forms dimers. The dimers have a greater capacity to bmd to IgG than isolated protem ri monomers. Formation of dimers is favoured below 3 1 C (i.e. normal human body temperature) but the dimers are less stable above 37°C (See, for example, Nilson et al Biochemistry, 1995, 34, ppl3688-13698 ) . Thus, the IgG bmdmg capacity of protem H in v vo may actually be lower than m vi tro experiments below 37°C suggest. For this reason, even complete prote H does not necessarily have a great enough IgG bmdmg capacity m vivo to disrupt the nuclear targeting effect of the invention. Components which may be targeted to the nucleus when associated with protein H and its fragments/derivatives In principle, the other component of the nuclear delivery construct may be of any nature, as long as its targeting to the nucleus is desired. For example, the other component may be a nucleic acid, i.e. polypeptide, i.e. a DNA or RNA; a polypeptide, i.e. a protem or peptide, for example an antigen or antibody, e.g. an antibody to a nuclear protem; a small molecule drug; a liposome; or a detectable marker. So far as nucleic acids are concerned, the nuclear targeting properties of protem H represent a novel means of carrying out gene therapy by delivering DNA or RNA to the nucleus. Thus, nucleic acids encoding a protein can be delivered to the nucleus, with a view to their being expressed in tne nucleus. For example, the nucleic acid may be contamed withm a nuc eic acid construct that effects integration of the nucleic acid mto the genome of the cell. Alternatively, the nucleic acid may be contained withm a nucleic acid construct that is designed to replicate withm tne cell without integration into the genome of the cell, for example withm a so- called "mmi-cnromosome" . This avoids tne well-known difficulties associated with viral vectors, e.g the risk of uncontrolled viral multiplication . Protem H and its fragments/derivatives can be used to target antisense nucleic acids to the nucleus, with a view to their forming a duplex with RNA produced in the nucleus and suppressing the expression of the protem it encodes. The constructs of the invention may thus be associated directly with antisense RNA, or they may be associated with a construct encodmg an antisense RNA, which is transcribed in the nucleus of the cell. where the targeting constructs of the invention are used to deliver antisense nucleic acids to cancer (tumour) cells, antisense RNA can be used to suppress the expression of proteins involved in the cancer phenotype. For example, antisense RNA may be used to suppress the expression of protems from myc, bcl2 , bclx or cyclin genes . Alternatively, antisense RNA to the RNA transcribed from an HLA-DM gene may be used. Nucleophosmin appears to be a common target in chronic graft-versus-host disease after transplantation. Thus, possible modulation of NPM expression by protem H or derivatives thereof in transplanted organs may be developed as a means of reducing the incidence and severity of graft-versus-host disease . HLA-DM is involved in loading peptides on to MHC class II molecules, which leads to their presentation as antigens to CD4 T cells and, ultimately, to the recognition of foreign peptides by T cells. This phenomenon underlies graft-versus-host disease, as recognition of foreign peptides by T cells is at least partly responsible for the rejection of grafted tissue. In the absence of HLA- DM, only the invariant clip peptide is presented, which does not provoke the host/graft reaction. Therefore, antisense RNA to HLA-DM may be useful in to interrupting the process by which foreign peptides are presented as antigens by MHC class II molecules, preventing their recognition as antigens by T cells and thus preventing the rejection of grafted tissue by the host tissue and promoting its tolerisatiuon. This potentially applies both to allografts (where the grafted tissue come from the same species as the recipient host) and to xenografts (where the grafted tissue comes from another species). So far as small molecule drugs are concerned, one possibility is to use protein H and fragments/derivatives of protein H to deliver cytotoxic agents. Thus, if protein H exhibits selective nuclear targeting to cells having enhanced B23 expression, particularly tumour cells, protein H represents a way of targeting a cytotoxic agent to a tumour cell, with a view to killing the tumour cell. Another possibility is to use protein H and fragments/derivatives of protein H to deliver peptides to the nucleus. Some preferred peptides are those which chelate certain metal ions, for example ions, such as Zn , Mn^ or Mg . Many DNA processing enzymes and transcription tactors require ions and limiting the supply of such ions by chelation could reduce the division of cells to wnicn the peptides are targeted. This is expected to be useful in the treatment of tumours, where chelation of certain ions may prevent the proliferation of the tumour cells. For example, targeting of chelating peptides that chelate a particular ion will selectively mnibit certain DNA processing enzymes and transcription factors. If desired, a cytotoxic effect can also be achieved by increasing the amount of chelating peptide used. Other preferred peptides are those that interact with transcriptional activators or co-activators involved in regulating tumour cell growth or inflammatory responses, the aim being, respectively, to reduce tumour cell growth or to prevent or reduce the inflammatory response. Where protem H or a fragment or derivative thereof is attached to a detectable marker, any suitaole marker which allows the construct to be detected may be used. Suitable markers mclude radioisotopes (e.g. 125 I, 35 S),an enzyme, an antibody, a polynucleotide or a linker such as biotin. In particular, markers that allow detection of the construct by imaging techniques are preferred. Such imaging techniques may be used in diagnostic methods. Thus, if protem H is selectively targeted to the nuclei of certain cell types, it could be used as a marker for those cell types. In particular, if protein H is selectively targeted to the nuclei of certain tumour cells, or certain virally mfected cells, then protein H or fragments/derivatives thereof can be labelled and used as a marker for those cell types. This can be used to diagnose the presence of such cells. Thus, suitably labelled, protem H or fragments/derivatives thereof can be used to diagnose the presence of tumour or virally fected cells to which protem H is selectively targeted. Once such imaging techniques reveal that protem H or a fragment or derivative thereof accumulates in the nuclei of the cells of a given tumour, or type of tumour, a further construct of the invention can also be used to target therapeutic agents to that tumour, or type of tumour. In the nuclear delivery constructs of the invention, there may be one component which is protem H or a fragment or derivative thereof, as defined herein, and one component which is another molecule (i.e. a 1:1 ratio) . Alternatively, the two components may be present with a different ratio, for example 1:2, 1:3, 1:4, 1 : 5 or higher; or 5:1 or greater, 4:1, 3:1, 2:1 or 1:1. Where there is more than one component associated with protem H, these components may be the same or different. Similarly, there may be more than one molecule of protein H and more than one molecule of the other component, e.g a ratio of 2:2, 3:3, 2:3 or 3:2. Association between protein H and its fragments/derivatives and the other component (s) of the nuclear delivery construct The other component (s) may be associated with protem H any manner, as long as the association is strong enough for protem H to transport the other component (s) into the nucleus. The other component (s) may therefore be associated with protem H by any means known in the art. For example, the association may be covalent associated. Alternatively, the association may oe non-covaient . For example, the other component (s) may be conjugated to protein H or a fragment or derivative of protem H. Where the other component (s) is/are covalently attached, tnis attachment may be at either the C-termmus or the N- termmus, or anywhere between the two termini. In constructs where the other component is a polypeptide, it may be attached by a peptide bond. Where protem H or a fragment/derivative s non- covalently associated with the other component (s) , the association may be, for example, by means of hydrophobic interactions, hydrogen bonding or electrostatic interactions . Where the other component is peptidyl in nature; e.g. a protein, polypeptide or peptide, it may be desirable to produce the construct as a fusion protem between protem H and the second protem. Thus, a composite DNA sequence encoding protem H or a fragment/derivative and the other peptidyl component can be prepared by techniques known in the art and a fusion protem can be expressed recombinantly from this composite sequence. Optionally, a linker nucleic acid sequence may be provided between the two coding sequences, such that a linker region is present in the expressed fusion protein. Alternatively, the coding sequences of protem H or a fragment/derivative of protem H may be joined directly together m-frame. Fusion protems are discussed in more detail below. Fusion proteins In a fusion protein of the invention, protein H and the other peptidyl component may oe present in either orientation, i.e. protem H or a fragment or derivative thereof may be C-termmal or N-termmal to the other peptidyl component. A linker peptide may be present between the two components. Typically, the linker will be flexible, allowing movement of the protem H component with respect to the other peptidyl component. Preferably, the linker will not inhibit the correct expression or folding of either of the two components. Preferably, the linker will not be toxic or immunogenic. Typically, the peptide linker comprises ammo acids that do not have bulky side groups and therefore do not obstruct the folding of the protein component. Further, it is preferred to use uncharged amino acids in the linker. Preferred amino acids for use in linkers include glycine, serine, alanme and threonme. The peptide linker may be of any suitable length which allows correct folding of the two components. The linker may be from one to four ammo acids in length. Alternatively, the linker may be from 5 to 50 amino acids in length, for example 10 to 30 amino acids or 15 to 25 amino acids in length. Preferably the linker consists essentially of one or more glycine residues and one or more serine residues. Such a linker is termed herein a glycine-serine linker. The linker may contain from 1 to 50, typically 5 to 30 or 10 to 20 glycine residues. The linker may contain from 1 to 50, typically 5 to 30, or from 10 to 20 serine residues. The linker may consist only of glycine and serine residues. One possible type of glycine-serine linker may compπse the sequence (Gly-Gly-Gly-Gly-Ser ) p . n may oe any integer from 2 to 10, preferably from 2 to 5, more preferably 3 or Δ r most preferably 3. Other comomations of glycine and serine can also be suitable linkers. The invention also proviαes nucleic acid sequences, i.e. DNA and RNA sequences, encodmg the fusion protems of the invention. The invention also provides: vectors comprising these nucleic acid sequences; cells containing such vectors or nucleic acid sequences; and methods of producmg fusion protems of the invention, comprising expressmg the nucleic acid sequence encodmg the fusion protem in a cell, and recovering tne fusion protem thus obtained. A person of skill in the art will be able to generate nucleic acid sequences encodmg fusion protems by techniques known in the art, and will also be able to generate vectors comprising those sequences and transform or transfect cells with such vectors in order to achieve expression of the fusion protem. Typically, in a vector, the nucleic acid sequence encoding the fusion protem will be operably linked to a control sequence capable of providing for the expression of the fusion protem in the host cell. The term "operably linked" refers to a juxtaposition wherem the coding DNA sequence and the control sequence are in a relationship which permits expression of the coding sequence under the control of the control sequence. Typically, the control sequence will be a promoter. Optionally, other components may be present in the vector, for example, any of the following: an origin of replication; an enhancer; a selectable marker gene, typically under the control of a promoter; a terminator sequence; or a polyadenylation sequence. Any such components will oe positioneα such that they are operably linked to the sequence encoding the fusion protem, i.e. in a position such that they exert the desireα effect on the coding sequence. Medical applications of the invention Nuclear delivery constructs of the invention can be used to deliver components as described above, in association witn protem H or a fragment/derivative thereof, to the nucleus. This will be useful combatting a number of diseases of the human or animal body. In particular, as NPM/B23 is up-regulated in tumour and proliferating cells, nuclear delivery constructs of the mvention will be useful in combatting diseases of proliferating cells, or diseases that involve uncontrolled cell proliferation. In particular, nuclear delivery constructs of the invention can be used to deliver components to tumour cells, thereby combatting the tumour. In this connection, it is desirable to use nuclear delivery constructs of the invention in which the component associated with protem H or a fragment/derivative thereof is a tumour-suppressive drug or cytotoxic drug. As indicated above, the cytostatic effect of protem H may complement the effect of these drugs . Some preferred tumours for such delivery mclude rapidly proliferating tumours m general; gliomas and other central nervous system tumours such as neuroblastomas ; leuKaemias; lymphomas; lung tumours; sarcomas; colon tumours such as carcinomas, e.g. low-grade colon tumours that have shown invasion (Duke III-IV) ; dispersed renal carcinomas; tubal carcinomas, gastric carcinomas; and prostate carcinomas. Similarly, nuclear delivery constructs of the mvention can be used to target drugs to virus-infected cells, thus combatting the viral infection. Preferred virus-mfected cells are cells infected by the human immunodeficiency virus (HIV) , for example CD4 + T-cells; or the human Papilloma virus (HPV) , for example cervix epitnelial cel±s and prostate epithelial cells; or a Rhmovirus, for example nasal epithelium cells. Thus, where a nuclear delivery construct of the invention comprises protem H or a fragment or derivative thereof in association with appropriate antiviral agent, the construct can combat infection by one of these viruses. Further, as inflammatory conditions often involve cell proliferation, constructs of the invention may be used to target therapeutic agents to the nuclei of cells involved inflammatory conditions, thus treatmg these conditions Examples of such inflammatory conditions include arthritis, particularly rheumatoid arthritis; arteritis; chondritis; cholitis; dermatitis; enteritis; myositis; tendosynobitis; and autoimmune inflammatory conditions such as SLE ■ systemic lupus erythematosis) . Also, where the nuclear delivery construct comprises DNA or RNA, gene therapy can be effected. Any suitable gene may be delivered to the nucleus in this way. Where the targeting constructs of the invention are used to deliver antisense nucleic acids to cancer (tumour) cells, antisense RNA can be used to suppress the expression of proteins involved in the cancer phenotype . For example, antisense RNA may be used to suppress the expression of proteins from myc, bcl2, bclx or cyclin genes, thus combatting the cancer concerned. Alternatively, as described above, antisense RNA to the RNA transcribed from an HLA-DM gene may be used, with a view to combatting graft-versus-host disease. The use of nuclear targeting constructs of the invention in the treatment of a condition may be combined with other treatments. In particular, where treatment of a tumour is desired, it may be combined with or used in association with other chemotherapeutic or chemopreventive agents for providing therapy against tumours. Similarly, it may be combined with the use of other agents for treatment of viral infections or other conditions . Nuclear targeting constructs of the invention may be also be used in diagnostic methods. For example, as described above, protein H or a fragment or derivative thereof may be associated with a detectable marker, especially an imaging agent. Pharmaceutical compositions The present invention also provides pharmaceutical compositions comprising a nuclear delivery construct according to the invention and a pharmaceutically acceptable carrier. Any suitable pharmaceutical formulation may be used. For example, suitable formulations may include aqueous or non-aqueous sterile injection solutions, which may contain anti-oxidants , buffers, bacteriostats, bactericidal antibiotics and solutes which renαer the formulation isotonic with the oodily fluids of the intended recipient; and aqueous and non-aqueous sterile suspensions which may mclude suspending agent and thickening agents. Some preferred formulation ingredients mclude mannitol or another sugar and/or phospnate- buffered sal e (PBS) . It should be understood that addition to the ingredients particularly mentioned above, the formulations of this mvention may mclude otner agents conventional in the art havmg regard to the type of formulation n question. Dosage information According to the invention, any effective, non-toxic amount of a nuclear deliver construct of the mvention may be administered to a patient. The dose of the nuclear delivery construct may be adjusted according to various parameters, for example the nature of the component which is being delivered to the nucleus, the age, weight and condition of the patient to be treated, the mode of administration used, the condition to be treated, the efficiency of the particular nuclear delivery construct being used in transporting the associated component to the nucleus and the required clinical regimen. As a guide, it appears that 10 6 B-lymphocytes accumulate in the region of lng to lOng of protein H in their nuclei . This suggests that the amount of nuclear delivery construct administered may be such that the dose comprises 10 " g to 10 ~u g of prote H or a fragment or derivative thereof per cell to whicn tne construct is to be delivered, for example lO ' -'g to 10 "d g, e.g. in the region of 10 ~ -'g, 10 ~lj g, 10 _1 -g, 10 -i* g, 10 ~10 g, 10 _a g or lO ' -g per cell. The amount of protein H or a fragment/ derivative thereof thus depenαs on what cells it is desired to deliver the construct to, and how many of them there are. The total amount of the construct delivered also depends on the size of the component (s) associated with protem H or the fragment/derivative. For example, a typical dose of a nuclear delivery construct of the invention might contain 1 to lOOOμg of protein H or a fragment/derivative thereof, for example 1 to 10μg, 10 to lOOμg or 100 to lOOOμg. These dosages are intended only as a guide since a skilled medical practitioner will be able to determme readily the most appropriate dosage for any particular patient and condition. Similarly, the skilled medical practitioner will be able to determine the appropriate dosage schedule, which will vary according to the factors given above in respect of dosage amounts. However, single doses and multiple doses spread over periods of days, weeks or months are envisaged. Routes of administration Nuclear delivery constructs of the mvention can be formulated for clinical administration by mixing them with a pharmaceutically acceptable carrier or diluent, as described above. For example, they can be formulated for topical, parenteral, intravenous, intramuscular or transdermal aαm istration . Of course, the route of administration will be tailored to the particular condition to be treated. For example, where complete protem H, or a fragment/derivative comprising the IgG binding site is used in the construct, it may not be desirable to inject the prote or fragment/derivative intravenously, as this may lead to the formulation of immune complexes with IgG. In these situations, other means of administration are preferred, e.g. αirect delivery of the construct to the site where it is needed. For example, in the case of a tumour, it is desirable to inject the protem or fragment/derivative directly into the tumour. However, as noted above, even the IgG bmdmg capacity of complete protein H is not necessarily enough to disrupt the nuclear targeting effect of the invention. EXAMPLE The following Example illustrates the invention. Summary Some strains of the human pathogen Streptococcus pyogenes express a surface protem called protem H, which is released from the streptococcal surface by a cysteine prote nase produced by the bacteria. Here we find that soluble protem H binds to the surface of lymphocytes and granulocytes. The molecule is taken up by lymphocytes and transported to the nucleus through a previously unknown mtracellular pathway. In the cytoplasm, protem H was found to bind to actm whereas when protems were solubilised from membrane fractions by papam, protem H was found to interact with nucleophosmιn/B23, a prote known to shuttle oetween the nucleus ana the cytoplasm. In the nucleus, prote H is dissociated from nucleophosmm/B23 and instead forms complexes with the nuclear proteins SET and hnRNP A2/B1, resulting in nuclear accumulation of protem H and a cytostatic effect . Experimental procedures Bacterial strain, proteins, bacterial expression, in vitro translation, labelling of proteins, coupling of proteins to Sepharose The group A streptococcal stram API of serotype Ml (Akesson et al., 1994) was used. Recombinant prote H and peptide fragments corresponding to the AB and A regions of protem H have been described (Akesson et al., 1990; Frick et al., 1994). For the generation of m vi tro translated NPM, RNA was prepared from Jurkat T cells using RNazol B (Tel-Test Inc., Fπendswood, USA) accordmg to the manufacturer's recommendations. cDNA synthesis was performed by incubation of 5 μg RNA with lx RT buffer (Gibco BRL), 1 mM dNTP, 10 mM DTT, 0.1 mg BSA/ml, 4.5 μM poly dT , 20 U RNase inhibitor (Boehringer Mannheim) and 200 U M-MLV reverse transcnptase (Gibco BRL) in a final volume of 50 μl for 37°C for 1 hour. NPM was PCR amplified using the 5' primer containing a Narl 5 ' -GCAGGGCGCCATGGAAGATTCGATGGACAT-3 ' (SEQ ID No. 1) and the 3 ' reverse primer 5 ' -CAGGAATTCTTATTAAAGAGACTTCCTCCACTGCC-3 ' (SEQ ID No. 2) containing an EcoRI site. For the generation of NPM peptide fragments by in vi tro translation two additional oligonucleotides were used for PCR amplification: The NH2-terminal peptide was generated with the reverse primer 5'-CAGGAATTCTTATTAGCTACCACCTCCAGGG-3' (SEQ ID No. 3) and the primer 5'-TTGATGAAGGTTCCACAGAAAAAAGTAAAACTTGCTG-3' (SEQ ID No.4), was used for the COOH-terminal peptide. The PCR products were blunted and cut with EcoRI, whereas the vector pGem-3Z was cut with HincII/EcoRI , and both were ligated. In vi tro translation was done using TNT Coupled Reticulocyte Lysate Systems (SDS, Falkenberg, Sweden) according to the manufacturer's recommendations. Recombinant protein A was purchased from Pharmacia Biotech, Uppsala, Sweden, and actin from porcine heart was from Sigma (MO, USA) . Protein H was labelled with L I using the Bolton and Hunter reagent (Amersham, UK) . Protein fractions 85-87 purified with FPLC were concentrated in an Amicon centricon concentrator (Amicon, 1 2 5 Inc., Beverly, MA), and labelled with I using the chloramine T method (Greenwood et al., 1963). I was from Nordion Int. Co. (Canada) . Protein H was dialyzed against 0.1 M NaHCO, pH 8.3 + 0.5 M NaCl, and coupled to CNBr-activated Sepharose 4B (Pharmacia Biotech) as previously described (Frick et al., 1995). Electrophoresis and Western blot analysis SDS-PAGE was performed as described by Laemmli (1970) , using a total polyacrylamide concentration of 10% or 13.6 % and 3.3% crosslinking. Samples were boiled for 3 minutes in a buffer containing 2% SDS and 5% 2- mercaptoethanol . Gels were fixed with a mixture of 7% acetic acid and 10% ethanol, dried and autoradiographed. Molecular weight markers were from Sigma. Gels were stained with Coomassie Blue. Protein fractions were applied to PVDF mempranes (Immobilon, Millipore, Bedford, MA, USA) using a Milliblot-D system (Millipore) . Memoranes were blocked at room temperature for 1 hour in VBS (lOmM veronal, 0.15 M NaCl pH 7.4) containing 0.25% Tween-20 and 0.25% gelatin. After incubation at room temperature for 3 h with radiolabelled protem in VBS containing 0.1% gelatin, the membranes were washed four times with 1.0 M NaCl, 10 mM EDTA, pH 7.7, 0.25% Tween-20 and 0.25% gelatin. The filters were air-dried and autoradiographed at -70"C using Kodak X-Omat AR films and Kodak X-Omat regular intensifying screens. Cells and preparation of proteins from membrane fractions from the Jurkat cell line For flow cytometric analysis human peripheral blood lymphocytes (PBL) from healthy volunteers were depleted from erythrocytes and prepared by Ficoll separation (Pharmacia Biotech) . Jurkat cells, a human T cell line, were cultured in RPMI 1640 supplemented with 7.5% FCS and 20mM sodium pyruvate. Membrane preparations were performed in the cold (0-4°C) . 10 ' Jurkat cells were homogenized in homogenization buffer (0.05 M Tris-HCl pH 7.5, 0.25 M sucrose, 0.005 M MgCl2, 0.025 M KC1) followed by centrifugation at 1000 x g for 10 mm. The supernatant was further centrifuged at 105000 x g for 45 min. This supernatant was saved and used as a cytoplasmic fraction whereas the pellet obtained was solubilised in 4 ml 0.01 M Tris-HCl pH 8.0. The protein content was determined with the Coomassie protem assay reagent (Pierce, Boule Diagnostics AB, Huddinge, Sweden). After addition of 0.2 mg papam (Sigma) per mg protein solution, and L-cysteine (Sigma) to a final concentration of 4 mM, the mixture was incubated at 37°C for 45 minutes. To terminate the reaction, 4 ml ice-cold 0.01 M Tris-HCl pH 8.0 and lodacetamide (Sigma) to a final concentration of 6 mM were added, followed oy centrifugation for 1 hour at 105000 x g. Papam was removed from the supernatant by chromatography on DEAE Sephadex A-50 (Pharmacia Biotech) equilibrated with 20 mM Tris-HCl, pH 8.0. The column was washed with 5 volumes 20 mM Tris-HCl pH 8.0, and the material was eluted with 3 volumes of a 0.5 M NaCl in this buffer followed by dialysis against 20 mM Tris-HCl pH 8.0. For fractionation of the papam digested membrane proteins, the solution was loaded onto an ion-exchange column (Mono-Q, Pharmacia Biotech) mounted on a fluid pressure liquid chromatograph (FPLC, Pharmacia Biotech). Elution was performed with a 70 ml linear salt gradient (from 0 to 1 M NaCl in 20 mM Tris-HCl pH 8.0). Fractions of 0.5 ml were collected. Murine splenic B cells from Balb/c mice were isolated as previously described (Axcrona et al., 1995). Lymphocytes at 3x10 /ml were plated out in 96 well plates. B cells were activated with LPS (25μg/ml, Difco) and incubated with protems H and A at indicated concentrations. One μCi [3H] thymidine was added per well for the last 4 hours of a 40 hour culture period, cells were harvested and processed for scintillation counting. Values are mean +/- SD of duplicates. For preparation of nuclear and cytoplasmic extracts from murine B cells, cells were activated for 24 hours at 3.8xl0 6 cells/ml with LPS (25μg/ml) and protein H at lOOμg/ml. Preparation of nuclear extracts from Jurkat T cells and murine B cells Nuclei from Jurkat cells were isolated as described by (Mirkovitch et al., 1984). Preparations of nuclei were resuspended 100 μl of buffer A (50 mM Hepes buffer, 50 mM KC1, 0.1 mM EDTA, 1 mM PMSF, 1 mM DTT, 10% glycerol) and additional buffer A was added to a final volume of 162 μl. 13 μl of 4 M (NH ; ) 2 SO, was added to bring the final concentration to 0.3 M. The cells were rocked for 30 minutes and the viscous material was transferred to a 0.2 ml TLA-100 tube (Beckmann) , followed by centrifugation at 10 5 r P m for 10 minutes. 125 μl of the supernatant was transferred to a second TLA-100 tube, 75 μl of 4 M (NH 2 S0 was added to increase the final concentration to 1.5 M. The solution was centrifuged at 50000 rpm for 5 minutes. The supernatant was removed and the pellet was resuspended in 100 μl of buffer A. Extracts were used immediately or stored at -80°C. Affinity chromatography, competitive binding assay, and plasmon resonance spectroscopy The I-labelled pooled fractions 85-87 from Mono-Q and in vi tro translated NPM peptides were applied onto a Protein A-Sepharose column (Pharmacia Biotech) and the flowthrough fractions were run on a protein H-Sepharose column. The column was extensively rinsed with PBSAT (PBSA + 0.05% Tween-20) . Bound proteins were eluted with 3 M KSCN and the radioactivity of the fractions was measured in a gamma counter. Fractions were also analysed by SDS-PAGE. Competitive binding assays were performed as reported (Akerstrόm and Bjδrck, 1989) . Binding kinetics were determined by surface plasmon resonance spectroscopy using a BIACORE X system (Biacore AB, Uppsala, Sweden) . Actin and nuclear extracts purified on protein H- Sepharose were immobilized on research grade CM5 sensor chips in 10 mM sodium acetate at pH 4.0 and 4.5, respectively, using the amine coupling kit supplied by the manufacturer, whereas biotinylated NPM was coupled to CM5 sensor chips precoupled with avidin (Biacore) . All measurements were carried out in PBST. Analyses were performed at 25°C and at a flow rate of 10 μl/mm. To calculate dissociation and affinity constants, 35 μl of protein H or protems A, H or actm were applied in serial dilutions (2n; starting at 600 μg/ml) . Surfaces were regenerated with 35 μl 1 M KSCN at a flow rate of 10 μl/mm. The kinetic data were analysed by the BIAevaluation 2.2 program (Biacore). Ammo acid sequence analysis Protems were separated by SDS-PAGE and stained with Coomassie Blue. Protem bands were excised and digested m-matrix usmg trypsm. Peptide fragments were separated by reverse-phase HPLC (Vydac 218TP, I.D. 1.6 x 250 mm) and aliquots were analysed by automated Edman degradation using a model 477A sequenator connected to a model 120A on-line PTH-analyser (Applied B osystems, Weiterstadt, Germany) and by mass analysis using cyano-4- hydroxycmnamic acid as a matrix on a Voyager-DE MALDI- TOF mass spectrometer (Perseptive Biosystems, Wiesbaden, Germany) (Herrmann et al., 1996; Herwald et al., 1996). The Blast network server at the National Center for Biotechnology Information (Altschul et al., 1990) was used for sequence homology searching. Antibodies , flow cytometrical and fluorescence microscopical analysis For flow cytometric analysis of human PEL, mouse anti- human CD3, CD4, HLA-DP/DQ/DR (Becton Dickinson, San Jose, CA, USA) and CD8 antibodies (Dako Patts, Gentofte, Denmark) were used. As a positive and negative control for Jurkat T cells, an isotype control set of a γl-FITC, γ2-PE and antι-CD45 PerCP (Becton Dickinson) labelled antibodies were used, where the γl/γ2 antibodies were unspecific fluorochrome-conjugated antibodies. Protems h and A were biotinylated as previously describeα (Axcrona et al., 1995), and used in conjunction with FITC-coupled avidin (Sigma) . Mouse anti-human HLA-DP/DQ/DR antibodies were detecteα with goat anti-mouse FITC-coupled antibody (Becton Dickinson) . FACS-analysis was performed on a Becton Dickinson FACSort flow cytometer (Becton Dickinson) . Each dot blot and histogram represents the analysis of 10 gated cells. For fluorescence microscopy 0.5 x 10" Jurkat cells were incubated with 20μg biotinylated proteins in culture medium for 30 minutes on ice a flat bottomeα 96 well plate. Cells were washed once, followed by continued incubation in a culture chamber at 37°C for the indicated times. The cells were washed twice in 4 ml PBS, taken up in 400 μl PBS, centrifuged on slides m a cytocentrifuge (Shandon, Cytospm 2) at 550 RPM for 3 minutes. After incubation with FITC-coupled Avidm (Sigma) , the cells were examined in a fluorescence microscope (Leica Aristoplan) and photographed. Experimental procedures using anti-protein H or anti-NPM antibodies Preparation of anti-protein H F(ab') 2 fragments Anti-prote H antiserum was applied to a protein G- Sepharose column. The column was extensively washed with PBS and bound IgG was eluted with 0.1 M glycin-HCl pH 2.0. Eluted IgG was dialyzed against acetate buffer pH 4.5 (70 mM CH 3 COONa - 50 mM HCI) followed by proteolytic cleavage with pepsin (ratio of protem: pepsin was 100:1) for 21 hours at 37 °C. The reaction was terminated by raising the pH of the solution to 7.5 with 1 M Tris and uncleaved IgG was removed by subjecting the material to affinity chromatography using protein G-Sepharose. Unbound material corresponding to polyclonal anti-protein H F(ab') 2 fragments was collected and dialyzed against PBS. Coupling of F(ab') 2 fragments to Sepharose 4B (Pharmacia Biotech) was performed as recommended by the manufacturer . Cloning and expression of nucleophosmin (NPM) For expression in E . coli NPM was PCR amplified using the 5' primer containing an EcoRI site 5'- GCAGGAATTCATGGAAGATTCGATGGACAT-3' (SEQ ID No 7) and the 3' reverse primer 5 ' -ATAGCGGCCGCTTATTAAAGAGACTTCCTC-3 ' (SEQ ID No 8) containing a NotI site. The DNA was cloned into the prokaryotic expression vector pGEX-6p-l (Pharmacia Biotech) using the EcoRI and NotI sites. Recombinant NPM fused to Glutathione S-transferase (GST) was expressed and purified according to the manufacturers instructions. After purification on Glutathione Sepharose, the GST tag was cleaved off using PreScission 3 Protease (Pharmacia Biotech) . From 1 1 of an over night culture, approximately 1 mg pure NPM was achieved. Antibodies against NPM were raised in rabbits. Preparation of cytoplasmic and nuclear extracts from Jurkat T cells and Detroit cells Jurkat T cells and Detroit 562 human (carcinoma) pharynx epithelial cells (ATCC CCL 138), incubated with various proteins, were washed five times with PBS, resuspended in buffer A (10 mM Hepes, 15 mM KC1, 2 mM MgCl 2 , 1 mM DTT, 0.1 mM EDTA, ImM PMSF, 1 μg antipain/ml , 0.5 μg leupeptin/ml) and the cell membranes were lysed using 0.2% NP-40. The cytoplasmic fractions were collected after centrifugation at 1000 x g for 10 min and the nuclear pellets were wasned twice with PBS and resuspended in 100 μl of buffer B (50 mM Hepes buffer, 50 mM KC1, 0.1 mM EDTA, i mM PMSF, 1 mM DTT, 10% glycerol). Additional buffer B was added to a final volume of 162 μl and 13 μl of 4 M (NH ) 2 SOa was added to bring the final concentration to 0.3 M. The resuspended nucle were rocked for 30 mm at 4°C and the viscous material was transferred to a 0.2 mi TLA-100 tube (Beckmann), followed by centrifugation at 350 000 x g for 10 mm. The supernatants corresponding to the nuclear fractions were collected and both cytoplasmic and nuclear fractions were subjected to lmmunoprecipitation . lmmunoprecipitation Extracts prepared from Jurkat cells, incubated with protem H or protem L (150 μg) for 16 hours at 37°C, were immunoprecipitated by using polyclonal antibodies against protem H or protem L, 2 μl respectively, for 2 hours at 4°C. 40 μl protem A-Sepharose was added and incubation was continued for 16 hours at 4°C. Extracts from Detroit 562 cells, incubated with protem H were immunoprecipitated similarly. Alternatively extracts from Jurkat cells, incubated with protein H (150 μg) for various timepomts at 37°C, were precleared with 50 μl glycme-Sepharose, for 2 hours at 4°C, followed by lmmunoprecipitation using polyclonal anti-protem H F (ab ' ) 2 -Sepharose (100 μl) for 16 hours at 4°C. The Sepharose pellets were then washed three times with PBS, boiled for 3 mm buffer containing 2% SDS and 5% 2-mercaptoethanol followed by centrifugation at 8000 x g for 5 mm. Supernatants were recovered and subjected to SDS-PAGE and Western blot analysis. Membranes were blocked at 37°C in PBST (PBS + 0.05% Tween-20) containing 5% skim milk and probed with polyclonal antibodies followed by peroxidase-conjugated protein A and developed with ECL. Results Protein H interacts with human lymphocytes and granulocytes Protein H is released from the streptococcal surface through the action of a cysteine proteinase produced by the bacteria (Berge and Bjδrck, 1995) . The E . coli- produced fragment of protein H used in this study is similar in size to the fragment released by the streptococcal enzyme, and in the following Examples protein H refers to this COOH-terminally truncated fragment expressed by and purified from E . coli . The interaction of protein H with the surface of T cells and granulocytes was analysed with flow cytometry. Human peripheral blood lymphocytes were incubated with protein H and the majority (>90%) of the CD3 + , CD4 + and CD8 + cells bound protein H (Figure 1A) . When the binding of protein H to cells within the granulocyte gate was analysed, protein H also stained these cells brightly (Figure 1A) . Protein H binds to IgGFc (Frick et al., 1994) and previous work has indicated affinity also for human MHCII antigens (Akesson et al., 1994). The human Jurkat T cell line was therefore chosen for the subsequent experiments as MHC II expression on these cells could be excluded with flow cytometry. More than 97% of the Jurkat T cells were found to be protein H + as compared to the FITC avidin background. Furthermore, as shown in Figure IB, Jurkat cells were stained by anti-CD45 but not with unspecific γl FITC/γ2 PE mouse mAbs . Protein H is taken up by lymphocytes and accumulated in the nucleus Biotinylated protein H was incubated with Jurkat cells for different timepoints. Following incubation, cells were cytospinned, fixed, and FITC-coupled avidin was added. As demonstrated by immunofluorescence microscopy (Figure 2) protein H was gradually accumulated in the nuclei, and after 8 hours 80% of the nuclei showed staining. In contrast, cytoplasmic staining but no labelling of nuclei was detected when the Jurkat cells were incubated with biotinylated protein A (Figure 2C) . Like protein H, protein A of Staphylococcus a ureus is an IgGFc-binding bacterial surface molecule. Previous work has demonstrated that protein H binds to murine and human B cells (Axcrona et al., 1995) and as in the case of Jurkat cells, protein H was targeted to the nuclei of the human B cell line Bjab, whereas protein A showed no nuclear accumulation. Protein H are taken up by lmphocytes and epithelial cells Further studies were carried out using anti protein H antibodies. 5 x 10 6 Jurkat cells were separately incubated with 150 μg of protein H or protein L for 16 hours. Cytoplasmic and nuclear extracts were prepared and immunoprecipitation was performed using polyclonal antibodies against proteins H and L, respectively, followed by the addition of protein A-Sepharose. Precipitated materials were run on SDS-PAGE and blotted to PVDF membranes. The membranes were probed with polyclonal antibodies against proteins H and L, respectively, followed by peroxidase-conjugated protein A and developed with ECL. Protein H was taken up by the cells and could be detected in both cytoplasmic and nuclear extracts, whereas protem L was not taken up by the cells (not snown) . Epithelial cells (Detroit 562) were also incubated with protein H (150 μg) and extracts prepared from these cells were immunoprecipitated as described above. Prote H was taken up by the Detroit cells, although a lower amount of prote was detected in the nuclear extracts . Protein H interacts with nucleophosmin/B23 and actin To identify protems interacting with protem H and mediating its uptake, membrane preparations obtained by subcellular fractionation of Jurkat cells were treated with detergent (NP-40). However, no protem H-bmding proteins could be detected in this solubilised material before or following purification by ion-exchange chromatography, gel filtration or affinity chromatography on protem H-Sepharose. To release water soluble peptides from Jurkat cell membrane preparations, papain was used. The solubilised peptides were separated by ion-exchange chromatography and fractions were eluted by a linear sodium chloride gradient (Figure 3A) . The fractions were applied in slots to PVDF membranes and probed with radiolabelled protein H. Fractions 85-87 reacted with the probe, and they were pooled. A portion (20 ml) was labelled with 125 I and subjected to affinity chromatography on protein A-Sepharose (Figure 3B) . The labelled peptides showed no affinity for protein A but when the run-through fractions from protein A-Sepharose were applied to protein H-Sepharose more than 70% of the radioactivity was bound and eluted with 3M KSCN (Figure 3B) . When analysed by SDS-PAGE and autoradiography, this material (peak II) contained two major bands of 18 and 54 kDa, respectively. The run-through material (peak I) gave rise to a smgle band with a molecular mass of approximately 16 kDa. Unlabeleα pool 85-87 material was now purified on protem H-Sepharose followed by SDS-PAGE. After staining, the 18 and 54 kDa Pands (see Figure 3C) were cut out of the gel, digested with trypsm and separated by HPLC. The ammo acid sequences shown in Figure 3C could be determined from HPLC peaks and demonstrated that Poth bands contamed nucleophosmιn/B23 (NPM) , a prote known to shuttle between the cytoplasm and the nucleus (Borer et al., 1989). Monomeric NPM has a molecular mass of 32 kDa out the protein is known to form oligomers (Schmidt-Zachmann et al., 1987; Herrera et al., 1996) , including dimers of 70 kDa also under denaturing conditions (see Umekawa et al., 1993 and Figure 3D). Therefore the 54 kDa band probably consists of dimers of NPM fragments generated by papam cleavage whereas the 18 kDa fragments do not form multimers m SDS-PAGE. Intact NPM and two fragments of NPM covering the NH 2 ~ and COOH-termmal halves of NPM, respectively, were generated by PCR and in vi tro translation. These 35 S-methιonιne- labelled peptides were separated by SDS-PAGE followed by autoradiography (Figure 3D, left) . As mentioned above, NPM has a tendency to form dimers-oligomers (Schmidt- Zachmann et al., 1987; Umekawa et al., 1993; Herrera et al., 1996). This property is evident for the intact molecule giving rise to bands of 35 and 70 kDa corresponding to monomers and dimers. In case of the NH2~ terminal fragment with an apparent molecular mass of 18 kDa, a band corresponding to a trimer of 54 kDa is seen, whereas no distinct oligomers are present m lane 3 where the COOH-termmal fragment was run. This is consistent with previous observations demonstrating that the COOH- termmal part of NPM is not essential for oligomerization (Herrera et al . , 1996). When the three NPM peptides were subjected to affinity purification on protem H- Sepnarose, intact NPM and the NH,-terminal fragment pound to orotein H. The COOH-termmal fragment, however, did no. show affinity for protem ri-Sepharose (Figure 3D, riσnt) . These results and the fact that the 18 kDa NH - terminal papam fragment of NPM shown in Figure 3C, also has affinity for protein n, map the binding of protem H to the NH -terminal part of NPM. As the COOH-termmal region of NPM contains the signals essential for its localization to the nucleolus (Wang et al., 1993), bmdmg of protem H snould not interfere with the targeting of NPM. Using fragments of protein H in competitive bmdmg experiments the region of protem H interacting with NPM was identified. Prote ri was immobilized on Sepharose and radiolabelled NPM (pool 85-87) was added. 80-90 percent of the radioactivity was bound to the Sepharose. As demonstrated in Figure 3E this bmdmg was inhibited by unlabeled protem H and by fragments A and AB of protem H, whereas the effect of protem A was at background level also at high concentration. The mnibition with the NH2 _ termιnal fragment AB, wnich is an even more efficient inhibitor than intact protem H, maps the binding of NPM to this region. The membrane material subjected to papam digestion was obtained by a two-step centrifugation procedure where the supernatant following the final centrifugation at 105000 g represents a cytoplasmic fraction. Also this material was subjected to affinity chromatography on protein H- Sepharose. A dominating band with an apparent molecular mass of 40 kDa was eluted, and NH 2 -termιnal ammo acid sequencing established that the band was actm. Nucleophosmin is co-precipitated with protein H. 1 x 10 6 Jurkat cells were incubated with protem H (150 μg) for various timepomts and in order to analyse if nucleophosmin could be coprecipitated with protem H, nuclear extracts were prepared. The extracts were precleared with glyc e-Sepharose and immunoprecipitated using anti-protem H F (ab ' ) 2 ~Sepharose . Precipitated materials were run on SDS-PAGE and blotted to a PVDF membrane. The membrane was proPed with polyclonal antibodies against recombinant nucleophosmin, followed by peroxidase-conjugated prote A and developed with ECL. Nucleophosmin could be detected in the nuclear extracts. Thus, nucleophosmin could be coprecipitated using antibodies against protein H demonstrating an m vivo interaction between nucleophosmin and protem H. Identification of nuclear proteins interacting with protein H Unlike the homogeneous nuclear stammg seen with protein H, anti-NPM antibodies detect a granular accumulation of NPM in nucleoli (Borer et al., 1989). To investigate whether protem H after the entry mto the nucleus, presumably together with NPM, interacts with nuclear proteins, nuclear extracts from Jurkat cells were run on protein H-Sepharose. Several bands were eluted (see Figure 4, STAIN, lane 2) but when probed with radiolabelled protem H, only three reacted with the probe (Figure 4, BLOT, lane 2). These bands have apparent molecular masses of 39, 42 and 80 kDa, respectively. The 39 and 80 kDa bands (I and III, respectively) were identified as the SET protem by microsequencmg. This protein was initially described as an oncogene product fused to a protem called CAN (v. Lindern et al . , 1992). Three tryptic fragments each of the 39 and 80 kDa bands were subjected to NH2-termιnal sequencmg and all sequences were related to the SET protem (Figure 4, lower section) . This fact and the molecular mass of the 80 kDa band, suggest that it represents a SET dimer. The amino acid sequence of the 42 kDa band (band II, Figure 4) identified this band to be heterogeneous nuclear ribonuclear protein (hnRNP) A2/B1, a member of the hnRNP family (Dreyfuss et al., 1993). Further analyses and comparison between the interactions of protein H with actin, NPM and the nuclear proteins To analyse the interactions between protein H and the various intracellular proteins in more detail, plasmon resonance spectroscopy was utilized. In these experiments different amounts of protein H were applied and left to interact with immobilized actin, NPM or with immobilized protein H-binding nuclear proteins, to the level of saturation (Figure 5A) . The NPM used in these experiments corresponds to the material shown in Figure 3C, and to create an experimental situation similar to in vivo conditions, a mixture of the nuclear proteins interacting with protein H was used for both plasmon spectroscopy and competitive binding experiments (see Figure 4, STAIN, lane 2 ) . Figure 5A shows typical sensorgrams for the interactions between protein H-actin, protein H-NPM and protein H- nuclear proteins. On the basis of these experiments, dissociation and association rates were calculated, and used to determine association and dissociation constants (Figure 5B) . The data demonstrate that protein H has high affinity for actin but also readily dissociates from the complex, and that protein H has a higher association rate and a considerably slower dissociation rate for the nuclear proteins as compared to NPM. Also, competitive binding experiments in which NPM and the nuclear proteins simultaneously compete for the binding of protein H, showed that unlabeled nuclear proteins more efficiently inhibited the interaction between radiolabelled NPM and protein H-Sepharose, than unlabeled NPM itself . In contrast, actin did not interfere with NPM-protein H binding (Figure 5C) and neither did actin interact with immobilized NPM (Figure 5A, middle section). In none of these experiments did staphylococcal protein A show affinity for actin, NPM or the nuclear proteins (Figure 5 A and C) . In summary, the data on the binding kinetics provide an explanation for the release of protein H from its complex with NPM, and its nuclear accumulation as a result of the binding to the nuclear proteins SET and hnRNP A2/B1. Soluble protein H has a cytostatic effect on murine B cells The interaction with the SET protein, a putative transcription factor and oncogene product, and hnRNP A2/B1, a molecule participating in mRNA processing, suggested that protein H could interfere with various cell functions and that metabolically active cells could be particularly sensitive to protein H. It has been shown that protein H interacts also with murine lymphocytes (Axcrona et al., 1995), and the effect of protein H on the proliferation of these cells was therefore investigated. Initially we investigated whether protein H when added to LPS-stimulated murine B cells, was transported to the nucleus, and Western blot experiments demonstrated that this was the case (Figure 6A) . There is no indication that protein H is degraded on its way from the exterior of the cell into the nucleus. Thus, the molecular mass of protein H identified in the medium, the cytoplasm and the nucleus is very similar if not identical. As a control, an identical PVDF membrane as in Figure 6A was incubated with pre-immune serum followed by peroxidase-conjugated protem A. No signals were obtained. Following 24 hours of incubation with protein H, the cytoplasm contained 1.4, and the nuclei 2.4ng of protem H per 10 B cells. Moreover, addition of prote H to the LPS-stimulated B cells, inhibited proliferation measured as [ H]Tdr-uptake n a dose dependent manner (Figure 6B) . A 50 percent inhibition was recorded at the highest protem H concentration tested (50 μg/ml). As determined by morphology and DNA laddering, prote H did not induce apoptosis in tne LPS-stimulated B cells. Legends to figures Figure 1. Binding of protein H to the surface of human peripheral blood lymphocytes and the human Jurkat T cell line determined by FACS analysis . (A) Stammg of T cells with CD3, CD4, and CD8 versus prote H. Granulocytes were gated out with side scatter/forward scatter and stained with prote H. (B) Jurkat T cells were stained with protem H and CD45. Background stammg is shown with FITC avidin and CD3 on the granulocyte gated cells and with gl-FITC/g2-PE antibodies on Jurkat cells. Figure 2. Uptake and nuclear accumulation of protein H in Jurkat T cells. Jurkat T cells were incubated with biotinylated proteins H or A, cytospmned and stained with FITC coupled avidin. (A) Incubation with prote H for four hours and (B) for eight hours. (C) Incubation with protein A for eight hours . Figure 3. Protein H interacts with nucleophosmin . (A) Membrane preparations from Jurkat T cells were digested with papain and the solubilised peptides were subjected to FPLC on a Mono-Q column. Fractions (0.5 ml) eluted with a linear NaCl gradient were analysed for protein H-binding activity in a slot binding assay, and fractions 85-87 reacted with radiolabelled protein H. (B) Radiolabelled pool 85-87 material was run on protein A- Sepharose without showing affinity (left). In the right section the pooled fractions of the run-through peak from protein A-Sepharose were subjected to a protein H- Sepharose column. (C) Peak fractions of peaks I and II from protein H-Sepharose were separated by SDS-PAGE (10% gel), followed by autoradiography . Unlabeled pool 85-87 material was run in parallel. This gel was stained and bands marked by the arrows were cut out. The peptides of the bands were digested with trypsin and tryptic fragments were separated by HPLC. NH2~terminal sequences could be determined from one HPLC peak each of the two bands. These sequences established that both bands contained NPM. Numbers indicate amino acid residue positions in the NPM sequences . (D) In vi tro translated and S-methionine-labelled NPM peptides were separated by SDS-PAGE (13.6% gel). The gel was dried and subjected to autoradiography (left). Lane number corresponds to the peptide run and the peptides are shown schematically in the lower part of the figure. In the COOH-terminal peptide 3, X indicates putative nuclear localization signals. The three radiolabelled peptides were separately applied to protein H-Sepharose. Following extensive washing, bound material was eluted with 3M KSCN, dialyzed against PBS, concentrated and run on SDS-PAGE. The gel was dried and autoradiographeo (right) . (E) Mapping of the NPM-bmdmg region of protem H by competitive inhibition. The bmdmg of I-labelled NPM to protem H immopilized on Sepharose was inhibited with different amounts of unlabeled mtact protem H, fragments AB and A of protem H, or protein A. Figure 4. Identification of nuclear proteins interacting with protem H. A nuclear extract was prepared from Jurkat T cells (lane 1). The extract was precleared with glycme-Sepharose followed by incubation with prote H-Sepharose. After extensive washing protems bound to the protem H- Sepharose were eluted with 3 M KSCN, dialyzed against PBS and separated by SDS-PAGE (lane 2) . Two identical gels (10%) were run simultaneously; one was stained with Coomassie blue (STAIN), one was blotted onto a PVDF membrane and probed with 125 I-labelled protein H (BLOT) . Material corresponding to the three bands indicated was submitted to trypsm digestion, HPLC and NH 2 -termmal sequencing. Three sequences were obtained from each of bands I and III, showing identity to the SET protein. Band II gave rise to two sequences found in hnRNP A2/B1. The sequences are shown in the lower part of the figure, and numbers indicate where homologous residues in the SET and hnRNP A2/B1 are found. Figure 5. Analysis of the binding of protein H to nucleophosmin and nuclear proteins . (A) Overlay plots of the binding of protems H and A to immobilized actm (left) , NPM (middle) or nuclear proteins (right) using plasmon resonance spectroscopy. Increasing concentrations of protem H were applied for 3 mm. each during association pnase. Dissociation of bound proteins was measured (expressed in resonance units, RU) following injection of buffer alone. Affinity rates and dissociation constants for the interactions oetween protem H and actm, immobilized NPM or nuclear protems are as follows (values are mean ± standard deviation from three experiments). 125. (B) Competitive inhibition of the binding of I-labelled NPM to protein H-Sepharose with different amounts of unlabeled NPM, nuclear protems, protein A or actin. Figure 6. Nuclear uptake and cytostatic effect of protein H (A) 7x 10 purified murine B cells -were incubated with LPS and protem H for 24 hours. Medium (1), cytoplasmic material (2), nuclear extract (3) , and protem H (4) were run on SDS-PAGE and stained with Coomassie (left) or blotted to a PVDF memprane (right) . The blotteα membrane was probed with an anti-prote H antiserum, followed by peroxidase-conjugated protem A and developed with ECL. (B) Inhibition of proliferation of murine splenic B cells in response to proteins H and A. Figure 7. Schematic representation of protein H. Sequence Information Given below are the cDNA (SEQ ID No.5) and ammo acid (SEQ ID No.6) sequences of protein H. The boundaries of the S, A, Cl, C2, C3 and D regions are marked, as are the N-termini of the alternative forms of protein H. ATG ACT AGA CAA CAA ACC AAG AM Met Thr Arg Gin Gin Thr Lys Lys -41 Signal peptide (Region S) AAT TAT TCA CTA CGG AM CTA AM ACC GGT ACG GCT TCA GTA GCC GTT Asn Tyr Ser Leu Arg Lys Leu Lys Thr Gly Thr Ala Ser Val Ala Val GCT TTG ACC GTT TTG GGC GCA GGT TTT GCA MC CM ACA ACA GTT MG Ala Leu Thr Val Leu Gly Ala Gly Phe Ala Asn Gin Thr Thr Val Lys GCG|GM GGG GCT MA ATT GAT TGG CM GM GAG TAT AM MG TTA GAC Ala I Glu Gly Ala Lys He Asp Trp Gin Glu Glu Tyr Lys Lys Leu Asp -1 |1 Mature protein, Region A GM GAT MT GCT MA CTT GTT GAG GTT GTT GM ACC ACA AGT TTG GM Glu Asp Asn Ala Lys Leu Val Glu Val Val Glu Thr Thr Ser Leu Glu MC GM MA CTC MG AGT GAG MT GAG GAG MT MG MA MT TTA GAC Asn Glu Lys Leu Lys Ser Glu Asn Glu Glu Asn Lys Lys Asn Leu Asp AM CTT AGC AM GM MT CM GGA MG CTC GM MA TTG GAG CTT GAC Lys Leu Ser Lys Glu Asn Gin Gly Lys Leu Glu Lys Leu Glu Leu ASD TAT CTC AM MA TTA GAT CAC GAG CAC AM GAG CAC CM MA GM CM Tyr Leu Lys Lys Leu Asp His Glu His Lys Glu His Gin Lys Glu Gin CM|GM CM GM GAG CGA CM MA MT CM GM CM TTA GM CGT MA Gin IGlu Gin Glu Glu Arg Gin Lys Asn Gin Glu Gin Leu Glu Arg Lys 80 j81 Region B TAC CM CGA GM GTA GM MA CGT TAT CM GM CM CTC CM MA CM Tyr Gin Arg Glu Val Glu Lys Arg Tyr Gin Glu Gin Leu Gin Lys Gin CM CM TTA GM ACA GM|MG CM ATC TCA GM GCT AGT CGT MG AGC Gin Gin Leu Glu Thr Gl u | Lys Gin He Ser Glu Ala Ser Arg Lys Ser 117 j 118 Region Cl CTA AGC CGT GAC CTT GM GCG TCT CGT GCA GCT AM MA GAC CTT GM Leu Ser Arg Asp Leu Glu Ala Ser Arg Ala Ala Lys Lys Asp Leu Glu GCT GAG CAC CM MA CTT GM GCT GAG CAC CM MA CTT AM GM|GAC Ala Glu His Gin Lys Leu Glu Ala Glu His Gin Lys Leu Lys GluJAsp 158 j 159 Region C2 AM CM ATC TCA GAC GCA AGT CGT CM GGC CTA AGC CGT GAC CTT GM Lys Gin He Ser Asp Ala Ser Arg Gin Gly Leu Ser Arg Asp Leu Glu GCG TCT CGT GCA GCT AM MA GAG CTT GM GCA MT CAC CM MA CTT Ala Ser Arg Ala Ala Lys Lys Glu Leu Glu Ala Asn His Gin Lys Leu GM GCT GAG CAC CM MA CTT AM GM| GAC AM CM ATC TCA GAC GCA Gl u Al a Gl u Hi s Gi n Lys Leu Lys Gl u |Asp Lys Gi n H e Ser Asp Al a 200 j 201 Region C3 AGT CGT CM GGC CTA AGC CGT GAC CTT GM GCG TCT CGT GCA GCT AM Ser Arg Gi n Gly Leu Ser Arg Asp Leu Gl u Al a Ser Arg Al a Al a Lys AM GAG Cπ GM GCA MT CAC CM MA Cπ GM GCA GM GCA AM GCA Lys Gl u Leu Gl u Al a Asn Hi s Gi n Lys Leu Gl u Al a Gl u Al a Lys Al a CTC AM GM|CM πA GCG AM CM GCT GM GM Cπ GCA AM CTA AGA Leu Lys GluJGln Leu Ala Lys Gin Ala Glu Glu Leu Ala Lys Leu Arg 242 j 243 Region D GCT GGA AM GCA TCA GAC TCA CM ACC CCT GAT ACA AM CCA GGA MC Ala Gly Lys Ala Ser Asp Ser Gin Thr Pro Asp Thr Lys Pro Gly Asn AM GCT Gπ CCA GGT AM GGT CM GCA CCA CM GCA GGT ACA|AM CCT Lys Ala Val Pro Gly Lys Gly Gin Ala Pro Gin Ala Gly Thr | Lys Pro 2851286 Approx C-terminus of protein H cleaved from S. pyogenes ] MC CM MC MA GCA CCA ATG MG GM ACT MG AGA CAG πA CCA TCA Asn Gin Asn Lys Ala Pro Met Lys Glu Thr Lys Arg Gin Leu Pro Ser C-terminus of protein H produced in ACA GGT|GM ACA GCT MC CCA πC πC ACA GCG GCA GCC Cπ ACT Gπ Thr Gl IGlu Thr Ala Asn Pro Phe Phe Thr Ala Ala Ala Leu Thr Val 3051306 E. Co l i I ATG GCA ACA GCT GGA GTA GCA GCA Gπ GTA AM CGC MA GM GM MC Met Ala Thr Ala Gly Val Ala Ala Val Val Lys Arg Lys Glu Glu Asn 335 C-terminus of full, mature protein H References Akerstrδm, B., and Bjόrck, L. (1989). Protein L: an immunoglobulin light chain-binding bacterial protein. Characterization of binding and physicochemical properties. J. Biol. Chem. 264, 19740-19746. Akesson, P., Cooney, J. , Kishimoto, F., and Bjorck, L. (1990) . Protein H - a novel IgG binding bacterial protein. Mol. Immunol. 21, 523-531. Akesson, P., Schmidt, K.-H., Cooney, J. , and Bjorck, L. (1994) . Ml protein and protein H: IgGFc and albumin- bindmg streptococcal surface proteins encoded by adjacent genes. Biochem. J. 300, 877-886. Altschul, S.F., Gish, ., Miller, W., Myers, E. ., and Lipman, D.J. (1990). Basic local alignment search tool. J. Mol. Biol. 215, 403-410. Axcrona, K. , Bjorck, L., and Leanderson, T. (1995). Multiple ligand interactions for bacterial immunoglobulm-bmdmg protems on human and murine cells of the hematopoetic lineage. Scand. J. Immunol. 42, 359- 367. Berge, A., and Bjorck, L. (1995). Streptococcal cysteine proteinase releases biologically active fragments of streptococcal surface protems. J. Biol. Chem. 270, 9862- 9867. Borer, R.A. , Lehner, C.F., Eppenberger, H.M., and Nigg, E.A. (1989) . Major nucleolar protems shuttle between nucleus and cytoplasm. Cell 56, 379-390. Dreyfuss, G., Matunis, M.J., P ol-Roma, S., and Burd, CG. (1993) . hnRNP protems and the biogenesis of mRNA. Ann. Rev. Biochem. 62, 289-321. Frick, I.-M., Akesson, P., Cooney, J. , Sjobnng, U., Schmidt, K.-H., Gomi, H., Hattori, S., Tagawa, C, Kishimoto, F., and Bjorck, L. (1994). Protem H- a surface protem of Streptococcus pyogenes with separate binding sites for IgG and albumin. Mol. Microbiol. 12, 143-151. Fπck, I.-M., Crossin, K.L., Edelman, G.M., and Bjorck, L. (1995) . Prote H- a bacterial surface protem with affinity for both immunoglobulin and fibronectm type III domains. EMBO J. 14 , 1674-1679. Herrera, J.E., Correia, J.J., Jones, A.E., and Olson, M.O.J. (1996). Sedimentation analyses of the salt- and divalent metal ion-induced oligomerization of nucleolar protein B23. Biochemistry 35, 2668-2673. Herrmann, C, Volknandt, ., ittich, B., Kellner, R. , and Zimmermann, H. (1996). The major vault protem (MVP100) is contained in cholinergic nerve terminals of electric ray electric organ. J. Biol. Chem. 271, 13908- 13915. Herwald, H., Collin, M. , MYller-Esterl, . , and Bjorck, L. (1996). Streptococcal cysteine proteinase releases kinins: a novel virulence mechanism. J. Exp. Med. 184, 665-673. Herwald, H., Dedio, J. , Kellner, R. , Loos, M., and MYller-Esterl, . (1996) . Isolation and characterization of the kininogen-binding protein p33 from endothelial cells. Identity with the gClq receptor. J. Biol. Chem. 271, 13040-13047. Holm, S.E., Norrby, A., Bergholm, A.M., and Norgren, M. (1992) . Aspects of pathogenesis of serious group A streptococcal infections in Sweden, 1988-1989. J. Infect. Dis. 1 66, 31-37. Mirkovitch, J. , Mirault, M.E., and Laem li, U.K. (1984). Organization of the higher-order chromatin loop: specific DNA attachment sites on nuclear scaffold. Cell 39, 223-232 Schmidt-Zachmann, M., HΫgle-Dόrr, B., and Franke, . . (1987). A constitutive nucleolar protein identified as a member of the nucleoplasmin family. EMBO J. 6, 1881-1890. Umekawa, H., Chang, J.-H., Correia, J.J., Wang, D. , Wingfield, P.T., and Olson, M.O.J. (1993). Nucleolar protein B23: bacterial expression, purification, oligo erization and secondary structures of two isoforms. Cell. Mol. Biol. Res. 39, 635-645. v. Lindern, M. , v. Baal, S., Wiegant, J. , Raap, A., Hagemeijer, A., and Grosveld, G. (1992). Can, a putative oncogene associated with myeloid leukemogenesis, may be activated by fusion of its 3' half to different genes: characterization of the set gene. Mol. Cell. Biol. 12, 3346-3355. Wang, D. , Umekawa, H., and Olson, M.O.J. (1993). Expression and subcellular locations of two forms of nucleolar protein B23 in rat tissues and cells. Cell Mol. Biol. Res. 39, 33-42. Wang, D. , Baumann, A., Szebeni, A., and Olson, M.O.J. (1994). The nucleic acid binding activity of nucleolar protein B23.1 resides in its carboxyl-terminal end. J. Biol. Chem. 269, 30994-30998.

Claims: C AIMS 1. A nuclear delivery construct comprising: (i) protein H or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell; and associated therewith (ii) one or more other components whose targeting to the nucleus of the eukaryotic cell is desired. 2. A nuclear delivery construct according to claim 1 wherein the fragment or derivative of protein H comprises the A region of protein H, or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell. 3. A nuclear delivery construct according to claim 2 wherein the fragment or derivative of protein H comprises the AB region of protein H, or a derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell. 4. A nuclear delivery construct according to any one of the preceding claims comprising, as component (i), a fragment or derivative of protein H which is capable of being targeted to the nucleus of a eukaryotic cell but does not have a cytostatic effect on the cell. 5. A nuclear delivery construct according to any one of the preceding claims wherein component (ii) is a -ou- poiypeptide, nucleic acid, small molecule drug or a liposome 6. A nuciear delivery construct accordmg to claim 5 wherein component (ii) is a polypeptide and the construct is m the form of a fusion protem. . A nuclear delivery construct according to any one of claims 1 to 6 wnerein components (i) and (n) are covalently or non-covalently associated. 8. A pnarmaceutical composition comprising a nuclear delivery construct as defined in any one of the preceding claims; and a pnarmaceutically acceptable carrier . 9. A nuclear delivery construct as defined m any one of claims 1 to 7 for use in a method of treatment of the numan or animal body, or for use in a method of diaαnosis . 10. Use of protein H or a fragment or derivative thereof that is capable of being targeted to the nucleus of a eukaryotic cell in the manufacture of a medicament for the treatment of the human or animal body in which a construct as defined in any one of claims 1 to 7 is targeted to the nucleus of a eukaryotic cell. 11. Use of a nuclear delivery construct as defined any one of claims 1 to 7 in the manufacture of a medicament for the treatment of disease of the human or animal body in which the construct is targeted to the nucleus of a eukaryotic cell. - 6 ± - 12. Use accordmg to claim 10 or 11 wnerein tne construct is targeted to the nucleus of a cell m whicn nucleophosmin (NPM) /B23 is up-regulated . 13. Use according to claim 10, 11 or 12 wherem component ) o the construct interacts with actm, NPM/B23, protem SET or hnRNP A2/B1. 14. Use accordmg to any one of claims 11 to 13 wherein the cell is a tumour cell or a proliferating cell. 15. Use according to any one of claims 10 to 14 where the ceil ±s a virus-infected cell. 16. Use accordmg to any one of claims 10 to 15 wherem the cell is a lymphocyte. 17. Use accordmg to any one of claims 10 to 16 where component (ii) of the construct is a nucleic acid encoding a protem, and targeting to the nucleus effects gene therapy of the cell. 18. A nucleic acid sequence encodmg a fusion protem accordmg to claim 6. 19. A vector comprising a nucleic acid sequence accordmg to claim 18. 20. A cell comprising a nucleic acid sequence according to claim 18 or a vector accordmg to claim 19. 21. A method of producmg a fusion accordmg to claim 6 comprising expressmg a nucleic acid sequence accordmg to claim 18 in a cell, and recovering the fusion protem thus obtained. 22. A method of treating a disease of the human or animal body by targeting a construct as defined in any one of claims 1 to 7 to the nucleus of a eukaryotic cell, comprising administering an effective amount of the construct to a human or animal subject. 23. A method according to claim 18 wherein the disease is a tumour or a viral infection.

Inventors: AXCRONA EUGEN JAN KAROL, BJORCK LARS HENRIK, FRICK INGA-MARIA, LEANDERSSON TOMAS BORJE, AXCRONA, EUGEN, JAN, KAROL, BJORCK, LARS, HENRIK, FRICK, INGA-MARIA, LEANDERSSON, TOMAS, BORJE
Applicants: ACTINOVA LTD, AXCRONA EUGEN JAN KAROL, BJORCK LARS HENRIK, FRICK INGA MARIA, LEANDERSSON TOMAS BORJE, ACTINOVA LIMITED, AXCRONA, EUGEN, JAN, KAROL, BJORCK, LARS, HENRIK, FRICK, INGA-MARIA, LEANDERSSON, TOMAS, BORJE
Application year: 1998
Main classification: C12N15
IPC codes: A61K31, A61K38, A61K47, A61K48, A61P31, A61P35, C07K14, C12N5, C12N15, C12P21, C12R1