WO1994026876A1

WO1994026876A1 - Human t cell monoclone, process for its production and its use, diagnostic of infectious diseases, autoimmune diseases, t-cell mediated allergies and cancer

Info

Publication number: WO1994026876A1
Application number: PCT/EP1994/000742
Authority: WO
Inventors: Jozephus Carolus Martha Raus; Jingwu Zhang
Original assignee: Dr. L. Willems-Instituut
Priority date: 1993-05-14
Filing date: 1994-03-10
Publication date: 1994-11-24
Also published as: EP0698087A1; AU6376194A; CA2162853A1; JPH09500261A; IL108926A0

Abstract

The present invention concerns a human T cell monoclone which is highly proliferative and antigen mono-specific. The present invention is also related to the process for the production of the human T cell monoclone according to the invention and to the use of human T cell monoclone according to the invention for the treatment of infectious diseases, autoimmune diseases, T cell mediated allergies and cancer.

Description

HUMAN T CELL MONOCLONE, PROCESS FOR ITS PRODUCTION AND ITS USE, DIAGNOSTIC NFECTIOUS DISEASES, AUTOIMMUNE DISEASES, T-CELL MEDIATED ALLERGIES AND CANCER

Field of the Invention

This invention is in the field of immunology, im unotherapy and immunodiagnosis. More specifically, the invention is directed to highly proliferative and antigen-specific T-cell monoclones and a process for its production and its use for the treatment and diagnosis of infectious diseases, autoimmune diseases, T-cell mediated allergies and cancer. Background of the invention and state of the art

The immune system protects the host against foreign intruders (antigens) or harmful agents. It is regulated in a sophisticated network, comprising among others T cells and B cells which are programmed to carry out specific tasks. An inappropriate functioning of the immune system can lead to an immune deficiency, as observed in AIDS, or to a norn balanced immune regulation, as observed in autoimmune diseases. T cells play a major role in the control of the immune system. Many immune-related diseases known to-day are associated with a deficient or abnormal T cell function.

Recent advances in the methodology for establishing antigen-specific T cell lines in vitro have helped a great deal in our understanding of the molecular and cellular immunology. These advances have made it possible to analyze the T cell receptor genes and the mechanisms by which the T cell repertoire diversity is generated and they have provided valuable information on the role of immune-response gene products in antigen presentation. In particular, clonal analysis of antigen-specific T cells has provided an opportunity to define the pathologic role of certain T cell populations in the pathogenesis of several human diseases. Ground rules for T cell recognition of proteins and synthetic peptides are now being established. On the basis of this information it is possible to design vaccines that will elicit either MHC Class I or Class II restricted T cell immunity. Moreover, in vit-jro generated antigen-specific T cell lines and clones can be of enormous practical help to identify disease mechanisms and to develop immunotherapeutic and immunodiagnostic strategies.

There are several groups of human diseases where antigen-specific T cell lines and clones could be of valuable help in designing an effective treatment. Autoimmune diseases, in particular, are a group of diseases sharing a common feature, that is, a deficit in the immune regulation of autoreactive T cells, (reviewed by Brostoff et al. eds. Clinical Immunology, Gower Medical Publishing, London-New-York, 1991) . Examples of human autoimmune diseases include Graves' disease, multiple sclerosis (MS) , rheumatoid arthritis (RA) , Myasthenia gravis (MG) , type I diabetes etc. In all known autoimmune diseases, autoreactive T cells or B cells producing autoantibodies are activated and clonally expanded to mount an attack on target tissues of the host. The process often leads to a recruitment of inflammatory cells, including macrophages, gamma delta T cells and T cells capable of producing inflammatory cytokines, followed by a destruction of the tissues involved (reviewed in Deodhar et al., Clin. Biochem. 25, 181, 1992).

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system, characterized by infiltrations of T lymphocytes and macrophages into white matter of the brain and by locally produced inflammatory cytokines and antibodies in the central nervous system (Selmaj et al., Ann. Neurol. 23, 339, 1988; Cross et al. , J. Neuroimmunol. 33, 237, 1991). These processes are associated with de yelinations and neurological dysfunctions. Most often the infiltrating cells are autoimmune in nature and they act as effectors in a process whereby self proteins are recognized and myelin tissue is destroyed. Autoimmune mechanisms mediated by autoreactive T cells hold a central position in a cascade of events leading to demyelination (Reviewed in Zhang et al., Intern. Rev. Immunol. 9, 183, 1992).

Our knowledge of MS and other autoimmune diseases is largely guided by studies in experimental animals. Experimental Autoimmune Encephalomyelitis (EAE) is a paralytic disease of ->the central nervous system, which shares many similarities with MS. It therefore is generally regarded as an animal model for MS. EAE can be induced by activated T cells specific for MBP or Proteolipid Protein (PLP) . In humans, potential pathologic effects of MBP-specific T cells can be illustrated in post-vaccination encephalomyelitis which develops in individuals who have received a rabies vaccine prepared from infected rabbit brain. Similar to experimental animals, MBP- specific T cells occur at an increased frequency in cerebrospinal fluid of patients with MS. These autoreactive T cells isolated from peripheral blood of patients are found in an activated state, suggesting their role in the disease process. Because of the active involvement of the immune system several current treatments of MS are based on non-specific immune suppression. However because of lack of specificity these treatments most often are associated with severe side-effects.

If MS is an inflammatory autoimmune disease mediated by autoreactive T cell responses to myelin antigens, it is theoretically feasible to design an immunotherapy to eliminate selectively these pathogenic T cells. This speculation is largely based on studies in the EAE model.

The part of the T cells that distinguishes one T cell or group of T cells from another is the T cell receptor (TCR) . Thus the TCR seems to be the most appropriate target for designing an effective and specific therapeutic strategy. An obvious requirement for the therapy is the specificity of the treatment for the particular TCR involved. This means that the population of pathogenic T cells must be homogeneous with regard to the TCR repertoire for recognizing the autoantigens involved. This condition seems to be met in EAE in Lewis rats and PL/J mice where encephalitogenic MBP-reactive T cells are restricted to limited epitopes on MBP and to a single TCR Vβ gene segment (Burns et al., J. Exp. Med. 169, 27, 1989; Acha-Orbea et al. , Cell 54, 263, 1988). Various therapeutic strategies designed to target either at the TCR or the autoreactive T cells as a whole have shown to be effective in preventing the development of EAE in sensitized animals (Reviewed in Zhang et al., Intern. Rev. Immunol. 9, 183, 1992).

However unlike its animal counterparts, the situation in MS is more complex with respect to the epitope specificity and the TCR gene usage of MBP- specific T cells (Ben-Nun et al. Proc. Natl. Acad. Sci. 88, 2466, 1991). Furthermore the disease is more complicated by the involvement of Major Histocompatibility Complex (MHC) genes which are highly diverse and variable from one individual to another. The MHC gene products are important elements with which T cells are able to recognize an antigen. Thus, before a target structure commonly shared by these pathogenic T cells is defined, a specific immunotherapy would have to be tailored to a particular individual or a group of individuals sharing related MHC genes. Activated MBP-specific T cells, when rendered non virulent, can prevent and treat EAE in experimental animals (Ben-Nun et al., Nature 292, 60, 1981). This procedure is termed T cell vaccination in analogy with icrobial vaccinations to prevent infectious diseases. Both activation and attenuation are required for the vaccine to be effective in treating the disease. Attenuation can be achieved by either chemical modification or irradiation (Ben-Nun et al., Nature 292, 60, 1981). T cell vaccination has been found to be effective in preventing and treating several experimental autoimmune diseases. Whole live or attenuated T lymphocytes have been used as vaccines to treat or prevent, in addition to EAE, Experimental Autoimmune Thyroiditis (EAT) , Adjuvant Arthritis (AA) and Experimental Autoimmune Uveitis (EAU) (Cohen, Immunol. Rev. 94, 5, 1986). Since the fine specificity of vaccination is dictated by the fine specificity of the T cell recognition, the TCR most likely is involved in the therapeutic or preventive effects. For example, two different MBP-specific T cell lines, each reactive to a different epitope of MBP, were found to vaccinate against EAE specifically induced by the particular epitope, indicating some form of anti-idiotypic immunity. However, when attempts were made to isolate clones of anti-idiotypic MBP-specific or thyroglobulin-specific T cells (in a thyroiditis model) from the uncloned cell lines, only clones producing disease, but not resistance, were obtained. This led to the hypothesis that appropriate aggregation or rigidification of cell membranes, by either hydrostatic pressure or chemical cross-linking, would yield cells which could induce protection more consistently. Similarly, low doses (sub-encephalitogenic) of MBP- specific cells were able to induce resistance to lethal EAE. The protective state was termed "counter- autoimmunity". This state involves T cell clones which can specifically proliferate in response to the vaccinating T cells, can suppress effector clones in vitro (non-specifically, presumably through release of a suppressive lymphokine) , and can adoptively transfer counter-autoimmunity in vivo. Such counter-autoimmunity is accompanied by suppressed delayed-type hypersensitivity (DTH) responses to the specific epitope and prevention or remission of clinical disease.

The biologic principles learned from the animal studies may be operating in MS as well, provided autoreactive T cells play a similar pathogenic role in MS. Thus, the immunotherapeutic strategies effective in the treatment of EAE may have provided some clues in designing specific treatments for MS.

Another group of diseases where antigen- specific T cells play an important role in the disease mechanisms are the T-cell mediated allergies such as the nickel-mediated allergy (Kapsenberg, M.L. et al. J. Invest. Dermatol. 98, 59-63, 1992). Eliminating these allergen-specific T cells could be of benefit to reduce the disease symptoms.

A further group of human diseases where antigen- specific T cell clones are currently applied for treatment are cancers. Although the pathogenesis of cancer remains unknown, it is generally accepted that a deficit in the host immunity against cancerous cells plays an important role in the development of malignant tumors (Miescher et al., J. Immunol. 136, 1899, 1986). Although the exact mechanisms why tumor-specific T cells fail to eliminate tumor cells are unknown, current efforts are being made to develop an immunotherapy aimed at an increase of the functional capacities of tumor-specific T cells. In this regard, tumor infiltrating lymphocytes (TIL) harbored at tumor sites attract most interest since they may represent an attempt of the tumor-bearing host to develop an immune attack against the tumor (Vose et al., Se in. Haematol. 22, 27, 1985). TIL are comprised of heterogeneous populations of effector and immunoregulatory lymphocytes and monocytes (Whiteside et al., Int. J. Cancer. 37, 803, 1986). Recent evidence obtained from animal studies has shown that adoptive transfer of TIL into the tumor-bearing host is able to mediate significant anti-tumor effects or even to induce total tumor regression (Rosenberg et al., Science 223, 1318, 1986) . Similarly in humans, tumor-specific T cells can be derived from TIL preparations and are found to lyse tumor targets in an antigen specific fashion. Typically, TIL are isolated from surgical tumor specimens and expanded to 10⁹ - 10¹¹ cells for adoptive transfer into a tumor-bearing recipient. Its potential application as an adoptive immunotherapy is currently being evaluated in pre-clinical studies and clinical trials (Rosenberg et al. ,New.Engl. J.Med.319, 1676, 1988) .

The T-cells that attack foreign antigens, autoantigens and tumors are immunologically important because these T-cells recognize specifically foreign antigens, autoantigens and tumors as their targets, and these specificities can be utilized for therapeutics and diagnostics of the diseases associated with a deficient or badly regulated function of foreign antigen specific T-cells, autoantigen specific T-cells and tumor specific T-cells.

Difficulties in T cell cloning have been a constant challenge to all immunologists to study T cell interactions at the clonal level. Cloning of human T cells by specific antigens has been generally used as the conventional approach. In this technique T cells are stimulated by antigenic peptides processed and presented by antigen-presenting cells. However, it has been a general experience that this T cell activation pathway does not necessarily stimulate every single antigen-specific T cell. There are several lines of evidence suggesting that an inappropriate antigen presentation occurred during the interaction between an antigenic peptide and the T cell receptor induces clonal anergy which renders T cells unresponsive to the antigen (LaSalle et al., J. Exp. Med. 176, 177, 1992). In addition, a culture condition for T cell activation is difficult to optimize since it varies with the individual antigen involved and the functional characteristics of the individual clones. Thus, cloning of human T cells by antigen stimulation is largely hampered by a lower cloning efficiency and, therefore requires higher numbers of T cells for the cloning process. This gives rise to contamination of the clone preparation by other irrelevant cells and to poor growth characteristics.

This is illustrated by our attempt to clone MBP-specific T cells from the blood of human subjects by stimulation with MBP. Although these clones demonstrated clonal responses to a single antigenic peptide and expressed a single phenotype, PCR analysis revealed multiple V/3 gene products, indicating the oligoclonal nature of the clone preparation (Ben-Nun et al., Proceedings of National Academy of Science, 1991). These MBP-specific T cell "clones" usually maintain reactivity to MBP for a short period of time (usually two or three weeks) and subsequently deteriorate in culture. It is likely that repeated stimulation with the antigen induces unresponsiveness of the "clones" by down regulation (LaSalle et al., Journal of Experimental Medicine, 1992) .

Until recently the clonality of the resultant clones was not appropriately analyzed. The term "T cell clone" is ambiguously based upon the completion of a cloning process, usually with a lower cloning efficiency, and the antigen reactivity of the "clone" preparation. Thus in the past, the lack of proof for a unique genetic marker of the clone has added to the suspicion on the true clonality of these "clones" as described in many earlier publications, even though this may not directly affect their experimental outcome. Due to the advances and the implementation of molecular biotechnology, in particular the PCR techniques, in T cell cloning procedures it has been possible to provide more evidence for the monoclonality of a particular cell preparation.

Summary of the invention

The present invention relates to a population of human T cell monoclones which is highly proliferative in the presence of an antigen to which human T cells forming this population are specific. The population of human T cell monoclones is characterized by its full biological purity in that it remains free of contaminating cells at all stages of subsequent culture development.

Preferably, the human T cell monoclone population of the present invention is characterized in that it gives rise to a single TCR V gene expression. It is also characterized in that it possesses a unique TCR V-D-J DNA sequence. Also preferred are T cell monoclone populations comprising cells of either the CD4 or the CD8 phenotypes.

The antigen for which the human T cells of the population of human T cell monoclones of the invention are specific and in the presence of which the population is proliferative is preferably a tumor cell or an immunogenic portion thereof, an auto-antigen. Preferred other antigens include Myelin antigens or immunogenic portions thereof, particularly the Myelin basic protein, the proteolipid protein, the Myelin- associated-glycoprotein, the Myelin-Oligodendrocyte- Glycoprotein and/or mixtures thereof, more particularly an epitope of the 84-102 region or the 149-170 region of the a ino acid sequence of Myelin Basic Protein.

The antigen to which the human T cells forming the population of human T cell monoclones are specific can also be a foreign antigen such as a Tetanus Toxoid antigen or an allergen that is mediating the allergy through T cells.

Also within the scope of the present invention is a method for the production of a population of human T cell monoclones which is highly proliferative in the presence of the antigen to which the human T cells are specific and/or any other T cell stimulating agent, and which is characterized by its full biological purity in that it remains free of contaminating cells at all stages of subsequent culture developement. The method comprises:

1) providing a human T cell line responsive to the antigen;

2) single cell cloning the T cell line and stimulating the resulting T cell clone with a T cell stimulating agent in the presence of autologous or allogeneic feeder cells to produce populations of human T cell monoclones; and

3) selecting the monoclone population having the desired TCR-specific characteristics.

Preferably, the human T cell line used in the method of the present invention is taken from peripheral blood lymphocytes. As for the T cell stimulating agent, it is preferably selected from the group consisting of lectines, preferably PHA and/or ConA, lymphokines, preferably Interleuken-2 (IL-2) and/or a recombinant IL-2 (r-IL2) mitogenic antibodies against CD3 and other cell surface molecules and/or a mixture thereof.

Also within the scope of the present invention is a homogeneous population of T cell receptors from human T cell monoclones forming the population of the present invention or the antigen- specific portion thereof and/or a mixture of selected populations or portions.

Also within the scope of the present invention is a therapeutic agent for the treatment of autoimmune diseases, T-cell mediated allergies, infections and cancer. The therapeutic agent comprises an effective amount of a population or a mixture of selected populations of T cell monoclones according to the invention.

The invention also relates to a vaccine composition for conferring upon humans active immunity against other immune diseases. The vaccine composition comprises an effective amount of a homogenous population of T cell receptors from human T cell monoclones according to the invention or a mixture of selected populations of T cell receptors obtained from the population of human T cell monoclones according to the invention or an antigen-specific portion thereof.

Also within the scope of the invention is a method for the treatment of a patient suffering from a condition caused by one or more antigens associated with this condition and obtainable from a biological sample of the patent. The method comprises vaccinating the patent with an adoptively transferring to the patient an amount of a human T cell monoclone population sufficient to generate the appropriate immune response to at least partially alleviate the condition. The human T cell monoclone population is responsive to the antigen and has a full biological purity in that it remains free of contaminating cells at all steps of culture development.

The invention also relates to a kit for preparing a population of human T cell monoclones which is highly proliferative in the presence of the antigen of the type which may be held responsible of a particularly diagnosed disease and for the subsequent preparation of a population of the identified T cell monoclones. The kit comprises:

1) an essential antigen and its peptide specific to the diagnosed disease in sufficient amounts to generate cell lines responsive to the antigen from a biological sample;

2) means for plating the human T cell lines at very low cell densities;

3) a T cell stimulating agent for growing the human T cells at low density; and optionally

4) protocols and essential reagents for the characterization of the T cell monoclones.

The invention also relates to a diagnostic kit which comprises an appropriate solid support for immobilizing a biological sample containing a specific T cell responsive to an antigen associated with the condition to be diagnosed, means for at least immobilizing the specific T cell on the support and an antibody to a T cell monoclone receptor specific for the antigen associated with the condition to be diagnosed.

The population of human T cell monoclones of the present invention is particularly useful to maintain T cell monoclones in a long term culture in order to reach a sufficient amount of cells to prepare appropriate therapeutic agents. There is a clear need for a diagnostic and a therapeutic agent capable in a specific manner, of detecting, preventing, suppressing and/or treating infectious and immune-related diseases and/or cancer.

The human T cell monoclone population of the present invention can be expanded to a sufficiently high amount to be used either in a diagnostic kit or as a therapeutic agent, such as a vaccine or a preparation of T cells to be used for adoptive immune therapy. The human T cell monoclone population can also be used as a therapeutic agent to prevent, suppress and/or treat infectious and immune-related diseases and/or cancer, without causing generalized suppression of immunity as it is the case with most current immuno-therapeutic and immuno-pharmacological approaches of the state of the art.

The present invention also provides a method for the in vitro preparation of foreign antigen specific, autoantigen specific and tumor specific T cell monoclone populations which minimizes or even eliminates the problems of contaminating cells associated with current methods of the state of the art. SHORT DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the reactivity pattern of a panel of MBP-specific T cell lines to three MBP fragments.

Figure 2 represents the PCR analysis of TCR V/3 gene usage of MBP-specific T cell clones cloned by repeated MBP stimulation (panel A-B) and by PHA stimulation (panel C-D) . Panel E represents single Vβ gene usage of a typical TSL clone cloned by the method of the invention.

Figure 3 illustrates a comparison of the cloning efficiencies of MBP-specific T cell lines by PHA and MBP stimulation.

Figure 4 represents the proliferative responses to the inoculates and control T cells and the changes in the frequency of MBP-specific T cells before and after each inoculation.

Figure 5 represents the relationship of changes in the frequencies of T cells reactive to MBP, TT and inoculates in recipients (GE and CW) and non- recipients (AH and GC) .

Figure 6 represents the functional properties of the anti-clonotypic T cell lines. Figure 7 represents the proliferative response of TSL lines to autologous and allogeneic tumor targets.

Figure 8 represents the cytotoxic activity of the TSL lines against autologous and allogeneic tumor cells, NK-sensitive K562 cell line, and NK-resistant Daudi cell line. The MCF7 cell line is a human breast cancer line.

Figure 9 represent the anti-clonotypic T cell responses to vaccine clones and changes in the estimated frequency of circulating MBP-reactive T cells in six patents with MS, before and after each inoculation.

Figure 10 is a schematic representation of the TCR gene organization and the specific sites within the target TCR potentially eliciting the anti- clonotypic T cell responses.

Detailed description of the invention

The invention relates to antigen-specific T- cell monoclonal populations and their use in diagnosis and treatment of various diseases such as infectious diseases, autoimmune diseases, T-cell mediated allergies and cancer.

Clonotypic regulation is one of the important components of peripheral regularotry mechanisms that keep autoreactive T cells in check. This regulartory network can be boosted by T cell vaccination to therapeutically deplete autoaggressive T cells in autoimmune pathologies, resembling traditional vaccination using attenuated autoreactive T cells as vaccines. For example, cellular and molecular interactions potentially involved in the clonotypic regulatory network result in therapeutic applications of T cell vaccination in human autoimmune diseases, such as multiple sclerosis. Autoreactive T cells recognizing a variety of self-antigens represent part of the normal T cell repertoire and naturally circulate in the periphery. Common in many organ-specific autoimmune diseases, these autoreactive T cells undergo activation and clonal expansion, which represents the hallmark of the pathologic properties of autoaggressive T cells in the induction of autoimmune diseases. Activation of autoaggressive T cells renders them to acquire a different functional state and a homing pattern into the affected organ. Clonal expansion features not only an increase of autoaggressive T cells in their numbers but also a shift of their normally heterogeneous T cell receptor (TCR) repertoire towards an eliciting pathogenic epitope(s). The critical transaction from autoreactivity, a normal physiological state, to autoimmune pathology relates to the interplay between activation and clonal expansion of autoreactive T cells and an improper functioning of regulatory networks that keep them in control. One of the regulatory mechanisms involves the clonotypic network that regulates autoreactive T cells by interacting with their TCR clonotypic determinants. TCR hypervariable epitopes constitute clonotypic markers characteristic for an individual autoreactive T cell clone and recognizable by its regulators. The clonotypic interaction represents the "fine-tuning" of the regulatory network without affecting the remainder of the T cell repertoire. Recent investigations further suggest that such a clonotypic network is naturally operative in vivo and can be up-regulated in a clinical setting to therapeutically deplete autoaggressive T cells.

As pathogenic autoreactive T cells are viewed as pathogens in T cell-mediated autoimmune diseases, they can be used, when rendered avirulent by irradiation or pressure and chemical treatment, as vaccines to prevent and treat the diseases. The principle of T cell vaccination is similar to traditional microbial vaccination against infectious agents. There is evidence that administration of attenuated autoreactive T cells as vaccines induces the regulatory networks to specifically suppress the eliciting autoreactive T cells (Ref. 7) . T cell vaccination is effective in preventing and treating many experimental autoimmune diseases, including experimental autoimmune encephalomyelitis (EAE) , experimental autoimmune uveitis, experimental diabetes model and adjuvant arthritis. The protective effect is long-lasting and specific since the autoreactive T cells used for vaccination only protected against the disease that they are able to induce.

The mechanism underlying T cell vaccination is not completely understood, but is thought to involve clonotypic network regulation directed at clonotypic determinants of a target TCR. Evidence supporting this notion comes from several observations. (1) CD4⁺ and CD8⁺ anti-clonotypic regulatory T cells are induced by and specifically recognize the immunizing clones. (2) These anti-clonotypic T cells are .the major cellular component of the protective mechanism and are capable of conferring a specific protection to naive rats by adoptive transfer. Other regulatory T cells may also contribute to the protection by interacting with cellular markers other than the TCR clonotypes, such as the regulatory T cells identified as anti-ergotypic T cells that respond not to the TCR but to a marker associated with their state of activation.

Variable TCR region(s) involved in triggering the anti-clonotypic T cell responses in vivo are most likely to reside in hypervariable regions, such as complementary determining region-3 (CDR3) or less variable CDR2 regions.

T Cell vaccination offers a unique in vivo setting in which the clonotypic network selects a relevant target epitope(s) to naturally regulate autoreactive T cells. In figure 10, there is provided a schematic representation of the TCR gene organization and the specific sites within the target TCR potentially eliciting the anti-clonotypic T cell responses in vivo.

Regognition of anti-clonotypic T cells to the junctional (CDR3) regions of the target TCR elicits a specific depletion of the immunizing T cell clone in the context of MHC class I molecules. Anti-clonotypic T cells with the other recognition pattern to a "cross- reactive" clonotype probably in CDR2 sequences of the variable regions react with, in addition to the immunizing clone, other T cells sharing the same clonotype.

Structural and functional features of autoreactive T cells in MS and their relevance in development of therapeutic strategies

In EAE, activated encephalitogenic T cells are the direct cause of the disease. Their TCR repertoire towards Myelin Basic Protein (MBP) , a causal autoantigen, is rather limited with respect of both a limited epitope recognition and the V gene usage. Hence, the limited TCR repertoire provides suitable molecular targets for specific therapeutic interventions. Various TCR-based strategies have been developed to target at Vβ gene products or other attacking points within the TCR characteristic for the encephalitogenic T cells.

However, unlike the autoimmune disease model, the complexities of human autoimmune pathologies are often reflected by an obscure identity of eliciting autoantigens and a rather heterogeneous TCR repertoire of the autoreactive T cells involved. In MS, for example, T cell responses to myelin antigens, such as MBP, are implicated in the induction of autoimmune pathology. In contrast to their rodent counterparts, human MBP-reactive T cells display a heterogeneous pattern of TCR V3 genes. These T cells isolated from different MS patients use a broad spectrum of V/3 genes in response to MBP, even though the responses are relatively limited to the two im unodominant regions of MBP, residue 84-102 and residue 143-168. It is of interest to note that the V3 gene usage pattern varies largely among MS patients but it appears to be restricted in a given individual. Studies conducted in the context of the present invention have revealed that the limited V/3 gene usage in a given MS individual rather represents a clonal expansion of MBP-specific T cells, as evidenced by their sharing of unique V-D-J and V-J juntional DNA sequence patterns. An example is given in Table 4 which illustrates a limited clonal origin(s) of MBP-reactive T cells isolated from a patient with MS. Based on these lines of evidence, it is reasonable to propose that MBP-specific T cells in MS undergo activation and clonal expansion that is marked by a skewed TCR repertoire towards a related epitope(s) and certain V gene usage. Consistent with this notion is our recent finding that in vivo activated MBP-reactive T cells often share an identical V-D-J sequence pattern with the clonally expanded population(s) in a given MS patient.

The heterogeneous expression of TCR V gene products among a general MS population would considerably perplex current attempts to develop TCR V gene-based therapeutic strategies. A treatment agent (e.g. a monoclonal antibody on a TCR peptide) designed to target at certain TCR V gene product(s) may be useful in one patient but is not suited for another, which hampers significantly its clinical usefulness. On the other hand, as clonal expansion of very limited MBP-specific T cell populations is a rather profound feature in MS, their restricted TCR repertoire provides a uniform target structure in a given patient even though it varies between individuals. These clonally expanded T cells often account for more than 60%-80% of all MBP-specific T cells in a given individual with MS. Thus, a potential therapy may take the advantage of a predominant marker representative of clonally expanded MBP-reactive T cells but its applicability may be limited to given individuals, reflecting a dilemma in designing a suitable TCR-based therapeutic strategy.

From a therapeutic standpoint, there are two principal ways to halt T cell-mediated autoimmune processes either by blocking and depleting the pathogenic T cells or by boosting pre-existing regulatory mechanisms of the host. A potential drawback inherent in the former approach is that it requires frequent administrations of the remedy and its therapeutic effect is often short-term and diminishes with the withdrawal of the remedy. Thus, there is a need for an active therapy that mobilizes and up- regulates natural regulartory networks of the host to specifically restrain autoaggressive T cells. T cell vaccination appears to merit its place in the development of such a therapeutic strategy for various human pathologies. Furthermore, as a clonally expanded T cell population has a pathologic relevance in autoimmune disease, these T cells bearing a uniform clonotypic marker have an obvious therapeutic potential for immune intervention.

Method for the preparation of a human T cell monoclone population of the invention

A/ Generation of antigen-specific T cell lines

Generally, the T cells used in the production of the monoclone populations of the invention are selected according to the condition to be treated. For example, in the case of autoimmune diseases, patient peripheral blood lymphocytes are used to derive the appropriate T cell lines. In the case of tumor specific lymphocytes, the cells are obtained from tumors excised from patients.

In other situations, it is also possible to develop monoclone populations from T cells found in the anatomic region associated with the condition. Examples of such situations include rheumatoid arthritis for which cells associated with this condition are found in the synovial fluid of the joints, and multiple sclerosis for which associated cells are found in the cerebro-spinal fluid.

In the case of foreign antigen specific T cell monoclone populations, specific cell lines can be generated from peripheral blood lymphocytes. As it will be seen from the examples which follow this description, this procedure was successfully applied to generate T cell lines specific to a Tetanus Toxoid antigen.

Various techniques for human T cell expansion have been described in the prior art. For example, one may refer to Zamvil et al, Nature 319: 355-358, (1985) and Nature 324: 258-260 (1986), Londei et al, Science 228-85-89 (1985), Londei et al Acta Endocrinol. 115 (suppl. 281): 86-89 (1987), Stamenkovic et al, Proc. Natl. Acad. Sci. USA 85: 1179-1183 (1988), Lipoldova et al, J. Autoimmun. 2: 1-13 (1989). However, it will be appreciated that the person skilled in the art can use the techniques referred to above or other methods to generate the appropriate antigen-specific cell lines. Furthermore, the person skilled in the art may also refer to the examples of the present application which provide specific procedures for generating MPB-specific T cell lines from peripheral blood, tumor specific lymphocytes from tumors excised from patients and the generation of Tetanus Toxoid specific T cell lines from peripheral blood. In situations where the T cell lines are isolated from peripheral blood, peripheral blood lymphocytes are isolated and cultured in the presence of the antigen for a period of time ranging from 5 to 10 days. This time may vary depending on the number of reactive cells in the sample, the activation state of the cells, and the potency of the stimulating preparation. All these factors can be adjusted by the person skilled in the art.

The resulting cultures are restimulated with autologous antigen-presenting cells previously irradiated to prevent their proliferation and the antigen. The restimulation time may vary but will usually range between 5 and 12 days. In the case of tumor specific lymphocytes, it can, in some instances, be necessary to use surface-oxydized allogeneic cells to stimulate the lymphocytes periodically in the presence of an appropriate T cell stimulating agent.

The viable T-cell lines are then isolated and restimulated with the autologous antigen-presenting cells in the presence of the appropriate antigen for a period of time ranging from 5 to 12 days. The cell lines are then examined for their specific proliferation in response to the antigen in a proliferation assay.

B/ Single cell cloning of antigen-specific T cells

It is usually difficult to clone out true antigen-specific T cell clones because of problems usually associated with the autologous antigen- presenting cells, low cloning efficiencies and the induction of T cell tolerance during the antigen stimulation process. As a result of these problems, the general approach used to clone T-cells was to use between 10 and 30 cells per well. As a result, the clone preparations are contaminated with unwanted T cells.

In the method of the present invention, the antigen-specific T cells are plated out at very low cell densities in the presence of irradiated autologous or allogeneic antigen-presenting cells and a potent T cell stimulating agent such as PHA and/or ConA, mitogenic antibodies against CD3 and other surface molecules and/or a mixture thereof. The person skilled in the art will appreciate that the T cell stimulating agents set forth above are provided as examples and that other T cell stimulating agents can also be used. During growth, cultures can be refed with fresh culture medium containing lymphocyte growth factors such as IL-2 that can be further expanded by alternate stimulation with the antigen and the T cell stimulating agents referred to above. It is to be noted that, apart from its growth factor propertie, IL-2 can also be used as a T-cell stimulating agent.

The single cell cloning approach is an important aspect of the present invention. Hence, it provides for higher cloning efficiencies, improved growth characteristics which allow for a large scale expansion of the clones, maintenance of antigen specificity after repeated expansions and monoclonality. In fact, with the method of the present invention, it is possible to grow a homogeneous population of several million cells in a period of time of 4 to 6 weeks. The use of a potent T cell stimulating agent avoids the contamination problems encountered with antigen-presenting cells.

Characteristics of the T cell population of the invention

As mentioned previously, the method of the present invention allows the production of homogeneous T cell monoclone populations that can be grown in sufficient amounts to be used in therapy. Of course, the populations of the present invention are not restricted to cells recognizing a single immunogenic epitope or antigen. It is possible to develop cell line populations comprising mixtures of different clones that recognize different epitopes on one antigen. In such situations, it might be necessary at the beginning to conduct parallel single cell clonings in order to initially grow homogeneous populations that recognize a single epitope which can then be combined to generate the appropriate mixture.

A highly proliferative T cell clone can be defined by its stimulation index of at least 10 (CPM in the presence of the antigen/CPM in medium only) , which is measured in a standard 3H-Thymidine uptake assay. Antigen-specific T cells are often tolerized after repeated antigenic challenge or by inappropriate antigen presentation. In this regard the invention offers a practical alternative by alternate stimulation of the clones with the antigen(s) and a non-specific stimulating agent such as PHA. This procedure ensures the specificity and responsiveness of a clone maintained in a long term culture.

The human T cell populations developed using the method of the present invention can therefore maintain a high degree of biological purity by remaining free of contaminating cells after numerous subculturing stages. This biological purity is explained in part by the absence of other cells having the ability to grow in the presence of the antigen to which the desired human T cells are specific. In therapeutic applications, it is important to maintain uniform characteristics in the cells forming the populations in order to ensure constant treatment efficacy. Kit for the identification of human T cell monoclones and for the preparation of populations of human T cell monoclones

The kit can be used for the identification of those human T cell monoclones which are highly proliferative to an antigen of the type which may be held responsible of a particularly diagnosed disease and for the subsequent preparation of a population of the identified human T cell monoclones. Provided that the equipment required for the preparation of T cell vaccines is available on site, clinicians using the kit of the present invention are able to identify, from a biological sample of a patient, specific T cells responsive to a targeted antigen associated with the condition to be treated and to isolate and proliferate these specific T cells in sufficient amounts to use them for vaccination and treatment purposes.

Generally, the kit comprises the antigen, or an immunodominant peptide thereof, required to identify the specific T cell from the biological sample, means for plating the identified human T cell line at very low cell density and a T cell stimulating agent for growing the low density plated specific human T cell. Optional elements that can form part of the kit include reagents to evaluate the proliferation of the specific T cells prior to plating. The choice of these reagents is within the knowledge of the person skilled in the art.

Antigens comprised in the kit preferably include those antigens which are common to most patients suffering from the condition to be treated. It can be the whole molecule or peptides or fragments thereof containing the relevant immunodominant epitopes. Examples of such antigens include:

1) for rheumatoid arthritis: a) Collagen type II (1990 Rheumatol. Int. 10, 21-29 b) Heat Shock Proteins (1991 Int. Immunol. 3, 965-972) c) Superantigens (1991 Proc. Natl. Acad. Sci. 88, 10921-10925)

2) for multiple sclerosis: a) Myelin Basic Protein and immuno¬ dominant epitopes thereof (1992 Ann. Neurol. 32, 330-338 and 1990 Nature 346, 183-187) b) Proteolipid Protein (1994 J. Exp. Med. Vol. 179)

3) for diabetes mellitus type I:

Glutamic acid decarboxylase (1993 J. Exp. Med. 177, 535-540)

4) for allergies: different types of allergens mediated by lymphocytes such as Nickel, poison ivy and rubber, have been identified (1993 Immunology, 3rd edition, Published by Mosby, Editors: E. Roitt, J. Brostoff and D. Male) .

5) In cancer: evidence has been provided for _. antigen specificity of tumor infiltrating T lymphocytes. An example of such antigens has been described in 1993 J. Immunol. 151, 3719-3727.

The means for plating the human T cell lines can be chosen from a relatively large number of devices which can be operated by the person skilled in the art. As for the T cell stimulating agent, it can also be chosen from a wide variety of available compounds. What is required is that the T cell stimulating agent be sufficiently potent to stimulate the development of T cells plated out at very low cell densities. Available compounds include those referred to above such as PHA. However, the person skilled in the art may select other stimulating agents that would provide enhanced growth of T cells plated out at low densities.

In situations where the specific T cell lines can be readily identified from the biological sample or where it is required to have specific T cell monoclones to antigens which are different from one individual to another, the antigen is not an integral component of the kit. In this situation, the antigen-specific T cell lines are developed from biological samples which are related to the condition to be treated. As mentioned previously, in autoimmune diseases, patient peripheral blood lymphocytes are used, in tumor specific lymphocytes, cells obtained from excised tumors are used, in rheumatoid arthritis, cells found in the synovial fluid of the joints are used and in multiple sclerosis, cells found in the cerebro-spinal fluid are used.

Therapeutic formulation and administration of the T cell populations

The therapeutic use of the T cell populations of the present invention in the treatment of diseases or disorders can be accomplished by those skilled in the art using known principles of diagnosis and treatment. One important criterium is that the T cell clone population selected must have good growth characteristics, which permits large scale expansion of the clones to a sufficient amount that can range between 1 x IO⁶ and 1 x IO⁸ cells per clone.

Pharmaceutical compositions are prepared using inactivated cells or by combining inactivated cells to the appropriate carrier, which itself can be an immunological adjuvant. These compositions can be administered by any means that achieves the intended purpose. For example, administration may be subcutaneous, intravenous, intradermal, intramuscular or intraperitoneal. The amount of cells administered as well as the frequency of administration is dependent upon the age, sex, health and weight of the recipient as well as the nature of the effect desired. Generally speaking, between 1 x IO⁵ and 5 x IO⁷ cells can be injected in at least 2 inoculations. The amount of cells administered should be sufficient to induce a substantial proliferative response to the vaccine preparation, preferably after the second inoculation.

For example, a pool of 10⁷-1.5 x IO⁷ irradiated cells can be prepared as a vaccine and injected subcutaneously. The selection of the amount of cells for vaccination can be made on the basis of an effective dose in humans such as described in Zhang et al. Science Vol 261, p. 1451-1454 (1993) or on the basis of an appropriate animal model such as the model described by Ben-Nun et al. in 1981, Nature 292, 60-63.

The number of inoculations necessary to induce the appropriate proliferative response against a particular vaccine clone or a mixture of clones can vary depending on the type of disease, disease state and the immunological state of the patent. Generally, for autoimmune diseases, at least two inoculations of 10⁷-1.5 x 10⁷ irradiated cells administered at 2 to 4 months intervals is sufficient to generate the appropriate response. In some situations, the number of inoculations needed can be higher dependent on the short and long term immune response of the patient to the specific T-cell vaccine and the antigen specificity of other possible pathogenic T-cells involved in the disease mechanism.

The response of the patient to the treatment is evaluated by analyzing the proliferation of anti- clonotypic T cells in patients injected with the T cell population of the invention. Briefly, peripheral blood mononuclear cells are isolated from the patient at different intervals following inoculation and plated out for stimulation to the targeted antigens. If the patient has responded to the treatment, specific regulatory T cells are detectable in the patient. Normally, either CD4+ or CD8+ cell lines are stimulated by the inoculates. However, it is possible that other T cell populations are also induced by the vaccination, not only by exhibiting an inhibitory effect toward the vaccination product but also by driving the regulation network to enhance the suppression.

Diagnostic kit

The T cell monoclone population of the present invention can also be used in the diagnosis of conditions which result from the pathogenic role of these cells.

When it is necessary to provide a diagnosis for a patient suspected of suffering from a particular condition, a biological sample, or a lysate thereof, taken from the patient, is immobilized on a solid support. The presence of a particular pathogenic T cell is then determined by applying a monoclonal antibody directed against a recognized shared sequence of the T-cell receptor. Identification can be performed by various immunostaining techniques such as ELISA and flow cytometry, a well known procedure to those skilled in the art.

The diagnostic kit of the invention therefore comprises a solid support on which the biological sample can be deposited and the relevant T-cells immobilized. It also includes means for at least immobilizing the sample cells on the support. Among the means that can be used to fix the sample cells on the support, one may mention the attachment of the cells on ELISA plates with antibodies (see for example Lymphocytes: a practical approach, Ed. Klaus GGB, pp. 48-54 1987 IRL Press, Oxford, Washington D.C.) or chemical cross-linking (see for example 1990 Anticancer research 10, 271-278).

The kit also comprises a monoclonal antibody or monoclonal antibodies to a specific T cell membrane receptor recognizing one of the antigens associated with the condition to be diagnosed. The antibodies can be obtained by methods known to those skilled in the art. See for example Kohler and Milstein, Nature 256: 495-497, 1975 and US patent 4,376,110. Such antibodies can be of any immunoglobulin class but are preferably of the IgG class. Antibodies can also be prepared from polyclonal antiserum taken from animals immunized with the human T cell monoclone population of the present invention and subjected to various purification techniques known by those skilled in the art. The antibodies used can be labelled with an enzyme, a fluorescent dye or a cheminoluminescent label as is well known to those skilled in the art. Alternatively, the antibodies can be labelled with a DNA fragment that can be amplified by PCR as has been described previously (Sano T et AL. Science, Vol. 259, p. 120-122, 1992).

Monoclonal antibodies of animal origin or fragments thereof or recombinant antibodies containing the antigen binding region of the original antibody can be "humanized" by linking a cDNA molecule encoding the region of the monoclonal antibody to DNA encoding the human constant region, using various approaches described for example in US patent 4,816,567, European patent publication EP 125023, EP 171496 and EP 173494 and PCT publication WO 8601533 and WO 8602671.

An example of the diagnostic kit of the invention is one to be used in the diagnosis of multiple sclerosis. Monoclonal antibodies to shared T cell monoclone receptors specific to immunodominant regions of MBP (residues 84-102 and 143-168 for example) are prepared and fixed on an appropriate support. A biological sample taken from a patient suspected of suffering from multiple sclerosis is then contacted with the support. The positive binding of T cell receptors to the support indicates the presence of T cells specific for immunodominant MBP epitopes in the biological sample.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 1. MBP-specific T cell monoclone. a. Generation and characterization of MBP-specific T cell lines.

To generate MBP-specific T cells from peripheral blood, fresh blood samples were obtained by venipuncture and diluted with an equal volume of RPMI medium (GIBCO) . Peripheral blood mononuclear cells (PBMC) were isolated by Ficoll density gradient separation (Zhang et al., Cell. Immunol. 139, 118, 1992) . This method comprises following steps : diluted blood is overlaid on Ficoll and centrifuged at 1,800 rpm for 20 min. Subsequently the PBMC are washed three times and resuspended to a homogeneous suspension. PBMC are then plated out by limiting dilution (Zhang et al., Ann. Neurol. 32,330, 1992) at 200,000 cells, 100,000 cells and 50,000 cells per wells (60 wells for each cell concentration) in U-bottomed microwell plates, consisting of 96 wells of 200 μl content/plate) (Costar, Cambridge, USA). To each well, 100,000 autologous irradiated (8,000 radε) PBMC are added as a source of antigen-presenting cells (APC) in the presence of 40 μg /ml of human MBP.

Human MBP is extracted from the white matter of human brain tissue and purified by column chromatography (Hashim et al., J. Neurosci. Res. 16, 467, 1986) . These conditions were optimized, in a set of experiments involving more than 50 clinical blood samples, to give a maximal T cell response. Cultures were maintained in an incubator conditioned with 5% C02 and 37°C for 7 days. After 7 days, cultures were restimulated with 100,000 /well irradiated autologous PBMC pulsed with MBP. Pulsing of PBMC was carried out by incubating PBMC with 100 μg /ml of MBP at 37°C for four hours. Free MBP was washed away prior to irradiation of the cells.

Selection of MBP-specific T cell lines was performed at Day 12 and Day 14 in a proliferation assay. Each culture was split into four aliquots (approximately 10⁴ cells per aliquot) and cultured in duplicates in the presence of 10⁵ autologous PBMC pulsed or non pulsed (control) with MBP for 72 hours. 1 μCi/well of ³H-thymidine was added during the last 16 hours of cultu eand the cells were collected with the use of a cell harvester (Betaplate 1295-004, Pharmacia) . Tritiated thymidine uptake was measured in a beta scintillation counter (Betaplate 1205, Pharmacia) .

The frequency of MBP-specific T cells was calculated according to the Poisson statistics (Lefkovits et al. eds. Limiting dilution analysis of cells in the immune system. Cambridge, Cambridge University Press, 1979; Fey et al. J. Exp. Med. 158, 40, 1983) . Briefly, a culture was scored positive if its mean CPM was greater than 1,000 and if the CPM were at least three times higher than the control CPM, a frequency of positive wells was obtained at each cell concentration. Estimation of the frequency of growth- positive T cells or antigen-specific T cells was then done by applying the Poisson Formula : Fr = (u^r/r!) x e^"u, where Fr is the probability of obtaining r specific T cells in a well when the number of PBMC per well is u at a given concentration. The fraction of negative wells is given by F₀ = e^"u . When u - 1, F₀ = 0.37. Therefore, theoretically, when the average number of responding T cells per well is one, 37% of the wells will be scored as negative. Extrapolation to this point in limiting dilution gives a number of cells, the reciprocal of which represents the frequency of the antigen-specific T cells in question. MBP-specific T cells occur at an estimated frequency between IO^'7 and IO^"6 in peripheral blood lymphocytes both in patients with MS and controls (Zhang et al., Ann. Neurol. 32, 330, 1992; Ota et al.. Nature 346, 183, 1990). Culture medium used was RPMI 1640 supplemented with 10% autologous serum (heat-inactivated at 56°C for 30 min.), 2 mM L-glutamine, 50 μg/ml gentamicin, (Gibco, Life Technologies) , and 10 mM Hepes buffer (Flow Laboratories, Belgium) .

Selected MBP-specific T cell lines were plated out at 10,000 cells per well and restimulated with irradiated autologous APC pulsed with MBP. 7 days later, the cell lines were re-examined for their specific proliferation in response to MBP in a proliferation assay (described above) . An example is given in Table I to illustrate the procedure. MBP- specific T cell lines were further examined for phenotype expression and reactivity to the MBP fragments and synthetic peptides as shown in Figure 1A-1B. To define the reactivity to fragments and peptides of human MBP, 10⁴ cells of each MBP-specific T cell line were cultured with 10⁵ irradiated autologous PBMC or EBV-transformed B cells pulsed with respective peptides. To prepare antigen-pulsed APC, PBMC or B cells were incubated with 2 to 5 μg/ml of a peptide or a peptide mix for four hours and washed two times before irradiation. Specific proliferative response to a fragment or peptide was measured in a proliferation assay.

Our data have revealed that T cell responses to MBP in humans are restricted to the CD4 phenotype and directed predominantly to two immunodominant epitopes on MBP. One is located within the 84-102 region and the other resides in the 149-170 region (Reviewed in Zhang et al., Intern. Rev. Immunol. 9, 183, 1992). Reactivity to these two immunodominant epitopes accounts for more than 60% of the T cell responses to MBP (Zhang et al., Ann. Neurol. 32, 330, 1992; Ota et al. , Nature 346, 183, 1990; Pette et al. , Proc. Natl. Acad. Sci. 87, 7968, 1990).

Table I shows an example of a general scheme used to establish MBP-specific T cell lines from PBMC.

Figure 1 illustrates the reactivity pattern of a panel of MBP-specific T cell lines to three MBP fragments, spanning 1-38, 45-89 and 90-170 regions of human MBP (Figure 1A) and to synthetic peptides overlapping the 84-171 region of MBP (Figure IB) . b. Single-cell cloning of MBP-specific T cells:

It has been problematic to clone out a true MBP-specific T cell clone owing to a limited source of autologous antigen-presenting cells (APC) , a low cloning efficiency and the induction of T cell tolerance during the MBP stimulation process (LaSalle et al., J. Exp. Med. 176, 177, 1992). Therefore, cloning of MBP-specific T cell lines by repeated MBP stimulation in the presence of APC usually requires a seeding concentration of more than one cell per well. As a result, a resultant "clone" preparation is often contaminated with unwanted T cells. This contamination can be detected by the expression of TCR Vβ gene usage. A true clone usually gives rise to a single expression of TCR Vβ gene when tested with a panel of TCR Vβ gene primers by polymerase chain reaction (PCR) while multiple Vβ gene usages in a clone preparation indicates oligoclonal contamination. An example of such contamination is given in Figure 2 (panel A and panel B) , which shows oligoclonality after cloning at 3 cells per well. This oligoclonality is most likely caused by contaminating T cells present in an original T cell line preparation. This can be further confirmed by Poisson statistics (see Lefkovits et al. eds. Limiting dilution analysis of cells in the immune system. Cambridge, Cambridge University Press, 1979) . Furthermore, these MBP-specific contaminated T cell "clones" display poor growth characteristics and frequently loose their antigen specificity. It, therefore, is extremely troublesome to maintain these "clones" in a long-term culture to reach high enough amounts of cells which are required for therapeutic use.

To cope with these problems an alternative cloning procedure was developed. In this method, PHA, a potent T cell stimulating agent, is used to clone MBP-specific T cell lines at very low cell densities. MBP-specific T cells are plated out at 0.1 cell and 0.3 cell per well in the presence of irradiated autologous or allogeneic PBMC and PHA at 0.2 to 10 μg/ml. Cultures are refed with fresh culture medium containing rIL-2 (5 units /ml) every three days. At Day 14, growth-positive clones (usually 6% - 10% positive rate) are tested for their specific response to MBP, as described above. MBP-specific T cell clones derived from this cloning procedure are highly proliferative to MBP and .other T cell stimuli, including anti-CD3 antibodies (Weber et al., J. Immunol. 135, 2337, 1985), PHA, ConA and IL-2 and can be further expanded to more then 10⁷ - 10⁸ cells by alternate stimulation with MBP and PHA.

This method has many advantages over conventional cloning methods by MBP stimulation, including (1) higher cloning efficiency, (2) improved growth characteristics, which allow for a large scale expansion of the clones with PHA or MBP stimulation, (3) maintenance of MBP specificity after repeated expansions and (4) monoclonality, confirmed by a single TCR Vβ gene expression (Figure 4, panels C, D and E) .

Figure 2 represents the PCR analysis of TCR Vβ gene usage of MBP-specific T cell clones cloned by repeated MBP stimulation (panel A-B) and by PHA stimulation (panel C-D) . Panel E represents single Vβ gene usage of a typical TIL clone cloned by the PHA method. The V/3 genes of the clones were first amplified by each of 20 family-specific primers with a standard PCR technique (35 cycles) and a particular Vβ gene product was then hybridized with a specific probe in a Southern blot analysis. An amplified TCR Vβ gene product(s) is indicated, along with molecular weight markers. Cβ refers to constant β gene products.

Figure 3 represents the comparison of cloning efficiency of MBP-specific T cell lines by PHA and MBP stimulation (a representative experiment) . A MBP- specific T cell line (stimulation index 11.2) was cloned by limiting dilution at indicated cell concentrations and stimulated by MBP (left panel) or PHA (right panel) in the presence of autologous PBMC. Data are given as frequencies of growth-positive wells (open circles) and MBP-specific T cell clones (closed circles) . The frequency of MBP-specific T cells was estimated by the Poisson probability to be 1/250 by MBP cloning and 1/5 by PHA cloning. c. Vaccination procedure.

Selection of MBP-specific T cell clones for T cell vaccination is based upon two characteristics : a. The peptide reactivity to the two immunodominant epitopes on the MBP molecule or to another epitope(s) predominantly used in that particular individual. It has been well documented that T cell recognition to MBP is predominantly directed at the 84-102 region and the 149-170 region of MBP (Zhang et al., Cell. Immunol. 129, 189, 1990; Zhang et al. Ann. Neurol. 32, 330, 1992; Ota et al. Nature, 346, 183, 1990). Although the encephalitogenic epitopes in humans remain unclear, it can be extrapolated from animal studies that immunodominant determinants are likely to have encephalitogenic properties (Vandenbark et al., J. Immunol. 135, 229, 1985; Za vil et al., J. Exp. Med. 162, 2107, 1985). b. The second criterion is that the T cell clones selected must have good growth characteristics, which permit large scale expansions of the clones to a sufficient amount (3xl0₇-6 x IO⁷) for a total of at least two inoculations.

T cell clones are activated with MBP-pulsed autologous APC four days prior to inoculation and tested for common bacterial and viral contaminants (Hafler et al., Clin. Immuno. Immunopath. 62, 307, 1992) . Cells are then washed three times with sterile PBS (filtered through a filter with 0.22 μm pore size) and irradiated at 8,000 rads. For each immunization, a pool of 10⁷ - 1.5 xlO⁷ irradiated cells of at least two different MBP-specific T cell clones are prepared in 1 ml PBS as a vaccine and injected (5 x IO⁶ cells in 0.5 ml of PBS per arm) subcutaneously. Selection of this amount of cells for vaccination is calculated on the basis of an effective dose in EAE (Beraud, in Edelson ed. Antigen and clone-specific immunoregulation, Ann. NY. Acad. Sci. 636, 124, 1991). The subcutaneous route of injection is chosen as experiments performed in rats showed that subcutaneous injection is as effective as intravenous injection (I. Cohen, unpublished data) . d. In vivo induction of anti-clonotypic T cells:

Table II shows the clinical data of six patients with MS who participated in the trial and the fine specificities of the MBP-specific T cell clones used for vaccination.

Table II represents the peptide reactivity of MBP-specific T cell clones used as inoculates. MBP- specific T cell lines were generated from peripheral blood of the patients, as described above and cloned at 0.3 cell per well by limiting dilution with 10⁵ irradiated autologous feeders and PHA (2 μg /ml) . Cultures were refreshed with culture medium containing 5 units rIL-2/ml every three days. After 12 - 14 days, growing clones were examined for their reactivity to three fragments of MBP, covering 1-37, 45-89 and 90-170 regions of MBP (provided by Dr. SH Chou) and subsequently tested with 11 peptides of MBP (provided by Dr. D. Hafler) . 10⁴ cells of each clone were cultured with 10⁵ irradiated autologous APC per well, to which 10 μg ml of each fragment or 2 μg /ml of each peptide was added. Cells were cultured for 72 hours and pulsed with [3H]-thymidine during the last 16 hours of culture and harvested (Betaplate 1295) to measure tritiated thymidine uptake. The same procedure was used in other proliferation assays mentioned elsewhere in this patent application.

Experiments were designed to follow-up T cell responses to the inoculates as compared to PHA-induced autologous T blasts. PHA-induced T blasts were prepared concurrently with MBP-specific T cell clones in order to parallel the cell growth cycle. To this end, freshly isolated PBMC were cultured for four days at 10⁶ cells /ml in the presence of 2 μg /ml PHA. Cells were washed three times prior to use. As shown in Figure 4, all six patients developed a substantial proliferative response to the autologous vaccine preparation especially after the second inoculation. These responses were accompanied by a limited reactivity to the T blasts. The frequency analysis of the MBP-specific T cells revealed a progressive decline of circulating MBP- specific T cells, notably after the second inoculation. The decrease in the frequency of MBP-specific T cells was antagonistically correlated with the magnitude of the anti-clonotypic responses (Figure 4) . The frequency fell below the detectable limit of our assay in five out of six recipients at the end of the clinical trial. MBP-specific T cells in patient HM could still be detected after the third vaccination, but at a five _fold lower frequency (1.1 x IO^"7) than the pre- vaccination value. By striking contrast, the frequency of TT-specific T cells remained unchanged in all recipients while the frequency of MBP-specific T cells in two non-recipient patients (parallel controls) also remained unchanged (Figure 5) , which is compatible with a specific down-regulation of MBP-specific T cells, suggesting that these MBP-specific T cells were either eliminated or were non reactive to MBP.

Figure 4 shows the proliferative responses to the inoculates and control T cells and the changes in the frequency of MBP-specific T cells before and after each inoculation. The assays were performed before vaccination and at Day 3, Week 1, Week 2, Week 4, Week 6 and Week 8 after each inoculation. Fresh peripheral blood mononuclear cells (PBMC) were isolated and 5 x IO⁴ cells /well were cultured in triplicates with 5 x

10⁴ irradiated inoculates or autologous PHA-induced T blasts prepared concurrently for 72 hours. As a control, PBMC and irradiated inoculates or T blasts were cultured alone. Cell proliferations were measured by proliferation assays as mentioned above. Data are given as stimulation indices defined as the mean counts per minute (CPM) of PBMC plus irradiated inoculates or T blasts / the sum of CPM of PBMC cultured alone and CPM of irradiated inoculates or • T blasts cultured alone. The frequency of MBP-specific and TT-specific T cells was analyzed before vaccination and after each inoculation. PBMC were plated out at 2 x IO⁵ cells and

10⁵ cells per well for MBP stimulation (40 μg /ml MBP) or plated out at 2 xlO⁴ and 10⁴ cells per well for TT stimulation (2.5 Lf TT /ml), respectively (60 wells for each concentration) . The concentration range was predetermined to allow a sensitive detection. Cultures were then restimulated with MBP- or TT-pulsed PBMC as a source of APC and rIL-2 was added at 5 units /ml. After one week, each culture was split and tested for specific proliferation to MBP or TT in a proliferation assay. A T cell line was defined "specific" when the ratio of the CPM of wells containing MBP- or TT-pulsed APC / CPM of control wells exceeded 3 and if Δ CPM was larger than 1,000. The frequency of antigen-specific T cells was estimated by dividing the number of specific wells by the total amount of PBMC plated out.

Figure 5 represents the relationship of changes in the frequencies of T cells reactive to MBP, TT and inoculates in recipients (GE and CW) and non- recipients (AH and GC) . The frequency analysis of MBP- and TT-specific T cells is described above. To estimate the frequency of T cells responding to the inoculates, freshly isolated PBMC were plated out at 4xl0⁴ and 2 xlO⁴ cells per well and cultured with 4xl0⁴ irradiated inoculates. After 7 days, cultures were restimulated with the irradiated stimulator (vaccine) and supplemented with rIL-2 (5 units /ml). At Day 14, 50% of each culture was taken out respectively and irradiated at 8,000 rads. Cells were then split into four aliquots and added in duplicate to culture wells containing 10⁴ inoculates or TT-specific T cells and 10⁵ irradiated APC pulsed with MBP or TT in proliferation assays to measure their inhibitory effect. The inhibition was measured as 1 - (proliferation in the presence of irradiated responding T cells as inhibitor / proliferation in the absence of the inhibitor) x 100%. Cultures exerting more than 60% inhibition on the proliferation of inoculates were considered as responding cell lines. The frequency was estimated by dividing the number of responding wells by total PBMC plated out(6 xlO⁴ cells).

Based upon the observed T cell proliferative responses to the inoculates, experiments were designed to isolate responding T cells when the responses to the inoculates reached a peak level. To this end mononuclear cells were derived after the second or t_hird inoculation and were co-cultured with irradiated autologous MBP-specific T cell inoculates as stimulators. The cultures were re-challenged with the same irradiated T cell preparation. Selection of responding cell lines was based upon specific inhibition (> 70%) on proliferation of the inoculates to MBP (see Figure 5 legend) . Specific suppressor T cells were detectable in all three recipients tested with estimated frequencies of 0.2 xlO^'6 (BC) , 2.3 xlO^"6 (CW) and 5.2 xlO^'6 (GE) but not in two non-recipient control patients (Figure 5) . 24 short-term cell lines were selected from two recipients CW and GE for further characterization to define their phenotypic profile and reactivity. "Our data revealed that all the cell lines expressed the CD3 phenotype and the β T cell receptor. Twenty-two T cell lines were CD8+ and two were CD4+. The inhibition was not mediated by culture supernatants as they did not affect the proliferation of MBP- specific T cells. These inhibitory T cell lines were further examined for their functional properties and specific recognition of the autologous inoculates as compared to a tetanus toxoid (TT)-reactive clone. Figure 6A illustrates that both CD4+ (CW2F3) and CD8+ (CW1G9, GE1B3 and GE1D6) T cell lines were stimulated specifically by the autologous inoculates but not by the TT-reactive clone. They were potent inhibitors specifically for the inoculates (Figure 6B) . With the exception of the CD4+ cell line, all three CD8+ lines were found to lyse the inoculates in a standard 4-hour chromium-release assay (Figure 6C) and this antigen- specific cytotoxicity could be blocked by the addition of a monoclonal antibody to MHC class I molecules (W6/32) but not by an antibody to the class II products (Figure 6D) , indicating that the T cell recognition of the inoculates was restricted by MHC class I molecules. Similar results were obtained from seven other CD8+ cell lines. Thus, these T cell lines may be classified as anti-clonotypic T cells because of their specific recognition of a clonotypic structure on the MBP specific T-cells in the inoculates (see Lamb et al., Nature 300, 456, 1982; Mohagheghpour et al., J. Exp. Med. 164, 950, 1986; Holoshitz et al. , Science 219, 56, 1983) . It is possible that the anti-clonotypic T cells we obtained represent only a part of the T cell populations induced by the vaccination since the selection was based on their inhibitory effect. Other responding T cells may act by driving the regulation network to enhance the suppression, as typically illustrated by anti-ergotypic T cells isolated from vaccinated experimental animals (Lider et al., Science 239, 181, 1988).

Figure 6 represents the functional properties of the anti-clonotypic T cell lines. Panel A, anti- clonotypic T cell lines, tested as responders, were plated out in triplicates at 2 x 10⁴ cells /ml and cultured with 4 x IO⁴ autologous inoculates or TT- specific T cells as stimulators, which were irradiated (8,000 rads) to prevent their own proliferation. The CPM of the irradiated stimulators did not exceeded 1,200. Panel B, anti-clonotypic T cell lines were irradiated and used as inhibitors. 10⁴ cells were added in triplicates to wells containing 10⁴ cells from the inoculates or TT-specific T cells and 10⁵ APC pulsed with MBP or TT in a proliferation assay. The percentage of inhibition was calculated as specified in Figure 5. Panel C, the inoculates or TT-specific T cells were labeled with 200 μCi ⁵¹Cr for 45 min. , subsequently washed four times and used as target cells in a standard chromium-release assay. After four-hours of incubation, supernatants were harvested and the radioactivity was measured. The effector (anti- clonotypic T cells) to target (the inoculates and control T cells) ratio was eight. The maximum and spontaneous releases of chromium were determined in wells containing detergent or medium alone. The percentage of specific cytolysis was calculated as ((experimental release - spontaneous release) / (maximum release - spontaneous release)) x 100. Panel D, three anti-clonotypic clones were tested for antibody blocking in a chromium release assay. The antibodies used were either directede against class I molecules (W6/32) or against class II molecules (HB55) . AHF4.2 was a CD4+ cytotoxic T cell clone specific for MBP-pulsed target cells used as a control. Effector clones were pre incubated with indicated antibodies at 10 μg /ml for 30 min. before mixing with ⁵¹Cr-labeled target cells. The effector to target ratio was eight, e. Monitoring of clinical improvement and possible toxic effects induced by T cell vaccination

Monitoring for toxicity over the entire trial confirmed that this vaccination was safe as no side- effects were observed and no changes in the standard systematic toxicity tests were observed. There was no evidence for acute exacerbations after the vaccinations.

Administration of the vaccines induced substantial anti-clonotypic T cell responses specifically to the vaccine clones, which were accompanied with a specific depletion of circulating MBP-reactive T cells in all six recipients. These responses were marked by a boosting effect with each vaccination (Figure 1) . The in vivo depletion of MBP- reactive T cells appears to be the direct effect of anti-clonotypic T cells since the CD8+ anti-clonotypic T cell lines isolated from the vaccinated patients specifically lyse the autologous vaccine clones. The study has confirmed in a clinical setting that T cell vaccination can be used to boost clonotypic regulatory mechanisms in depleting pathologically relevant autoreactive T cells. Fig. 9 represents the anti-clonotypic T cell responses to the vaccine clones and changes in the estimated frequency of circulating MBP-reactive T cells in six patients with MS, before and after each inoculation.

The responses to the vaccine clones were determined in proliferation assays, in which peripheral blood mononuclear cells (PBMC) were cultured with irradiated vaccine clones. The proliferative responses were calculated as stimulation indices (proliferation of PBMC in the presence of vaccine clones/the sum of spontaneous proliferation of PBMC alone and residual proliferation of irradiated vaccine clones) . Data are given as mean stimulation indices of seven assays after each inoculation. The frequency of MBP-reactive T cells was estimated according to the method described in ref. 25. The frequency before vaccination is indicated on the lines, which ranges from 5.8xl0^"7 to ll.δxlO^"6 in these patients.

There are a number of issues that have emerged from the study. First, the clinical study has confirmed that clonally expanded MBP-reactive T cells in MS represent a dominant TCR repertoire and depletion of this population(s) eradicates the major responses to MBP. In this context, a question may be raised as to whether the depletion of a dominant TCR repertoire will lead to the display of a previously cryptic epitope(s) substitutive for the lost repertoire. Although MBP- reactive T cells have not been found in the vaccinated patients two years after vaccination using the whole MBP molecule as a probe, this possibility can not be ruled out as they may emerge after some time with a different label (different epitope reactivity and V gene usage) . Furthermore, the study suggests that the anticlonotypic T cells recognizing MBP-reactive T cells are pre-existing and occur at a rather low frequency in MS patients prior to vaccination. The responses are boosted by each inoculation and their frequency mounts typically to a ten-fold increase after the second and the third vaccination. Thus, it is important to further address the questions as to whether the anticlonotypic T cell responses are consistently low in MS patients and whether they are associated with hyperactivity of MBP-reactive T cells in the disease.

As for the molecular identity of the target sequence(s) that triggers the anticlonotypic T cells, at least tow variable regions have been mapped so far using a panel of CD8⁺MHC class I-restricted anti¬ clonotypic T cells isolated from three vaccinated patients (Figure 10) . One involves the CDR3 region characteristic for its unique junctional sequence of a given vaccine clone, as indicated by recognition of anti-clonotypic T cells to a target TCR sequence uniquely expressed on the immunizing T cells. The anti-clonotypic T cell clones with this recognition pattern responded specifically to the immunizing MBP- specific T cell clone but not to a total of 18 other autologous and MHC-matched allogeneic MBP-specific T cell clones not used for vaccination. The other pattern is associated with a clonotypic marker relatively conserved within the Vα region among autologous T cells. This is evident by their reactivity, in addition to the immunizing T cell clones, to other autologous and MHC-matched allogeneic MBP-specific T cells bearing the same Vα sequences. The CDR3 recognition pattern seems to be the dominant one and is highly specific for the immunizing clones. The other target sequence involved is likely to reside within the CDR2 or related regions and this recognition is less selective. In addition to the immunizing clones, the anti-clonotypic T cell lines of this recognition pattern affect autologous or MHC-matched T cells that have an unrelated specificity but bear the same Vα gene products T cell vaccination could be generalized using a peptide(s) to a category of patients whose targeted autoreactive T cells share a common TCR structural feature. A more generalized form of T cell vaccination can depend on its simplified version that takes the advantage of using synthetic peptides or related T cell membrane fractions containing a desired target sequence(s) .

The CDR2 region sequence is relatively conserved, implying that it is shared by a category of individuals. The Vα CDR2 sequences may have more limited heterogeneity as compared to its Vβ coutnerparts. Thus, to augment a CDR2-related clonotypic interaction, a library of "made-to-fit" peptides may be generated and a particular "off-shelf" peptide can be selected to attack a given CDR2 or a related sequence shared by the clonally expanded autoreactive T cells in a group of patients. In contrast, a CDR3 region sequence is known to be highly diverse from clone to clone. For a CDR3-restricted regulation, a potential use of similar strategy relies solely on the possibility that the target sequences of the CDR3 recognition pattern may display limited motifs within the V-D-J regions and these sequence motifs may constitute a common epitope(s) for clonotypic interaction. Indeed, such limited V-D-J sequence motifs have been identified among T cells specific for the 89-106 region (one of the immunodominant regions) of human MBP and these common motifs are rather consistent among 89-106 reactive T cells, irrespective of their host origins, f. Cloning of anti-clonotypic T cells.

The same procedure as described sub b) for the cloning of MBP-specific T cells was applied for the cloning of anti-clonotypic T cells. Technically anti¬ clonotypic T cell lines as described sub d) were plated out at 0.1 cell and 0.3 cell per well in the presence of irradiated autologous or allogeneic PBMC and PHA at 2 μg/ml. Cultures are refed with fresh culture medium containing rIL-2 (5 units/ml) every three days. At Day 14, growth-positive clones (usually 8% - 10% positive rate) are tested for their specific recognition and cytotoxic activity towards the inoculates. Anti¬ clonotypic T cell clones derived from this cloning procedure are highly proliferative to the irradiated inoculates and other T cell stimuli and can be further expanded to more than IO⁷ - 10⁸ cells by adding rIL-2 at each cell passage.

Table III illustrates a typical experiment in cloning of anti-clonotypic T cell lines.

2. Tumor-specific T cell monoclone. a. Generation and characterization of tumor specific lymphocytes (TSL) .

Tumors excised from patients were immediately transported from the hospital to the laboratory. They were then minced into 1-2 mm pieces and subsequently treated with an enzymatic solution containing hyaluronidase type V 0.01%, collagenase type IV 0.1% (Sigma, Vel, Belgium), DNase type I 0.002%, gentamicin 50 μg/ml and fungizone 250 ng/ml dissolved in RPMI 1640 medium (Gibco, Life technologies, Belgium) . The mixture was incubated for 2-4 hours at 37°C or overnight at room temperature. It was then filtered through a sterile coarse wire grid, washed four times with RPMI 1640 medium, and resuspended in culture medium which was RPMI 1640 supplemented with 10% fetal calf serum, 2 mM L-glutamine, 50 μg/ml gentamicin, 250 ng/ml fungizone (Gibco, Life Technologies) , and 10 mM Hepes buffer (Flow Laboratories, Belgium) . rIL-2 was added at a final concentration of 200 U/ml (Eurocetus) . 200 U/ml of lL2 obtained from Eurocetus equals to 5 U/ml obtained from Bochringer Manheim (Germany) (Zhang et al. J. Exp. Med. Vol. 179 1994) TSL were cultured in 24-well plates (Costar, ElsColab, Belgium) in 2 ml aliquots the first 4 weeks and then after dividing the aliquots in two equal parts cultured in the absence or presence of oxidized PBL (see below) in 24-well or 12- well plates.

Expansion of tumor specific lymphocytes (TSL) in vitro is hampered by several factors, including the limited amount of lymphocytes that can be obtained from tumors, unknown target antigens and a limited supply of antigen-presenting cells (APC) which are generally believed to be essential in the classical way of T cell stimulation and expansion. In approaching these difficulties, we have used surface-oxidized allogeneic PBL to stimulate the TSL periodically in the presence of rIL-2 (200 IU/ml) (Chin, Y. et al. Anticancer Res. 12, 733, 1992). TSL derived from 22 (out of 23) tumor specimens could be expanded with 20 -IO⁷ fold increases over 6 - 16 weeks, to a sufficient amount of 10⁹ -10¹¹ cells for adoptive immunotherapy. In contrast, only 2 100 fold increases were observed in six tumor specimens (out of 23) when 200 IU/ml rIL-2 was used only. The phenotypes, autologous tumor reactivity and cytolytic capability of TSL propagated with surface- oxidized stimulators were similar to those expanded in the presence of IL-2 alone. These data suggest that expanding TSL with surface-modified stimulator cells could be a useful alternative method to obtain large amounts of tumor specific cytolytic T cells for clinical immunotherapeutic use, irrespective of tumor- antigen stimulation and MHC restriction.

Oxidation of PBL was performed according to Novogrodsky and Fleischer. Briefly, irradiated allogeneic PBL (4xl0⁷-6 x IO⁷ cells/ml) from normal subjects were incubated with galactose oxidase 0.05 U/ml (Sigma) and neuraminidase 0.02 U/ml (Boehringer Mannheim, Germany) in RPMI 1640 medium for 90 min. at 37°C and shaken at 15 min. intervals to prevent formation of clumps. The cells were washed three times with RPMI 1640 containing 0.01 M galactose (Sigma) to block the residual effects of galactose oxidase. Oxidized PBL were added to TSL cultures mentioned above at a ratio of 5-10 oxidized PBL to 1 TSL. Cells were restimulated on a weekly basis with oxidized PBL in culture medium containing fresh rIL-2, and viable cell concentrations were returned to 0.5 x IO⁶ cells/ml at each passage.

TSL cell lines were then characterized as to their proliferative response to autologous and allogeneic tumor targets and their cytotoxic activity against the tumor targets.

Figure 7 shows the proliferative response of TSL lines to autologous and allogeneic tumor targets. IO⁴ cells of each TSL line were cultured in triplicate in the presence of 10⁵ irradiated PBMC and autologous or allogeneic tumor cells, respectively. Microcultures were then pulsed with 1 μCi of [³H]-thymidine (Radioche ical Center, Amersham, England) per well 4 hours prior to harvesting and thymidine uptake was measured by liquid scintillation counting.

Figure 8 represents the cytotoxic activity of the TSL lines against autologous and allogeneic tumor cells, NK-sensitive K562 cell line, and NK-resistant Daudi cell line. Target cells were labeled with 200 μCi ⁵¹Cr(Na₂Cr₃0₄, Amersham, England) for 60 min. at 37°C and washed four times with medium. Target cells were reincubated for another 30 min. and washed twice before use. 5 x 10³ labeled target cells were incubated with TSL in 96-well plates in triplicate at various effector:target ratios in a total of 200 μl volume. Supernatants were harvested with a Skatron-Titertec system after 4 hour incubation at 37°C and the radioactivity was counted in a gamma counter. The maximum release and spontaneous release of chromium were measured in wells containing target cells in the presence of detergent or medium alone. The specific release was calculated as

exp.release - spon.release

% specific lysis = x 100% max.release - spon.release

b. Single cell cloning for tumor infiltrating T cell lines specific for tumor antigens

The same cloning procedure is applicable for establishing tumor-specific TIL clones for therapeutic use. As described in 1-b, TIL lines are cloned by limiting dilution at 0.1 cell, 0.3 cell and 1 cell per well in the presence of irradiated allogeneic PBMC and 2 μg PHA/ml. Cultures are refed with fresh culture medium containing r-IL-2 (5 units/ml) every three days. At Day 14, growth-positive clones (usually 8 - 10% positive rate) are tested for their specific cytotoxic activity against autologous tumor targets in a standard chromium-release assay as described above. Specific clones derived from this cloning are highly proliferative to autologous tumor cells and to other T cell stimuli and can be further expanded to more than IO⁹ - 10¹¹ cells, required for adoptive immunotherapy, by adding rIL-2 at each cell passage. TCR Vβ gene usage of a typical TIL clone is given in Figure 2 (panel E) . 3. Foreign antigen specific T cell monoclone. a. Generation of T cell lines specific for foreign antigens

The procedure for the generation of MBP- specific T cells can be applied to other antigens as well. Tetanus Toxoid (TT) specific T cell lines were generated as described for MBP-specific T cell lines in 1-a. The concentration of Tetanus Toxoid antigen used was 2.5 Lf TT per ml. b. Single cell cloning of T cells specific for foreign antigens. Tetanus toxoid (TT) specific T cells were cloned with the procedure described in 1-b. Technically TT-specific T cells are plated out at 0.1 cell and 0.3 cells per well in the presence of autologous or allogeneic PBMC and PHA at 2 μg/ml. Cultures are refed with fresh culture medium containing r-IL-2 (5 units/ml) every three days. At Day 14, growth-positive clones (usually 8 - 10% positive rate) are tested for their specific response to Tetanus Toxoid. TT-specific T cell clones derived from this cloning are highly proliferative to Tetanus Toxoid and other T cell stimuli and can be further expanded to more than IO⁷ - IO⁹ cells by adding rIL-2 at each cell passage. This method has similar advantages over conventional cloning by TT stimulation as specified in 1-b.

The same procedures can be applied for the generation of T-cell lines and the isolation of T cell monoclones that are specific for other antigens such as allergens which are responsible for T cell mediated allergies. The expanded T-cell monoclones, specific for T-cell mediated allergies, can be used for the treatment of these allergies by applying the same vaccination procedure as specified in 1-c.

Table I Example of a typical generation of MBP-specific T cell lines from a patient with MS

experimental setup time schedule T cell line stimulation index

200,000 cells /well day O

100,000 cells /well restimulation day 7 addition of rIL-2 day 9 proliferation assay day 14 1E3 5.2

1E4 9.6

1E5 11.2

2G5 12.6

3F6 5.9

3F7 3.8 restimulation day 17 addition of rIL-2 day 19 proliferation assay day 24 1E3 27

1E4 132

1E5 74.6

2G5 43.7

3F6 4.2

3F7 120.3 single-cell cloning day 27

Table II Clinical data of the recipients with MS and fine specificity of the MBP-specific T cell clones used in the clinical trial proliferative response (CPM incorporated x 10^" )

patient age/sex diagnosis EDSS T cell clone medium alone MBP p84-102 pl43-168 pl 10-129

BC 43/M chronic 7.0 BC12 0.2±0.02 6.8±0.5 0.3±0.04 8.2±0.6 N.T progressive BC-6 0.2±0.01 5.6±0.4 0.3±0.02 0.2±0.01 3.4±0.1

IB7-E4 O.l±O.Ol 42.5±3.1 43.8±2.2 O.l±O.Ol N.T

BR 31/F relapsing 1.0 BR- 1 1.2±0.2 28.7±2.2 1.6±0.2 22.1±2.8 N.T remitting BR-3 0.8±0.09 16.6±1.8 1.1±0.15 18.4±2.5 N.T

IG7 1.7±0.1 52.3±4.8 1 .3±0.1 47.4±5.2 N.T

RM 47/M relapsing 4.5 ID5 0.8±0.08 45.8±5.9 1.2±0.14 38.7±4.6 N.T remitting HM- 1 1.4±0.12 78.5±7.9 1 .8±0.2 82.2±7.2 N.T

CW 46/M chronic 7.5 CW-5 O. l±O.O l 17.8±1.6 0.2±0.01 0.4±0.03 0.2±0.02 progressive CW-10 O. l±O.Ol 5.4±0.6 O.l±O.Ol 7.8±0.8 N.T

1 E4 O. l±O.O l 37.6±4.8 0.3±0.02 27.3±2.4 N.T

NF 46/F primary 4.5 C I O 0.7±0.04 32.8±2.6 1.1±0.02 1.4±0.06 l . l±O. l progressive IB3 . l . l±O.l 13.1±1.2 0.7±0.05 1.3±0.08 1.8±0.2

GE 26/F relapsing 3.0 GE-2 1.4±0.1 20.1±1.8 1 1.2±0.8 l .l±O. l N.T remitting GE-3 l .ό±O. l 42.2±2.3 23.6±2.1 2.2±0.1 N.T

GE-4 2.8±0.3 37.0±3.2 24.8±2.2 1.9±0.2 N.T

TABLE III Cloning of anti-clonotypic T cell lines by the method of the invention

T cell line growth-positive specific clones (% specific cytolysis) / total culture wells / growth-positive

1F4 8/180 3/8 1F4-4 (64%)

1F4-5 (70%)

1F4-7 (68%)

1G9 5/180 1/5 1G9-1 (45%)

1B8 14/180 2/14 1B8-5 (82%)

1B8-10 (86%)

2C7 4/180 1/4 2C7-4 (48%)

1D6 14/180 6/14 1D6-1 (91%)

1D6-3 (89%)

1D6-9 (100%)

1D6-11 (77%)

1D6-12 (69%)

1D6-14 (94%)

1B2 8/180 5/8 1B2-2 (78%)

1B2-3 (82%)

1B2-5 (74%)

1B2-7 (66%)

1B2-8 (54%)

1B3 7/180 4/7 1B3-D4 (56%)

1B3-E6 (43%)

1B3-F8 (42%)

1E7 6/180 3/6 1E7-G6 (48%)

1E7-F4 (52%)

1E7-F10 (43%)

negative clones < 2-8% Table IV Evidence for clonal expansion of MBP-reactive T cells in patients with MS

subject No. of clones peptide reactivity DR restriction Vβ usage V-D-J DNA sequence pattern

MS-1 5 84-102(3/5) DR2(5/5) 7.2 (3/5) sequence pattern 1 * (3/5) only MBP (1 /5) 7.1 (1/5) sequence pattern 2 ( 1/5) only MBP ( 1 /5) 7.1 ( 1/5) sequence pattern 3 (1/5)

MS-2 7 84-102 (7/7) DR2 (7/7) 2.1 (6/7) sequence pattern 1 * (5/7) 21 (1/7) sequence pattern 2 52/7)

MS-3 15 84-102 ( 15/15) DR2 (15/15) 17.1 (5/15) sequence pattern 1* (5/15) 17.1(6/15) sequence pattern 2* (6/15) *^* 6.1 (3/15) sequence pattern 3 (3/15) 4.3 (1/15) sequence pattern 4 (1/15)

MS-4 3 143-168 (3/3) DR2 (3/3) 13.1 (3/3) a single sequence pattern* (3/3)

MS-5 4 84-102 (4/4) DR7 (4/4) 17.1 (4/4) a single sequence pattern* (4/4)

34 independent MBP-specific T cell clones isolated from finve MS patmients were analyzed for their Vβ gene ussage and th V-D-J junctional DNA sequences by PCR techniques. The number of clones positively tested for the indicated parameters is given in parentheses. A predominant V-D-J sequence pattern(s) is indicated by the asterisk.

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Claims

1. A population of human T cell monoclones which is highly proliferative in the presence of an antigen to which said human T cells are specific and which is characterized by its full biological purity in that it remains free of contaminating cells at all stages of subsequent culture development.

2. Human T cell monoclone population according to claim 1 characterized in that it gives rise to a single TCR V gene expression.

3. Human T cell monoclone population according to any one of the preceding claims characterized in that it possesses a unique TCR V-D-J DNA sequence.

4. Human T cell monoclone population according to any one of the preceding claims characterized in that it comprises cells of either the CD4 or the CD8 phenotype.

5. Human T cell monoclone population according to any one of the preceding claims characterized in that the antigen in the presence of which said population is proliferative is a tumor cell or an immunogenic portion thereof.

6. Human T cell monoclone population according to any one of claims 1 to 5, characterized in that the antigen in the presence of which said population is proliferative is an auto-antigen.

7. Human T cell monoclone population according to claim 6, characterized in that the auto- antigen is a Myelin antigen or an immunogenic portion thereof.

8. Human T cell monoclone population according to claim 7 characterized in that the Myelin antigen is selected from the group consisting of the Myelin Basic Protein (MBP) , the Proteolipid Protein (PLP) , the Myelin-Associated-Glycoprotein (MAG) , the Myelin-Oligodendrocyte-Glycoprotein (MOG) and/or a mixture thereof.

9. Human T cell monoclone population according to claim 8, characterized in that the Mielin antigen is an epitope of the 84-102 region or the 149-170 region of the amino acid sequence of Myelin Basic Protein.

10. Human T cell monoclone population according to any one of claims 1 to 4 characterized in that the antigen in the presence of which said population is proliferative is a foreign antigen.

11. Human T cell monoclone according to claim 10 characterized in that said foreign antigen is a Tetanus Toxoid antigen.

12. Human T cell monoclone population according to any one of claims 1 to 4 characterized in that the antigen in the presence of which said population is proliferative is an allergen that is mediating the allergy through T cells.

13. Human T cell monoclone directed to the human T cell monoclone according to any of the preceding claims.

14. Human T cell monoclone according to claim 13, directed to a Myelin Basic Protein-specific human T cell monoclone.

15. Human T cell monoclone according to claim 13, directed to a human T cell monoclone specific for the epitope of the 84-102 region or ghe 149-170 region of the amino acid sequence of the Myelin Basic Protein.

16. A method for the production of a population of human T cell monoclones which is highly proliferative in the presence of the antigen to which said human T cells are specific and/or any other T cell stimulating agent, and which is characterized by its full biological purity in that it remains free of contaminating cells at all stages of subsequent culture development, said method comprising: (1) providing a human T cell line responsive to said antigen;

(2) single cell cloning said T cell line and stimulating the resulting T cell clone with a T cell stimulating agent in the presence of autologous or allogeneic feeder cells to produce populations of human T cell monoclones; and

(3) selecting the monoclone population having the desired TCR-specific characteristics.

17. A method according to claim 16 characterized in that said human T cell line is taken from peripheral blood lymphocytes (PBL)

18. A method according to claim 16 or 17 characterized in that T cell stimulating agent is selected from the group consisting of lectines, preferably PHA and/or ConA, lymphokines, preferably Interleukin-2 (IL-2) and/or a recombinant IL-2(r-IL2) mitogenic antibodies against CD3 and other cell surface molecules and/or a mixture thereof.

19. Process according to claim 18, characterized in that the T cell stimulating agent is PHA.

20. A homogeneous population of T cell receptors from human T cell monoclones according to any one of claims 1 to 12 or the antigen-specific portion thereof and/or a mixture of selected populations or portions.

21. A therapeutic agent for the treatment of autoimmune diseases, said therapeutic agent comprising an effective amount of a population or a mixture of selected populations of T cell monoclones according to any one of claims 1 to 10.

22. A therapeutic agent for the treatment of a T cell mediated allergy, said therapeutic agent comprising an effective amount of a population or a mixture of selected populations of T cell monoclones according to any one of claims 1 to 4 and 12.

23. A therapeutic agent for the treatment of infections and cancer, said therapeutic agent comprising an effective amount of a population or a mixture of selected populations of T cell monoclone according to any one of claims 1 to 6.

24. A vaccine composition for conferring upon humans active immunity against autoimmune diseases, said vaccine composition comprising an effective amount of a homogeneous population of T cell receptors according to claims 1 to 12 from human T cell monoclones or the antigen-specific portion thereof.

25. A vaccine composition for conferring upon humans active immunity against autoimmune diseases, said vaccine composition comprising a population or a mixture of selected populations of T cell receptors obtained from the population of human T cell monoclones according to claim 1 to 12.

26. A method for the treatment of a patient suffering from a condition associated with one or more antigens specific to said condition and obtainable from a biological sample of said patient, said method comprising: vaccinating said patient with or adoptively transferring to said patient an amount of a human T cell monoclone population sufficient to generate the appropriate immune response to at least partially alleviate said condition, whereby said human T cell monoclone population is responsive to said one or more antigens and has a full biological purity in that it remains free of contaminating cells at all steps of culture development.

27. A method according to claim 26 wherein said condition is associated with one or more antigens specific to an infection.

28. A method according to claim 26 wherein said condition is associated with one or more antigens specific to an autoimmune disease.

29. A method according to claim 26 wherein said condition is associated with one or more antigens specific to a T cell mediated allergy.

30. A method according to claim 26 wherein said condition is associated with one or more antigens specific to a cancer.

31. A kit for the identification of those human T cell monoclones which are highly proliferative to an antigen of the type which may be held responsible of a particularly diagnosed disease and for the subsequent preparation of a population of said identified human T cell monoclones, said kit comprising:

(1) an antigen specific to the diagnosed disease in sufficient amounts to generate cell lines responsive to said antigen from a biological sample;

(2) means for plating said human T cell lines at very low cell densities; and

(3) a T cell stimulating agent for growing said low density human T cells.

32. A kit according to claim 31, further comprising protocols and essential reagents for the characterization of said T cell monoclones.

33. A kit according to claim 31 or 32 wherein said antigen is Myelin Basic Protein.

34. A kit according to claim 31 OR 32 wherein said antigen is an epitope of the 84-102 region or the 149-170 region of the amino acid sequence of Myelin Basic Protein.

35. A kit according to claim 31 or 32 wherein said antigen is selected from the group consisting of Collagen type II, Heat shock Protein or Superantigens.

36. A kit according to claim 31 or 32 wherein said antigen is a Proteolipid Protein.

37. A kit according to claim 31 or 32 wherein said antigen is Gluta ic acid decarboxylase.

38. A kit according to claim 31 or 32 wherein said antigen is selected from the group consisting of Nickel, poison Ivy and rubber.

39. Use of one or more selected population(s) of antigenic human T cell monoclones according to claims 1 to 2 for the treatment of infectious diseases, autoimmune diseases, T cell mediated allergies or cancer.

40. Use of a homogeneous population or a mixture of selected homogeneous populations of T cell receptors from human T cell monoclones according to any one of claims 1 to 12 or the antigen-specific portion thereof for the treatment of infectious diseases, autoimmune diseases, T cell mediated allergies or cancer.

41. Use of a population or a mixture of selected populations of human T cell monoclones according to any one of claims 1 to 12, for the production of a pharmaceutical composition intended for the treatment of infectious diseases, autoimmune diseases, T cell mediated allergies or cancer.

42. A diagnostic kit comprising an appropriate solid support for immobilizing a biological sample containing a specific T cell responsive to an antigen, means for at least immobilizing said specific T cell on said support and an antibody to a T cell monoclone receptor that binds the antigen associated with or specific to the condition to be diagnosed.

43. A diagnostic kit according to claim 42, wherein said antibody is a monoclonal antibody.