WO1990014068A2

WO1990014068A2 - Anti-ergotypic t cells for the treatment or prevention of autoimmune diseases and methods of use thereof

Info

Publication number: WO1990014068A2
Application number: PCT/US1990/002407
Authority: WO
Inventors: Irun Robert Cohen; Ansgar W. Lohse
Original assignee: Irun Robert Cohen; Lohse Ansgar W
Priority date: 1989-05-02
Filing date: 1990-04-30
Publication date: 1990-11-29
Also published as: EP0427850A4; CA2032138A1; EP0427850A1; WO1990014068A3; JPH04500689A; IL94270A0

Abstract

Autoimmune diseases can be treated by administering T cells which are specific to a T cell receptor which is present on activated T cells but which is not present on non-activated T cells and which T cells are non-specific for the T cell receptor which is specific for the target protein of the autoimmune disease being treated. Such a T cell receptor is referred to as an ergotope as it is a marker of activation. Autoimmune diseases can also be treated by administering ergotypic T cells, fragments or proteins which include or comprise an ergotope. Such ergotypic T cells, fragments and proteins will serve to raise T cells which are specific to an ergotope in vivo and will thus attack the natural ergotopes on the autoimmune T cells.

Description

ANTI-ERGOTYPIC T CELLS FOR THE TREATMENT OR PREVENTION OF AUTOIMMUNE DISEASES AND METHODS OF USE THEREOF

Field of the Invention

The present invention relates to the prevention or treatment of autoimmune diseases and more particularly to compositions which are themselves anti-ergotypic or which can induce an anti-ergotypic response in vivo in order to attack all activated autoimmune T cells.

Background of the Invention Autoimmune disorders occur when the immune system attacks normal healthy tissue. Autoimmune disease, which may be crippling or fatal, can strike any tissue or organ. Its victims are often in the prime of life. The list of autoimmune diseases include multiple sclerosis, in which the tissue attacked is myelin (a substance that sheathes nerves in the central nervous system) ; myasthenia gravis, in which the target is a receptor molecule for the important neurotransmitter acetylcholine; rheumatoid arthritis, whose target is the peripheral joints; type I (juvenile) diabetes ellitus, in which the cells producing insulin are destroyed; and systemic lupus erythematosis, in which DNA, blood vessels, skin and kidneys are attacked. In all of these diseases the immunological response is strong and well focused; it is, however, directed at some essential component of the body.

TUTE SHEET Lymphocytes are the cells that mediate recogni¬ tion in the immune system. The immune system includes two such classes of cells, which are called T lymphocytes and B lymphocytes. Both types arise from stem cells in the bone marrow. The stem cells, however, lack the receptors that enable B and T cells to recognize specific molecules as targets for immune attack. Such immune receptors appear as the multipotential stem cells mature. As a result of the process of maturation, each B or T cell ultimately comes to have many copies of one immune recep¬ tor on its surface and therefore is able to recognize only one other molecule. Any molecule so recognized is called an antigen.

The process of recognition does not require the whole antigen, but only a small piece known as an epitope. If the molecule to be recognized is a polymer, such as a protein or a sugar chain, the epitope frequently consists of as few as from 4 to 6 of its thousands of monomeric subunits (amino acids in proteins, sugar units in sugar chains) . The shape and electric charge of each epitope are such that it will best fit a particular receptor. When an epitope finds its complementary receptor, they form a reversible association that generates a signal in the T or B cell. Not only can the lymphocyte receptors recognize epitopes of antigens but receptors can themselves be

SUBSTITUTE SHEET recognized by other receptors on lymphocytes or anti¬ bodies. Thus, a receptor can also be an antigen. The original specificity of the receptor is referred to as its idiotype, and the specificity of the receptor's receptor is called the anti-idiotype. The set of idiotypic recep¬ tors and anti-idiotypic receptors is believed to create a self-recognizing network which establishes an equilibrium that regulates the behavior of the immune system.

It has been experimentally determined that T cell clones which are specific for the target protein of an autoimmune disease will initiate such a disease upon administration. Such idiotypic T cells will attack the target protein and thus cause symptoms of the autoimmune disease. It is further known that if such idiotypic T cells are treated in a manner so as to make them aviru- lent, such as by subjecting them to gamma radiation or by subjecting them to pressure treatment, such cells can serve as a vaccine which will cause animals inoculated therewith to acquire permanent resistance to the disease which is otherwise induced by such T cells. It is appar¬ ent that such vaccination causes anti-idiotypic T lympho¬ cytes to be raised which will then protect against the action of idiotypic T lymphocytes which might otherwise be raised when the animal is subjected to a protein which mimics the target protein of the autoimmune disease. It is further known that the potency of the vaccine can be considerably enhanced by aggregating the receptors of the

SUBSTITUTE SHEET T lymphocytes into a mass. This may be accomplished either physically (through hydrostatic pressure) or chemi¬ cally (through agents that cross-link cell surface recep¬ tors) . Apparently, aggregating the receptors makes them more potent in generating anti-idiotypic lymphocytes.

The vaccine also serves as a form of therapy. Rats receiving cross-linked T lymphocytes taken from other sick rats quickly underwent permanent remission of their autoimmune disease. However, several observations have suggested that immunity to T cell receptors might not be the only protective element induced by T cell vaccination. First¬ ly, T cells were found to be efficient vaccines only after they had been activated by incubation with a specific antigen or a T cell mitogen before injection. For exam¬ ple, it is known that experimental autoimmune encephalomy- elitis (EAE) could be induced in laboratory animals by inoculation with basic protein (BP) a component of myelin in the central nervous system. The immunity to basic protein is manifested by paralysis (often fatal) and inflammation in the region of the brain and spinal cord where the nerve fibers are sheathed in myelin. EAE is considered to be the best laboratory model of multiple sclerosis. Activated anti-BP T cells which have been rendered avirulent are effective in the treatment of EAE. However, as few as 10⁴ activated anti-BP T cells were more effective than 5xl0⁷ idiotype positive anti-BP T cells that had not been activated (Naparstek et al, Eur. J. Immunol.. 13, 418 (1983)). Therefore, some change in T cells associated with activation appears to be important in the induction of T cell vaccination; the presence of the idiotype alone is insufficient.

Furthermore, in unreported experiments in the laboratory of the present inventors there have been ob¬ served, in addition to the high degree of disease specific protection mediated by T cell vaccination, a mild degree of non-specific protection. Lewis rats were vaccinated against EAE using either activated Zla or activated A2b T cell clones. Zla recognizes the immunologically dominant epitope present in the 68-88 amino acid sequence of BP. This clone can either produce EAE or vaccinate rats against EAE, depending upon treatment of the cells and the number of cells administered. In contrast to Zla, clone A2b recognizes a 9 amino acid sequence in the 65 kDa heat- shock protein of Mycobacterium tuberculosis. A2b was found to cause arthritis in irradiated Lewis rats or, when suitably treated, to induce resistance to adjuvant arthri¬ tis. Thus, each clone recognizes a different epitope and is associated with a different autoimmune disease. When unvaccinated control rats are challenged with Zla, all of the rats died of EAE. However, if the rats had been previously vaccinated with the specific anti-BP T clone, they become markedly resistant and developed almost no clinical disease. Rats which were vaccinated with clone

S^UBST/TUT_E ^SHEET A2b and then challenged with Zla cells acquired clinical EAE. However, the vaccination with clone A2b did prevent lethal EAE; none of the A2b treated rats died. Thus, non¬ specific vaccination using A2b produced significant resis- tance, albeit a resistance that was not as effective as that obtained with clone Zla.

In view of these observations it was theorized that other mediators of resistance to autoimmune disease exist other than the anti-target antigen idiotypic T cells.

Summary of the Invention Accordingly, it is an object of the present invention to identify the mediators of resistance to EAE induced by vaccination with T cells that do not recognize the BP antigen.

It is a further object of the present invention to develop T cells, T cell fragments and/or proteins which can induce a response which will non-specifically treat any autoimmune disease.

It is a further object of the present invention to produce T cells which will non-specifically attack any activated T cell which is causing an autoimmune disease. It is yet another object of the present inven- tion to provide processes for preventing and treating autoimmune diseases using such T cells, T cell fragments or proteins.

HEET Autoimmune diseases are caused by T cells ex¬ pressing two attributes: receptors for the specific self- antigen, which identify the target tissue, and a state of functional activation, which is a prerequisite for attack. Autoimmune diseases can be controlled by T cells that recognize not the idiotype of the autoimmune T cells, but a marker of their state of activation. These T cells, which are termed anti-ergotypic cells (ergos meaning activation) , can be induced by vaccinating rats with activated cells of syngeneic T cell clones lacking recep¬ tors for any particular target antigen. In contrast to anti-idiotypic T cells, the anti-ergotypic T cells respond to activated T cells in general, without regard for the idiotypic specificities.

Brief Description of the Drawing The Figure is a graph showing specific and non¬ specific protection against EAE following T cell vaccination.

Detailed Description of Preferred Embodiments

The following experiments illustrate the exis¬ tence of an ergotope on T cells which only appears after the T cell has been activated against a specific antigen. These experiments further establish that such activated T cells against self target proteins, which T cells cause the effects of autoimmune diseases, can be controlled by anti-ergotypic T cells which will recognize the ergotope

SUBSTITUTESHEET on any activated T cell regardless of its idiotypic specificity.

Experiment 1: Clones Zla and A2b derived from female Lewis rats, were antigen activated (10 μg/ml guinea pig BP for Zla and lOμg/ml KL_ tuberculosis for A2b) for 72 hours. The activated cells were washed and treated with 0.3% glutaraldehyde for 15 ins. at room temperature, and then washed 3 times in 50 ml VS. To vaccinate against EAE, 2xl0⁷ glutaraldehyde treated cells were injected subcu- taneously into 8 week old female Lewis rats and this vaccination was repeated twice at weekly intervals. Ten days after the last inoculation, these animals and naive control animals were challenged by intravenous injection of 5xl0⁶ activated Zla cells. EAE was assessed clini¬ cally on the basis of the following scale: 1 = tail paralysis; 2 = hind leg weakness; 3 = hind leg paralysis; 4 = paralysis of all limbs; 5 = dead. Figure 1 shows the results of this experiment. It can seen from Figure 1 that following challenge the unvaccinated control rats all died of EAE, while the rats vaccinated with the specific anti-Zla clone were markedly resistant and developed almost no clinical disease. Vaccination with clone A2b did not prevent clinical EAE, but it did prevent lethal

SUBSTITUTESHEET EAE; none of the A2b treated rats died. Thus, non¬ specific vaccination using activated A2b induced signifi¬ cant resistance, albeit a resistance that was not as effective as that obtained by vaccination with clone Zla.

Experiment 2:

Lewis rats were vaccinated with 3 weekly injec¬ tions of 2xl0⁷ antigen-activated, glutaraldehyde treated D9 cells as described in experiment 1. D9 is a subclone of Dla which induces optimal resistance to EAE. Delayed type hypersensitivity (DTH) reaction to either non- activated or activated cells of clones D9 or A2b was then assayed. DTH reactions are a convenient in vivo measure of T cell reactivity to antigens or idiotypes (see

Holoshitz et al "Arthritis Induced in Rats by Cloned T Lymphocytes Respond to Mycobacteria but not to Collagen- Type II", J. Clin. Invest.. 73, 211-215 (1984)). DTH was elicited by injecting into the pinna 3x10^s irradiated (2500R) cells in 50 μl PBS. Activated cells were taken after 72 hours of antigen stimulation. Activation was assessed microscopically and confirmed by ³H-thymidine incorporation. Non-activated cells (also known as resting cells) had been kept in IL-2 containing medium without antigen for at least 5 days. DTH reaction was measured by determining the amount of ear swelling after 48 hours using an isotonic caliper. The results of this experiment are shown in Table 1. TABLE 1

It can be seen from Table 1 that when non- activated T cell clones were used to elicit the DTH reac¬ tion, the DTH response appeared to be clonotypically specific; the response to resting D9 was significantly higher than the response to resting A2b. In contrast, the response was not clonotypically specific when activated T clones where used to elicit DTH; the difference between activated D9 and activated A2b was not particularly sig- nificant. It should further be noted from Table 1 that the naive (non-vaccinated) rats responded more strongly to the activated clones than they did to the non-activated clones and that the response to the activated clones was enhanced following T cell vaccination. These results suggest that rats vaccinated with activated T cell clones may develop responses to activation markers (ergotopes) as well as to clone specific markers. This response against activated T cells is called anti-ergotypic.

SUBSTITUTE SHEET Experiment 3:

This experiment was designed to establish that anti-ergotypic activity can be induced. Rats were in- jected with activated T cell clones A2b or D9, with mito- gen activated syngeneic spleen cells, or with a strong immunogen, M. tuberculosis (MT) .

Clones A2b and D9 were activated for 72 hours by incubation with their respective antigen (M. tuberculosis and myelin basic protein, lOμg/ml) in the presence of irradiated (2500R) autologous thymocytes. Spleen cells were stimulated for 48 hours by concanavalin A (1.25μg/ml Con A). All cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 1% autologous rat serum, lmM glutamine, 5x10"⁵ M 2-mercaptoethanol and antibiotics. Activated cells were enriched by Ficoll gradient centrifugatio . After washing, 2.5xl0⁶ living activated cells were injected into each hind footpad of 8- 12 week old female Lewis rats and the popliteal lymph nodes (PLN) were removed on day 7. The lymph node cells were suspended in the above medium and placed in U-shaped 96-well microtiter plates at a concentration of 2x 10⁵ cells/well. Stimulator cells were irradiated with 3000R and added at 2xl0⁴ cells/well. Non-activated cells had been kept in antigen-free medium for at least 5 days following antigen stimulation. This medium was supple¬ mented with 10% (v/v) supernatant of Con A stimulated

E SHE! splenocytes__.as a source of IL-2 and 10% heat inactivated horse serum.

To distinguish whether the stimulatory effect was due to a structural or a secreted component of acti- vated cells, there was added either freeze killed stimula¬ tor cells or medium conditioned by stimulator cells without cells. Activated cells were killed by repeated shock freezing and thawing. Cell death was confirmed by trypan blue staining. Supernatant of activated irradiated D9 cells was obtained by culturing those cells at 10⁶/ml for 48 hours. The supernatant was added at 1:1 (v/v) to the proliferation wells. To further cultures, 10% IL-2 containing supernatant from Con A activated living spleno- cytes was added. The results are shown in Table 2.

TABLE 2

Proliferative Response (cpm) of Primed Popliteal Lymph Node (PLN) Cells against

Autologous Activated T-Lymphocytes

C

I )

π

ND = not determined

The proliferative response of T cells to antigens is a measure of the specificity of the particu¬ lar T cells. It is known that the cells which recognize a particular antigen when cultured in the presence of that antigen will be stimulated to proliferate. It can be seen from Table 2 that lymph node cells from naive rats showed only a background proliferative response to irradiated syngeneic D9 cells and to spleen cells, activated or not. Thus, lymph nodes cells from naive rats do not contain T cells which are specific to any of the idiotopes or receptors of the stimulator cells. Previous administration to the rats of T clones A2b or D9, Con A activated spleen cells or MT antigen leads to an increase in the background prolifer- ation of the popliteal lymph node cells measured in the absence of added stimulator cells. The addition of non- activated stimulator cells, either D9 or spleen cells, leads to only a modest increase in the proliferative response above the spontaneous background. However, the addition of activated stimulator cells triggers a marked response. The rats that had been vaccinated with activated A2b, D9 or spleen cells showed a 4 to 8 fold increase in proliferation compared to that induced by the non-activated stimulator cells. The responses of the lymph node cells from the rats primed with MT anti¬ gen were relatively weaker but were still significantly higher than the background stimulation obtained either

SUBSTITUTE SHEET without stimulator cells or with non-activated stimula¬ tor cells.

Thus, anti-ergotypic responsiveness can be produced by priming rats with activated T cells or with MT antigen. Moreover, the induction of an anti- ergotypic response by MT antigen in vivo argues that the phenomenon cannot be explained by a response to some artificial modification occurring in cultured cells. The last three columns of Table 2 show the responses to membranes obtained from frozen and thawed D9 cells, to culture medium obtained from activated D9 cells, and to culture medium from Con A activated spleen cells known to contain IL-2. It can be seen that neither the supernatants of the irradiated activated D9 or spleen cells could stimulate anti-ergotypic cells but the D9 cell membranes did. Thus, anti-ergotypic cells can be stimulated by factors produced by activated T- cells or by their structural components. Furthermore, it is apparent that the anti-ergotypic cells responded to a membrane component of activated cells and not to some extracellular lymphokine.

Experiment 4:

This experiment establishes the ability of anti-ergotypic T cells to regulate immune reactions in vivo. Adoptively transferred EAE was induced by injecting 3xl0⁶ BP-activated D9 cells intravenously. Active EAE was induced by injecting 25 μg of myelin basic protein in CFA into the hind footpads. The rats were challenged on the day of treatment to measure their susceptibility to EAE, either adoptive or active. In the adoptively transferred rats 5xl0⁶ anti-ergotypic or control (A2b) T cells were administered intraperito- neally. In active EAE a second injection of 5xl0⁶ anti-ergotypic cells was done 3 days later. The inci¬ dence and clinical severity of EAE was measured as described in Experiment 1. The results are shown in Table 3.

The anti-ergotypic cells were generated as follows: naive rats were injected with 2.5xl0⁶ acti¬ vated A2b cells into each hind footpad. Popliteal lymph node cells were removed 7 days later and restimulated in vitro (5xl0⁶ cells/ml) with Con A activated irradiated (3000R) syngeneic splenocytes (5xl0⁵ cells/ml) . After 72 hours the cells were harvested, enriched by Ficoll gradient and washed.

_SUBSTITUTE SHEET TABLE 3

It can be seen from Table 3 that the Lewis rats that were challenged with D9 T cells without being treated with anti-ergotypic T cells developed severe EAE (groups 1 and 2) . In contrast, the rats that were treated with anti-ergotypic T cells were completely resistant to adoptive EAE (group 3) . Thus, intra- peritoneal administration of preformed anti-ergotypic T cells suppresses the transfer of EAE by intravenous D9 T cells. The anti-ergotypic cells also suppressed the transfer of EAE when mixed directly with the D9 BP cells (not shown) . As shown in Table 3, group 2, administration of clone A2b at the time of challenge with anti-BP clone D9 did not protect rats against EAE. However, repeated administration of clone A2b over several weeks before EAE challenge did induce some resistance (see experiment 1) . Thus, activated A2b cells are not directly anti- ergotypic, but activated A2b cells, similar to other activated T cells, can induce a protective anti- ergotypic response.

Table 3, group 5, shows that intraperitoneal inoculation of anti-ergotypic T cells led to a mild but significant suppression of active EAE.

Experiment 5:

This experiment establishes that anti- ergotypic T cells are present in human patients. Synov- ial aspirates from two patients with rheumatoid arthri- tis were centrifuged in a standard manner to isolate the cellular fraction of the synovial exudate. 2xl0⁵ (patient 1) or 10⁵ (patient 2) of these responding cells were incubated for five days in microtiter wells with irradiated (4000R) stimulator cells 5xl0⁴ (patient 1) or 2xl0⁴ (patient 2) in standard culture medium con¬ taining 5% autologous serum. The stimulator cells were peripheral blood mononuclear cells that had or had not been activated by incubation for 48 hours with the lymphocyte mitogen PHA (1 μg/ml) . Resting cells were used after 12 days at rest in medium containing IL-2 without PHA. After five days, incorporation of triti- ated thyamine was measured as an indication of the

SUBSTITUTE SHEET response of the synovial fluid T lymphocytes to the stimulator cells. The results are shown in Table 4.

T RT.Tϋ 4

Anti-Ergotypic Response in Synovial Fluid T Cells of Patients with Rheumatoid Arthritis

It can be seen from Table 4 that humans with rheumatoid arthritis have synovial fluid T cells that proliferate in a way that shows them to be anti- ergotypic; that is, the T cells respond to activated T cells but not to resting T cells. Also, the T cell response is not restricted to self-MHC stimulator T cells; similar to the murine-anti-ergotypic response, it also includes activated allogeneic T cells.

Experiment 6:

This experiment establishes that the CD2 receptor is associated with the ergotypic response.

Activated target cells were preincubated with a variety of monoclonal antibodies each specific to a particular T cell receptor. Many of the monoclonal antibodies used in this experiment are disclosed in Clark et al, J. Exp. Med. , 167:1861-1872 (1988). After such preincubation, the activated target cells were tested for anti- ergotypic response. The results are shown in Table 5.

TABLE 5

Inhibition of Anti-Ergotypic Response by Preincubation with Antibodies Specific to Various T Cell Receptors

Preincubating antibody Percent inhibition of anti-ergotypic response OX-34 (αCD2) 80.3 OX-54 (αCD2) 71.6 OX-55 (αCD2) 82.1 ART-65 (αIL2R) 0 W3-25 (αCD4) 0 OX-8 (αCD8) 0

OX-6 (αMHC II) 0 OX-18 (αMHC I) 0

As the anti-ergotypic response was inhibited by preincubation with anti-CD2 monoclonal antibodies, it is apparent that the ergotope is associated with the CD2 region. However, there may be other ergotope molecules activated during activation. It is known that several types of stimulating agents can lead to a state of activation in T cells. When the term "activation" is used throughout the present specification and claims, it is intended to refer to that state of a T cell in which

^SU^BST^ITUTE ^SHEET it expresses several or all of the following attributes as the result of contact with a stimulating agent: a. Synthesis and replication of DNA; b. Blast transformation and cell division; c. Secretion of lymphokines such as IL-2, interferon gamma, etc.; d. Expression of IL-2 receptor or other markers; e. Ability to carry out immunological reac- tions such as providing help for B cells in antibody production, mediation of delayed type hypersensitivity or cyto- toxicity; and f. Expression of heparanase and other enzymes.

Known types of stimulating agents which lead to T cell activation include:

1. Specific antigen presented to the T cell receptor via MHC molecules on an antigen presenting cell;

2. T cell itogens such as PHA (phytohemag- glutinin) or Con A (Concanavalin A) ;

3. Antibodies to the CD-3 molecule;

4. Antibodies to the CD-2 molecule; 5. Antibodies to the CD-28 molecule; and

6. The natural ligands of CD-2 or CD-28. It is thus possible that there is more than one T cell receptor which serves as a marker of the state of acti¬ vation and therefore are ergotypic according to the definition presented herein. Any such ergotypic recep¬ tor can be used as the ergotope in accordance with the present invention.

In order to treat autoimmune diseases, compo¬ sitions can be administered which either directly attack activated T cells of the patient or which induce the production of anti-ergotypic T cells which then attack the activated T cells. Once the existence of ergotopes (activation markers) is known, those of ordinary skill in the art can identify the specific structure thereof by means of routine experimentation and techniques, even if such techniques may require substantial time and effort to complete. All of the techniques necessary to isolate and sequence the specific ergotypic receptor are available to those of ordinary skill in this art and the present invention is not directed to such techniques, per se. The present invention is directed to the dis¬ covery that such an epitope exists on all autoimmune T cells and that such T cells can be controlled, or at least the control of such T cells can be aided, by means of anti-ergotypic T cells. Accordingly, the present invention is not intended to be limited to the particular anti-ergotypic T cells disclosed in the above experiments. It is

SUBSTITUTE ^SHEET comprehended that autologous anti-ergotypic T cells removed from autoimmune disease patients can be made to proliferate by culturing them in the presence of the ergotypic antigen. It is known that even if such cells are in a small minority, the presence of a particular antigen will stimulate those cells specific for that antigen to proliferate at the expense of the other lymphocytes. This is essentially a clonal selection in tissue culture. Such cultured T lymphocyte cells, which are greatly enhanced in their anti-ergotypic content, can optionally be further purified by known filtration techniques and then reinjected into the patient. Such anti-ergotypic T cells will then attack the activated T cells which are attacking the target protein and causing the symptoms of the autoimmune disease.

To produce a vaccine which will produce anti- ergotypic T cells in vivo, only the ergotypic receptor itself need be injected; active T cells need not be used. Thus, while injection of whole ergotypic T cells is comprehended for this purpose, it would be preferred to inject membrane fragments containing the ergotypic receptor or the ergotypic receptor protein itself or even just the active region of such a protein. Any of these will be capable of inducing an anti-ergotypic response which will then serve to treat or prevent any type of autoimmune disease.

E^T While the invention is described above in relation to certain specific embodiments, it will be understood that many variations are possible, and that alternative materials and reagents can be used without departing from the invention. In some cases such varia¬ tions and substitutions may require some experimenta¬ tion, but such will only involve routine testing.

The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and therefore such adaptations and modifications are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phrase¬ ology and terminology employed herein is for the purpose of description and not of limitation.

^SUB^STITU ^τεSHEET

Claims

We claim:

1. A process for the treatment of an auto¬ immune disease comprising administering anti-ergotypic T cells which are specific to a T cell receptor which is present on activated T cells but which is not present on non-activated T cells and which anti-ergotypic T cells are non-specific for the T cell receptor which is specific for the target protein of the auto-immune disease being treated.

2. A process in accordance with claim 1, wherein said anti-ergotypic T cells are autologous T cells originating with the individual being treated.

3. A process for the treatment of an auto¬ immune disease comprising administering ergotypic T cells, fragments or proteins, which ergotypic T cells, fragments or proteins contain or comprise an epitope which is present on activated T cells but which is not present on non-activated T cells and do not contain or comprise an epitope which is complementary to the target protein of the auto-immune disease being treated, said T cells, fragments or proteins being capable of raising T cells specific to the epitope thereof in vivo.

4. A T cell fragment or protein containing or comprising an epitope which is present on activated T cells but which is not present on non-activated T cells, wherein said epitope is the only immunologically active epitope on said fragment or protein.

E SHEET