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Experimental and spontaneous autoimmune disease in animals can effectively be prevented and treated by application of pathogenic autoreactive T cells in an attenuated form. This approach has become known as T cell vaccination. T cell vaccination exploits specifically the ability of the immune system to regulate its autoreactive T cells by mechanisms of network control. The success of T cell vaccination in a variety of rodent animal models has raised hopes for its use as an effective and specific therapy in human autoimmune disease. The aim of this study was to induce an anti-T cell response by T cell vaccination in humans and primates as a pre-clinical study into the feasibility and toxicity of T cell vaccination. Using bulk cultures of T cells from the peripheral blood or an inflamed joint, it was possible to induce a T cell response specific for the injected vaccine and its activation state both in rhesus monkeys and in two patients with active rheumatoid arthritis. In one of the patients there was already a spontaneous T cell response against a mitogen driven T cell line from the peripheral blood, but not against a control T cell line specific for tetanus toxoid, suggesting that regulatory T cell networks are operative in patients with autoimmune disease. Significant clinical effects or side-effects were not observed. The results suggest that T cell vaccination in humans is feasible and non-toxic. It is likely to influence an already ongoing regulatory process. Conditions for making T cell vaccination an effective therapy need still to be worked out by further studies both in primates and in less complex human immune processes.

Synovial fluid (SF) mononuclear cells from a patient with Chlamydia trachomatis induced acute Reiter's disease were directly by limiting dilution in a representative protocol using phytohemagglutinin in the cloning medium. Out of 76 alpha beta-TCR+ CD4+ T lymphocyte clones, 7 were shown to specifically recognize C. trachomatis in a proliferation assay. The antigen recognition of these clones was HLA-DP restricted. Unexpectedly, 2 HLA-DR restricted clones showed a proliferative response to Yersinia enterocolitica O3, though the patient had no history of yersinia infection. The high frequency of SF derived T cells with specificity for species-specific chlamydial antigens and the limited diversity of HLA class II restriction of these clones may indicate an oligoclonal synovial T cell response to persistent intraarticular chlamydia.

Humoral and cellular immune reactions to heat-shock proteins have been implicated in the pathogenesis of arthritis. Heat-shock proteins occur in bacteria as well as all eukaryotes and have been highly conserved during evolution. Cross-reactivity between bacterial and human heat-shock proteins induced at the site of inflammation may underlie the pathogenesis of some forms of arthritis. In order to test this hypothesis, we raised and cloned a Yersinia-specific T cell line from the synovial fluid lymphocytes of a patient with Yersinia-induced reactive arthritis. From this line we obtained a CD4+ T cell clone that proliferated in response to Yersinia antigens and both to the mycobacterial and the human 65-kDa heat-shock protein. This T cell clone also proliferated in response to autologous heat-stressed antigen-presenting cells as well as to synovial fluid mononuclear cells from the inflamed joint, thus showing true autoreactivity against endogenously synthetized self-antigen. These results demonstrate the induction of an autoimmune T cell response by a natural bacterial infection and support the important role of heat-shock proteins in the pathogenesis of immune-mediated arthritis.

Autoantibodies to the human hepatic asialoglycoprotein receptor have been found in nearly 50% of the sera of patients with autoimmune chronic active hepatitis and in 15% of patients with primary biliary cirrhosis. In this study we demonstrate that the human hepatic asialoglycoprotein receptor is also a target antigen for T cell-mediated immune responses. Peripheral blood lymphocytes of 37% (7 of 19) of patients with autoimmune chronic active hepatitis and 33% (2 of 6) of patients with primary biliary cirrhosis showed a proliferative response to highly purified human hepatic asialoglycoprotein receptor, whereas no proliferation was found with peripheral blood lymphocytes of patients with chronic viral hepatitis (0 of 13) and healthy blood donors (0 of 4). Moreover, we isolated T-cell clones from liver biopsy samples of two patients with autoimmune chronic active hepatitis and two patients with peripheral blood lymphocytes. Between 2.8% and 14.3% of these clones showed a specific proliferative response to purified human hepatic asialoglycoprotein receptor. The response was restricted to autologous antigen-presenting cells and could be blocked by monoclonal antibodies against human leukocyte antigen-DR molecules. The response of T cells to the human hepatic asialoglycoprotein receptor did not require the lectinlike activity of the asialoglycoprotein receptor. Thus the human hepatic asialoglycoprotein receptor could be identified as a major target antigen of humoral and cellular immune reactions in autoimmune-mediated liver diseases.

From a patient with reactive arthritis following Salmonella typhimurium enteritis, synovial fluid T-lymphocytes were cloned and expanded in vitro. Seven out of 74 clones showed a marked proliferative response to antigens of heat-killed Salmonella typhimurium with autologous T-cell-depleted peripheral blood mononuclear cells as antigen-presenting cells. The Salmonella-reactive clones were of the CD4+ phenotype, antigen-induced proliferation could be inhibited by a monoclonal antibody to HLA class II. One clone recognized both Salmonella and Campylobacter jejuni antigens in the proliferation assay. The multiclonality of Salmonella-reactive synovial fluid T-cells indicates that the microorganisms have been present, at least transiently, within the affected joint and thus recruited specific T-lymphocytes that might initiate synovitis.

From synovial fluids of two patients with reactive arthritis following Yersinia enterocolitica infection, T lymphocyte clones were obtained that showed proliferative responses to Y. enterocolitica. The responses required autologous T-cell-depleted peripheral blood mononuclear cells as antigen presenting cells. Three clones were studied in detail; two of them showed a marked and specific response to Yersinia antigens alone, the other one recognized both Yersinia and Salmonella typhimurium antigens. The antigen-specific proliferation of the clones could be completely blocked by monoclonal antibodies to HLA-DR. These experiments show that synovial T lymphocytes presumably involved in the in situ immune response to microbial antigens triggering reactive arthritis can be cloned directly from the site of inflammation.