p205 and RA: T cell reactivity with a RF-epitope

Journal/Book: Z Rheumatol 1999; 58 Suppl. 1: I/34 (F 17). 1999;

Abstract: 1Dept. Rheumatol & Clin Immunol Charité Univ. Hospital Berlin; 2Rheumaklinik Eisenmoorbad Bad Liebenwerda; 3Inst. Laboratoriemedisin Rikshospitalet Oslo Synovial fluid (SF) stimulates T cells from RA patients. The p205 antigen was purified from SF as Ihe major proliferative factor. p205 contains an 11 aminoacid (aa) stretch identical to an IgG sequence in the CH2 region which is known to be targeted by rheumatoid factors (RFs). The aim of this study was to analyze the significance of p205 reactive T cells for the pathogenesis of RA. p205 was purified biochemically and applied to T cell proliferation assays. Cells were pulsed with 3H thymidine. Kinetic studies revealed highest p205 specific T cell proliferation on day 3 indicative of in vivo-activated T cells. T cells in all cases tested responded better when isolated from SF than from peripheral blood. p205 specific T cells were determined in 70 % of RA patients (sensitivity) and in 4 % of patients with other rheumatic diseases (specificity: 96 %). Proliferation assays pulsed with FITC conjugated bromodesoxyuridine were stained for T and B cell markers and analyzed by FACS. Proliferating p205 specific cells comprised of both CD4+ and CD8+ single positive T cells at frequencies of 2.6 % respectively. Frequencies obtained for PHA reactive cells were 10-fold higher. B cells did not proliferate. Proliferation assays performed in the presence of blocking anti-HLA-DR antibodies inhibited p205 specific proliferation. These data clearly demonstrate that p205 specific T cell proliferation is a nominal but not a mitogenic or superantigenic antigen response. ... le

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