Type II collagen‐specific human T cell lines established from healthy donors

Four type II collagen‐specific T cell lines established from the peripheral blood of a healthy donor were studied in detail. These CD4+ T cell lines with an α/β T cell receptor proliferated in response to native and denatured human and chicken type II collagen and human type I collagen, but not to human type IV collagen or other potentially arthritogenic antigens. The T cell response showed typical dose response characteristics, peaked between 30 and 48 h, was major histocompatibility complex class II restricted and not due to a mitogenic effect. Type II collagen‐reactive T cells could hardly be detected in freshly isolated peripheral blood mononuclear cells from healthy donors, as revealed by limiting dilution analysis (frequency < 1/100000). By prestimulation in bulk cultures for 10 days, type II collagen‐reactive T cells could be approximately 1000‐fold enriched. However, in these limiting dilution cultures, collagen‐reactive T cells could only be observed in a narrow window of cell concentrations, suggesting that type II collagen‐reactive T cells may be controlled by suppressive mechanisms in healthy persons.