Effect of antithymocyte serum on collagen arthritis in rats: Evidence that T cells are involved in its pathogenesis

Abstract

To assess the role of T cells in collagen arthritis, a heterologous T cell-specific antiserum (ATS) was administered intraperitoneally to female Wistar-Furth rats. ATS treatment on Day −1, 1, 3, and 5 and immunization with native chick type II collagen on Day 0 resulted in a decreased incidence of arthritis (5 of 19, 26%) compared to immunized rats given either nonimmune heterologous serum on these days (20 of 25, 80%) or ATS injected on Day 5, 7, 9, and 11 (17 of 20, 85%) (P < 0.001 for both comparisons). The early-ATS protocol also was associated with a delayed onset and reduced disease severity in the few rats in this group that did develop arthritis. Both delayed-type hypersensitivity (DTH) and serum IgG antibody titers to native type II collagen, measured on Day 10, were decreased significantly (P < 0.002) in rats administered ATS beginning on Day −1 compared to the other two groups. These data suggest that T cells contribute to the inception of collagen arthritis and that their critical function occurs within the first 5 days after immunization.