Involvement of interleukin-1-like factor(s) in type II collagen-induced arthritis in mice

To explore the role of interleukins in development of arthritis, we induced collagen-induced arthritis in mice and examined interleukin activities in the inflamed joints. Arthritis developed in 90% of mice 4-5 weeks after primary immunization with type II collagen. Joint extracts from mice with collagen-induced arthritis contained high levels of interleukin 1 (IL-1)-like activity but not interleukin 2 (IL-2) or interleukin 4 (IL-4) activity. IL-1-like activities in the lesions were correlated with development of arthritis assessed by joint swelling and erythema. These results suggest that IL-1-like factor(s) may participate in the etiopathogenesis of collagen-induced arthritis in mice.