TYPE-XI COLLAGEN-INDUCED ARTHRITIS IN THE LEWIS RAT - CHARACTERIZATION OF CELLULAR AND HUMORAL IMMUNE-RESPONSES TO NATIVE TYPE-XI, TYPE-V, AND TYPE-II COLLAGEN AND CONSTITUENT ALPHA-CHAINS

Autoimmune arthritis can be induced in rats by immunization with carti lage-specific types II and XI collagen. Type XI collagen is composed o f alpha 1(XI), alpha 2(XI), and alpha 3(XI) chains, in which alpha 3(X I) is essentially identical to alpha 1(II) of type II, and alpha 1(XI) and alpha 2(XI) are similar to alpha 1(V) and alpha 2(V) of type V co llagen. To characterize the immune response to type XI collagen, Lewis rats were injected with bovine type XI collagen, and the cellular and humoral responses were compared with those of rats injected with type s V and II collagen. Arthritis, Ige deposits in cartilage, and joint d estruction were seen in rats immunized with types XI and II collagen. Type XI elicited strong cellular responses to rat types XI, V, and II; conversely, types II and V collagen elicited strong responses to rat type XI. Antitype XI Abs reacted with rat type XI, moderately with rat type V, but poorly with rat type II. Direct and inhibition ELISA show ed that cross-reactions between types XI and V collagen resulted from recognition of determinants shared by their respective alpha 2(XI) and alpha 1(V) chains. Abs eluted from joints of rats immunized with type XI collagen, however, reacted only with native rat type XI collagen. These data demonstrate that type XI collagen induces diverse populatio ns of Abs differing in collagen-type specificity, and suggest that onl y those Abs to native rat type XI collagen are central to the pathogen esis of type XI collagen-induced arthritis.