The role of cartilage minor collagens in inducing arthritis

Arthritogenic properties of native types IX, XI, and II collagen were investigated in female Wistar rats. Immunization with native type-XI or -II collagen led to the arthritic reaction in 60% of investigated rats. After boosting, a distinct increase in anticollagen antibodies was observed followed by temperature rise (swelling and redness of affected joints). At the end of the experiment (after 7 weeks) subchondral bone destruction was detectable upon x-ray examination. Histological observation of the affected knee and ankle joints showed progressive destruction of the articular cartilage and subchondral bone accompanied by proliferative synovitis with extensive formation of fibrous tissue found in joints of rats immunized with native type-XI collagen. Immune response to collagen types (determined by ELISA) reached its peak between the 14th and the 21st day. From the acute stage to the chronic stage a decrease of serum anticollagen antibodies was observed to remain constant. Rats immunized with native type IX and denatured type XI collagen did not develop arthritis.