Immunogenicity of xenogeneic cartilage matrix components in a rabbit model

Purified xenogeneic cartilage matrix components, including proteoglycan subunits, chondroitin 4 sulfate, and chondroitin 6 sulfate, were inoculated into the knee joint of rabbits, and local as well as systemic responses were evaluated. proteoglycan was associated with synovial hyperplasia and infiltrates of eosinophils and lymphocytes and with rising titers of antiproteoglycan antibodies in a tanned sheep rbc hemagglutination assay over a six-week period of weekly intra-articular injections and observations. Chondroitin sulfates failed to evoke detectable changes in the joint or serum. Immunogenicity of cartilage matrix components may play a role in allogeneic and xenogeneic osteochondral grafts, and it is also possible that autogenous matrix immunogens exist and contribute to progression of degenerative joint disease. The immunogenicity of allogeneic and autogenous cartilage matrix components remains undefined.