Matrix antigens in allografts. The humoral response.

The roles of matrix antigens, link proteins (LP) and proteoglycan monomer (PG) were investigated with regard to the late rejection of joint allografts. Antisera to these antigens were produced in the rabbit. With the use of immunofluorescent techniques, these antigens can be detected in host synovium as early as six weeks after transplantation. At about 12 weeks, antibody reaction against LP and PG was detected in the recipient synovium and circulation. After transplantation there is apparently a slow release of antigen from the cartilage matrix that is concentrated within the synoviun. An immune response occurs in the tissue which subsequently becomes transformed into a pannus and ultimately destroys the allograft. Whether the humoral response observed is primarily responsible for allograft rejection has not been determined. LP and PG could evoke a cytotoxic response that is more significant. Histocompatibility antigens could be primarily responsible for allograft rejection and the humoral response to LP and PG may be a secondary phenomenon.