IMMUNOLOGICAL RESPONSE AGAINST ALLOGENEIC CHONDROCYTES TRANSPLANTED INTO JOINT SURFACE-DEFECTS IN RATS

Rat chondrocytes isolated from the articular-epiphyseal cartilage comp lex were transplanted into defects prepared in articular cartilage and subchondral bone. Transplants were taken for examination after 3 and 8 mk. Cartilage formed by syngeneic chondrocytes did not evoke formati on of infiltrations. Contrary to that, in the vicinity of cartilage pr oduced by allogeneic chondrocytes numerous infiltrating cells were pre sent and cartilage resorption could be observed. Cyclosporine-A (CsA) treatment of recipients of allogeneic chondrocytes only partially supp ressed accumulation of infiltrating cells and matrix resorption, Antic hondrocyte immune response of chondrocyte graft recipients was studied by evaluation of spleen mononuclear cells (SMC) stimulation in mixed splenocyte-chondrocyte cultures and by evaluation of antichondrocyte c ytotoxic antibodies. No difference in stimulation of SMC from intact r ats by syngeneic and allogeneic chondrocytes was observed. Stimulation by allogeneic chondrocytes was slightly but significantly higher in r ecipients of syngeneic grafts. SMC of allogenic chondrocyte recipients were strongly stimulated by allogeneic chondrocytes. This response wa s absent in recipients treated with CsA. Spontaneous antichondrocyte c ytotoxic antibody activity was detected in intact rats and in recipien ts of syngeneic grafts. In recipients of allogeneic chondrocytes the a ntibody response against allogeneic chondrocytes was raised but was st atistically not significant offing to the considerable variation in th e level of spontaneously occurring antichondrocyte antibodies. (C) 199 7 Elsevier Science Inc.