EXPRESSION OF ICAM-1 ON ISOLATED HUMAN NASAL, AURICULAR AND COSTAL CHONDROCYTES

Expression of intercellular adhesion molecule-1 (ICAM-1) on targets ha s been reported to be a relevant factor for leukocyte migration, adhes ion and function. Because stimulated chondrocytes have been shown to e xpress molecules of immunological import (like HLA class II antigens) and because rejected or resorbed cartilage grafts used in the field of ENT arc often characterized by adjacent infiltrating leukocytes, the presence of ICAM-1 on human nasal, auricular and costal cartilage was investigated. For this study, cartilage tissue sections and chondrocyt es in suspension as well as cultured chondrocytes were prepared. Speci fic monoclonal antibodies (mAb) were used for immunocyto- and immunohi stochemical Alkaline-Phosphatase-anti-Alkaline-Phosphatase staining (A PAAP staining) as well as for flow cytometry analysis. ICAM-1 on healt hy cartilage tissue sections was not found. On the other hand, both ch ondrocytes freed from matrix and cultured chondrocytes showed strongly positive staining patterns for ICAM-1. This result was obtained for c hondrocytes from nasal, auricular as well as costal cartilage. This ob served expression of ICAM-1 on chondrocytes with defective extracellul ar matrix demonstrates that cartilage cells are able to synthesize ICA M-1 without any paracrine stimulus from non-chondrocyte cells. It sugg ests that ICAM-1 plays a role in processes where tissue damage leads t o the exposure of chondrocyte surfaces. Therefore, ICAM-1 expression o n chondrocytes may also be a factor in destructive cartilage graft res orption.