S-100 protein in human articular cartilage

We studied the immunohistochemical distribution of the alpha and beta subunits of S-100 protein in human articular cartilage by the Avidin-Biotin Complex method using monoclonal antibodies against each subunit. Immunostaining for both subunits was detected in chondrocytes in superficial, intermediate, and deep zones of normal articular cartilage. In the matrix, only the superficial zone was stained positively. In arthrotic joints, we detected intense immunostaining in clustered chondrocytes in the hypercellular area, and weak or no immunostaining in isolated chondrocytes in the hypocellular area of articular cartilage.