The object of this project is the study of mechanisms regulating connective tissue formation and destruction. The areas of reasearch are: (1) normal regulation of macrophage collagenase and connective tissue degradation in an immune inflammatory lesion, (2) the role of macrophages in collagen production and the relationship of these syntheses to wound healing and inflammation, (3) effect of lymphocyte and macrophage products on fibroblast proliferation and collagen synthesis, and (4) the production of collagenase by fibroblasts from patients with familial osteolysis.