Abstract

Using a modification of an in vitro model of fibrogenesis, lung connective tissue antibodies have been shown to stimulate macrophages to release a collagen stimulating factor acting on fibroblast target cells. This stimulation was measured by increased hydroxyproline production from fibroblasts that had reached stationary growth phase. In subcytotoxic amounts, this antibody had no such effect directly on fibroblasts. These findings further illustrate the value of studying fibrogenesis by the in vitro method.