Biologic and Biochemical Characterization of a Macrophage-Derived Growth Factor for Rat Lung Fibroblasts

Abstract

Growth factors such as platelet-derived growth factor (PDGF) and the transforming growth factors (TGF) have diverse biologic activities that influence physiologic development, wound healing and neoplastic transformation of cells. Macrophages have been shown to be important in the process of inflammation and repair through secretion of soluble mediators that can alter the growth of other cells. 1 Leibovich SJ Ross R The role of the macrophage in wound repair: a study with hydrocortisone and anti-macrophage serum. Am J Pathol. 1975; 78: 71-100 PubMed Google Scholar Studies in this laboratory with an animal inhalation model have shown that macrophages are attracted to sites of particle deposition by a complement-dependent mechanism and that these cells are temporally associated with a developing interstitial fibrotic lesion. 2 Warheit DB George G Hill LH Snyderman R Brody AR Inhaled asbestos activates a complement dependent chemoattractant for macrophages. Lab Invest. 1985; 52: 505-514 PubMed Google Scholar , 3 Warheit DB Hill LH George G Brody AR Time course of chemotactic factor generation and the corresponding macrophage response to asbestos inhalation. Am Rev Respir Dis. 1986; 134: 128-133 PubMed Google Scholar In the present study, we show that rat alveolar macrophages (AM) activated by particulates in vitro secrete a heat-stable competence factor for rat lung fibroblasts (RLF) with immunologic similarities to a sis oncogene-predicted synthetic peptide.