induction of apoptosis in human peripheral blood lymphocytes with silicate in vitro *
Several environmental factors have been reported to induce autoimmune diseases ; e.g. progressive systemic sclerosis in patients with silicosis. I have investigated whether the incidence of autoimmune diseases is influenced by silicate, and previously reported the existence of superantigenicity of silicate to human lymphocytes in vitro . In this study, using the TUNEL method, we recognized the induction of apoptosis in human lymphocytes with silicate in vitro . Peripheral blood mononuclear cells (PBMC) were separated from the heparinized blood of healthy volunteers and cultured with chrysotile. Then the surface markers of PBMC and apoptosis were analyzed flow cytometrically. As a result, I found that CD4+ cells especially were activated by chrysotile and induced to apoptosis. Fas molecules seemed to be involved in the induction of apoptosis, because the expression of Fas on the cell surface of lymphocytes decreased according to the incidence of apoptosis. Therefore it might be speculated that the induction of apoptosis in human peripheral blood lymphocytes after stimulation with silicate plays a role in the elimination of clones, which are excessively activated. (Accepted on April 2 , 1997) Kawasaki Igakkaishi 23(1) : 19―26, 1997
