Effects of chrysotile asbestos on mononuclear cells in vitro

Chrysotile asbestos (400 micrograms/ml) was not found to be cytotoxic towards human blood lymphocytes in culture over a 72 h period, although there was indirect evidence of cytoxicity towards plastic adherent mononuclear cells (PAM). There was significant suppression of 3H-thymidine incorporation into cells cultured with phytohaemagglutinin (PHA) in the presence of fibres. It was found even when chrysotile was added 24 h after PHA. No suppression was found for chrysotile-treated PAM-depleted cultures in comparison to control cultures. Antibody-dependent cell-mediated cytotoxicty (ADCC) was inhibited by the presence of chrysotile, and appeared to be due to prevention of contact between antibody-coated target cells and effector cells.