Immunomodulatory effects of mineral dust. I. Effects of intraperitoneal dust inoculation on splenic lymphocyte function and humoral immune responses in vivo.

Syngeneic PVG rats and C57BL6 mice were inoculated with liquid suspensions of UICC chrysotile A asbestos, DQ12 quartz or the inert particulate TiO2. Rats received 10 mg and mice received 2.5 mg dust intraperitoneally on day 0. Injection of the pathogenic dusts asbestos and quartz was associated with a significant reduction in mitogenic response to PHA and Con A detected in splenocytes removed from animals 14 days after inoculation. Injection of TiO2 had no significant effect on splenocyte mitogenesis. Pretreatment of C57BL6 mice with asbestos intraperitoneally also impaired subsequent production of antibody to the protein antigen KLH. These data show that intraperitoneal injection of chrysotile A asbestos and DQ12 quartz had a marked effect on generalized T lymphocyte function. An additional immunomodulatory effect of asbestos injection was shown in C57BL6 mice where in vivo humoral immune responses were suppressed.