Interleukin 1 production and accessory cell function of rat alveolar macrophages exposed to mineral dust particles.

Immunostimulatory effects of respirable mineral dust particles on alveolar macrophages (AM) and T lymphocytes were tested in vitro. When rat AM were incubated with fibrogenic silica and asbestos particles, a significant interleukin 1 (IL-1) activity was generated into the culture supernatants, whereas neither AM alone nor AM incubated with non-fibrogenic titanium dioxide (TiO2) particles, however, produced a detectable amount of IL-1. Interleukin 2 (IL-2) activity, as tested with IL-2-dependent CTLL-2 assays, was not detectable from all of these cultures. It was also revealed that concanavalin A-induced proliferation of T lymphocytes was enhanced in autologous AM and nylon wool-passed spleen cell co-cultures incubated only with fibrogenic particles, but not with non-fibrogenic particles. Higher IL-1 activity was detected only from co-cultures exposed to fibrogenic particles, whereas IL-2 activity was almost similar among these co-cultures. These results indicate the differences in immunostimulatory effects on pulmonary macrophages and T lymphocytes among a variety of mineral dust particles.