IL-4 production in mediastinal lymph node cells in mice intratracheally instilled with diesel exhaust particulates and antigen.

To clarify the relationship between air pollutants and IgE antibody production, interleukin 4 (IL-4) production was investigated in BALB/c mice intratracheally injected with diesel exhaust particulates (DEP) mixed with antigen (Ovalbumin (OA) or Japanese Cedar Pollen (JCP)). BALB/c mice were injected with DEP plus OA or OA alone three times with a 3-week interval. After the last instillation, proliferative response and lymphokine-producing activity of mediastinal lymph node cells (LNC) were examined in vitro. Proliferative response to OA in mediastinal LNC from mice injected with DEP plus OA was enhanced 4-17 times of that from control mice. IL-4-producing activity by OA stimulation also enhanced in mediastinal LNC from mice injected with DEP plus OA. A significantly larger amount of anti-OA IgE antibody was detected in sera from DEP- and OA-injected mice compared with those from control mice. The levels of IL-4, estimated by JCP antigen in mediastinal LNC, from mice injected with DEP plus JCP were two-fold higher than those from mice injected with JCP alone. These results suggest that intratracheal instillation of DEP affects antigen-specific IgE antibody responses via local T-cell activation, especially enhanced IL-4 production.