IL-4 and IL-6 production of bone marrow-derived mast cells is enhanced by treatment with environmental pollutants.

To examine the potential effects of environmental pollutants on the production of cytokines in mast cells, mouse bone marrow-derived mast cells (BMMC) were cultured at various concentrations of diesel exhaust particulates (DEP) or formaldeyhde. Proliferation of BMMC at 0.8, 2 and 4 microg/ml of DEP and 0.5 and 1 microg/ml of formaldehyde did not differ significantly from that of the controls (0 microg/ml) after 72 h culture, with the exception of a significant decrease in proliferation at 5 microg/ml of formaldehyde. Treatment with DEP or formaldehyde alone did not induce interleukin-4 (IL-4) or IL-6 production by BMMC. IL-4 and IL-6 production in BMMC stimulated with A23187 was higher in BMMC treated with low concentrations of DEP than in controls, but no increase was seen in BMMC treated with high DEP. IL-4 and IL-6 production in A23187-stimulated BMMC was significantly increased at 0.5 and 1 microg/ml formaldehyde but decreased at 5 microg/ml formaldehyde. After pretreatment with low DEP or formaldehyde alone for 24h, IL-4 production of BMMC stimulated with A23187 was lower in BMMC treated with low DEP or formaldehyde than in controls. Antigen-induced IL-4 production significantly increased in BMMC treated with 0.4 or 0.8 microg/ml DEP or 0.5 microg/ml formaldehyde, but antigen-induced IL-6 production in BMMC did not increase at low DEP or formaldehyde. Although the enhancement of IL-4 production of BMMC stimulated with A23187 plus DEP was not completely inhibited by 5x10(-4) M 2-mercaptoethanol (2-ME), treatment with 10(-7) M dexamethasone inhibited further IL-4 production. Cytokine production of mast cells is thus shown here for the first time to be modulated by treatment with DEP or formaldehyde. Environmental pollutants such as DEP and formaldehyde may thus affect the immune response via the modulation of cytokine production in mast cells.