Induction of the imbalance of helper T-cell functions in mice exposed to diesel exhaust

Administration of diesel exhaust particles (DEP) increases antigen-specific IgE production and IgE-secreting cells, and induces Th2-type cytokine prof iles in the airway in mice and humans. To determine the early effects of di esel exhaust (DE) inhalation on the cytokine production profile, BALB/c mic e were exposed to 0 (controls) and 1.0 mg/m(3) DE inhalation for 4 weeks. I ntraperitoneal sensitization with ovalbumin (OVA) was conducted immediately before DE inhalation. Mice were treated with anti-CD4 or anti-CD8 mAb 1 da y before and after the sensitization. On day 21, these mice were boosted wi th OVA and blood; bronchoalveolar lavage (BAL) fluid, and spleens were coll ected on day 28. In BAL fluid, both TNF alpha and IL-10 production in DE-ex posed and control mice remained basically the same. IL-6 production in the anti-CD4 treatment group of DE-exposed mice, however, significantly increas ed compared with that of the controls. In vitro antigen-stimulated interleu kin-4 (IL-4) and -1Y (IL-10) production in spleen cells of exposed mice wer e not affected by low-dose DE inhalation. In vitro interferon (IFN)-gamma p roduction in the anti-CD4 treated group of exposed mice decreased markedly. Although anti-OVA IgE production in the plasma of sham-treated mice expose d to DE was the same level as for controls, anti-CD4 mAb treatment in DE-ex posed mice significantly reduced IgE production compared to controls. In an ti-OVA IgG1 production, anti-CD 1 or anti-CD8 mAb treatment in DE-exposed g roups also significantly reduced. Anti-OVA IgG2a production was reduced by treatment with anti-CD4, mAb, but increased by anti-CD8 mAb treatment in DE -exposed mice. Low dose DE inhalation is thus shown to adversely affect the cytokine and antibody production in mice by altering CD4(+) and CD8(+) T-c ell functions. (C) 2001 Elsevier Science B.V. All rights reserved.