DIESEL EXHAUST PARTICLES ENHANCE ANTIGEN-INDUCED AIRWAY INFLAMMATION AND LOCAL CYTOKINE EXPRESSION IN MICE

Previous experimental studies have suggested that nasal instillation o f diesel exhaust particles (DEP) can enhance nasal IgE response and cy tokine production. However, there is no experimental evidence for the relation of DEP to allergic asthma. We investigated the effects of DEP inoculated intra tratracheally on antigen-induced airway inflammation , local expression of cytokine proteins, and antigen-specific immunogl obulin production in mice, DEP aggravated ovalbumin-induced airway inf lammation characterized by infiltration of eosinophils and lymphocytes and an increase in goblet cells in bronchial epithelium. DEP with ant igen markedly increased interleukin-5 (IL-5) protein levers in lung ti ssue and bronchoalveolar ravage supernatants compared with either anti gen or. DEP alone. The combination of DEP and antigen induced signific ant increases in local expression of IL-4, granulocyte macrophage-colo ny stimulating Factor (GM-CSF), and IL-2 whereas expression of interfe ron-gamma war not affected, In addition, DEP exhibited adjuvant activi ty for the antigen-specific production of IgG and IgE, These results p rovide the first experimental evidence that DEP can enhance the manife stations of allergic asthma. The enhancement may be mediated mainly by the increased local expression of IL-5, and also by the modulated exp ression of IL-4 GM-CSF, and IL-2.