Fig. 2.

Inflammatory signalling triggered by the interaction of diesel exhaust particles and inhaled allergens. Exposure to low doses of allergens does not generate an immune response. However, this same exposure combined with exposure to diesel exhaust particles induces Th2-response-related IL-4, 5 or 13 expression and Th17-response-related IL-17A, 17F or cytokine CCL20 expression. Exposure to high doses of inhaled allergens generates a typical Th2 response. CCL20: chemokine ligand 20; DEP: diesel exhaust particles; IL: interleukin.