Diesel Exhaust Particles and the Induction of Macrophage Activation and Dysfunction

Diesel exhaust particles (DEP) are an important component of air particulate matter, generated from the incomplete combustion of fossil fuel in diesel engines. Several epidemiological and experimental data have shown the ability of DEP to induce oxidative stress and pro-inflammatory response as mechanisms in macrophage activation and dysfunction. Macrophages are very important to immunity and immune response due to their ability to phagocyte microbes and parasites. They also respond to toxic chemicals, such as DEP, in the environment and studies have shown that their functions may be impaired by their exposure to DEP. For instance, the ultrafine particles (UFP) of DEP are capable of penetrating deep into the lungs and getting deposited in the alveolar component, where they can mitigate against the phagocytosis function of the alveolar macrophages. In this review, data linking DEP exposure to macrophage activation and dysfunction are addressed together with the various mechanisms involved in these DEP-induced effects.