Effects of instillation of fly ash in the lung: physiochemical properties and immune responses

In this study, we examined physiochemical properties of fly ash and aluminum silicate and investigated the effects of these compounds on IgE antibody production and macrophage response in the lung. Fly ash was round in shape, and aluminum silicate was indefinite in shape with respirable size. Both compounds consisted of alumina and silica as the main elements with respirable size. Enhanced IgE and IgG antiovalbumin (OA) antibody production was observed in mice first instilled intratracheally with the aluminum compounds and then given OA aerosol exposure. Histopathologic observations after instillation of fly ash and aluminum silicate showed that a large number of macrophages had ingested the compounds. However, the amount of free compound and the distribution of macrophages were different in mice given fly ash from those given aluminum silicate. These data indicate that particles of fly ash and aluminum silicate instilled into lung act as adjuvant for the production of IgE and IgG antibodies.