Phagocytosis by alveolar cells studied by electron microscopy and microanalysis: Comparison of two types of particles

Abstract Rats or guinea pigs were injected intratracheally with identical doses of inorganic atmospheric particles of comparable particle size distributions. The particles behave differently as a function of their chemical nature. Illite (rats) and glass fibers (guinea pigs) are thus phagocytosed by different cell types, have different transit times in alveoli, and have different toxicities. Illite particles are phagocytosed primarily by alveolar macrophages and the constituents of these particles remain in cells for up to 8 months; inhaled particles are thus well supported by the animals. Glass particles are phagocytosed by alveolar macrophages and type I pneumocytes. These particles remain in alveoli for very short times and rapidly cause the animal's death. These results are discussed.