PHAGOLYSOSOMAL MORPHOLOGY AND DISSOLUTION OF COBALT OXIDE PARTICLES BY HUMAN AND RABBIT ALVEOLAR MACROPHAGES

The effect of phagolysosomal size on dissolution of cobalt oxide parti cles was evaluated in two different macrophage systems: alveolar macro phages (AM) of human smelters with phagolysosomes enlarged by ingested cigarette smoke products, and rabbit AM incubated in vitro with sucro se, which causes swelling of the phagolysosomes by osmosis. Human AM f rom smokers and nonsmokers were studied in vitro. There was no signifi cant difference in particle dissolution between AM obtained from smoke rs and nonsmokers, although there was a clear difference in the morpho logical appearance of AM, including significantly larger phagolysosome s in smokers. Rabbit AM were incubated for 24 or 72 h with or without 80 mM sucrose in the medium. The sucrose-treated cells had 3-4 times l arger phagolysosomes than untreated cells, with no major change in pha golysosomal pH. The increased size of the phagolysosomes did not affec t the ability of the AM to dissolve cobalt oxide particles. Furthermor e, rabbit AM showed the same ability as human AM to dissolve the cobal t oxide particles, in spite of the fact that they had markedly smaller phagolysosomes. Another difference between human and rabbit AM was th at phagolysosomes in human AMs increased In size with time in culture, while rabbit AM phagolysosomes decreased in size.