title: The interaction in vitro of Pneumocystis carinii with macrophages and L-cells.
abstract: A model was developed for studying the interaction between Pneumocystis, rat-derived cells, and humoral factors. Pneumocystis were obtained in large quantity by bronchial lavage of steroid-treated rats. The trophozoite was the predominant form obtained, and it could readily be recognized by phase contrast microscopy. Organisms maintained a typical morphology for at least 3 days in culture, and 10-20% took up radiolabeled nucleotides. Pneumocystis readily adhered to cell surfaces in a similar manner in alveolar macrophages from steroid-treated or normal rats, mouse peritoneal macrophages, and L-cells. Adherent organisms were not interiorized to a significant degree in the absence of antipneumocystis serum. After addition of rabbit antipneumocystis serum, rapid interiorization of organisms occurred from the surface of macrophages but not L-cells. Organisms appeared to be promptly destroyed within macrophages after interiorization. Persisting or multiplying intracellular forms were not seen. Antipneumocystis serum did not morphologically alter Pneumocystis. These observations suggest a role for antibody and mononuclear phagocytes during the immune response to Pneumocystis.
mesh_terms: D000818:Animals; D000906:Antibodies; D002478:Cells, Cultured; D007739:L Cells; D008264:Macrophages / Q000276:immunology*; D008297:Male; D008858:Microscopy, Phase-Contrast; D010587:Phagocytosis; D011010:Pneumocystis / Q000276:immunology*; D051381:Rats
chemical_list: D000906:Antibodies