The interaction in vitro of Pneumocystis carinii with macrophages and L-cells.

• DOI: 10.1084/jem.147.1.157
• Publication Date: 2004-06-23T21:00:50Z
• Authors: H Masur; T C Jones
• Keywords: Male; 0303 health sciences; Pneumocystis; Macrophages; Antibodies; Rats; 3. Good health; 03 medical and health sciences; L Cells; Phagocytosis; Animals; Microscopy, Phase-Contrast; Cells, Cultured

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.