title: Electron microscopic analysis of in vitro interaction of Rickettsia prowazekii with guinea pig macrophages. I. Macrophages from nonimmune animals.
abstract: Monolayer cultures of peritoneal macrophages of intact guinea pigs were infected with Rickettsia prowazekii (strain Breinl) and examined by electron microscopy after 30 min, 4 and 24 hr post-infection (p.i.). Three parallel processes developed in infected macrophages: reproduction of rickettsiae in macrophage cytoplasm, destruction in phagolysosomes and production of spheroplast-like forms. Reproduction of rickettsiae yielded 2 cell types: those with dense and with light cytoplasm; they were located side by side in the microcolony and seemed to have a common capsule-like coat. Relatively small spheroplast-like forms of about 1 micron in size were regularly detected. Addition of immune serum to macrophages increased the number of rickettsiae, both of rod-shaped as well as of spheroplast-like ones located within phagosomes, but elicited no increase in the number of digested pathogen cells.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D006168:Guinea Pigs; D007106:Immune Sera; D008264:Macrophages / Q000276:immunology / Q000382:microbiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010588:Phagosomes / Q000382:microbiology / Q000648:ultrastructure; D012283:Rickettsia prowazekii / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D013104:Spheroplasts / Q000648:ultrastructure; D014438:Typhus, Epidemic Louse-Borne / Q000276:immunology
chemical_list: D007106:Immune Sera