Susceptibility of Rickettsia tsutsugamushi Gilliam to gamma interferon in cultured mouse cells.
Recombinant rodent gamma interferon (IFN-gamma) inhibited the infection of cultured BALB/3T3 mouse fibroblasts by Rickettsia tsutsugamushi Gilliam, apparently mainly by clearance of intracellular rickettsiae. No significant effect on rickettsial entry into the cells was noted; IFN-gamma was toxic to infected cells, as measured by the capacity of treated, infected cells to attach to the surfaces of culture vessels. In a small proportion of IFN-gamma-treated cells, rickettsial replication appeared to persist at normal levels. A fraction (28%) of rickettsiae clonally isolated from cultures treated with IFN-gamma was resistant to IFN-gamma-mediated inhibition, but four serial passages of these resistant clones in the absence of additional IFN-gamma resulted in the loss of resistance. In several respects, therefore, the IFN-gamma-mediated inhibition of scrub typhus rickettsiae in cultured fibroblasts was similar to that reported for Rickettsia prowazekii.
Hanson
B
B
Department of Microbiology and Immunology, University of Maryland, Baltimore 21201.
D016475:3T3 Cells; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000627:therapeutic use* / Q000633:toxicity; D051379:Mice; D008807:Mice, Inbred BALB C; D012285:Orientia tsutsugamushi / Q000254:growth & development / Q000276:immunology*; D011994:Recombinant Proteins; D012612:Scrub Typhus / Q000628:therapy*; D014364:Tryptophan / Q000494:pharmacology
D011994:Recombinant Proteins; D007371:Interferon-gamma; D014364:Tryptophan