[Macrophage migration inhibition reaction in Marseilles fever]. / Reaktsiia tormozheniia migratsii makrofagov pri éksperimental'noi Marsel'skoi likhoradke.

Delayed type hypersensitivity (DTH) was studied in the macrophage migration inhibition test, antibody titers in the CFT and functional activity of spleen macrophages, obtained from guinea-pigs infected with R. conori, in cell cultures. No direct correlation between antibody synthesis and functional macrophage activity accompanied by the development of DTH was revealed. The most pronounced protective function of macrophages could be observed during the decrease of antibody titers and the extinction of DTH.

Differences in the susceptibility of mouse lines to the rickettsial pox agent.

A definite correlation between the susceptibility of spleen macrophage cultures derived from a highly susceptible mouse line (C57Bl/6) and a line with low susceptibility (DBA/2) and the susceptibility of these mouse lines to infection with Rickettsia acari was established. Intensive replication of the rickettsiae in cultures from highly susceptible animals caused marked disorders in cell metabolism and eventually death of the culture. Cell cultures derived from resistant mice gradually eliminated the rickettsiae by intracellular digestion; necrobiotic changes in them were insignificant.

Cytological investigation of Rickettsia tsutsugamushi infection of mice with different allotypic susceptibility to the agent.

Cytological and cytochemical studies on Swiss and random-bred white mice susceptible to Rickettsia tsutsugamushi infection as well as resistant C57 Black 6 and CBA mice revealed a clear-cut relationship between the severity of infection and the pattern of macrophage reaction. In highly susceptible mice the fatal infection was accompanied by death of macrophages and necrotisation of the peritoneal exudate cells. The resistant mice showed no clinical signs but developed an intensive macrophage reaction, and the main mass of the inoculated rickettsiae died at the inoculation site, the macrophages remaining viable. Phagocytosis and digestion of rickettsiae were accompanied by markedly increased activities of hydrolytic and oxidizing-reducing enzymes.