Importance of early gamma interferon production in Propionibacterium acnes-induced resistance to Toxoplasma gondii infection in mice.
Treatment of mice with heat-killed Propionibacterium (P.) acnes conferred transient protection against Toxoplasma infection. To investigate the mechanism of this nonspecific resistance, the production of gamma interferon (IFN-gamma) by P. acnes-injected mice was evaluated in comparison with that by noninjected controls upon infection with Toxoplasma. Mice pretreated with this bacterium produced significantly more IFN-gamma than that produced by control mice up to 24 hr of infection. A single injection of anti-IFN-gamma MAb on day 0 but not later than day 3 of infection resulted in a total abrogation of the resistance conferred by P. acnes. Likewise, daily injection of cyclosporin A (Cs-A), a potent inhibitor of T cell function, during the first 3 days of Toxoplasma infection severely exacerbated the infection, in accordance with a marked suppression of the early IFN-gamma production. In contrast, the administration of Cs-A for 3 consecutive days starting at day 4 had no significant consequence on P. acnes-induced anti-toxoplasma resistance, while it reduced greatly the ability of P. acnes-injected mice to produce IFN-gamma in the later phase of infection. Moreover, no significant increase in mortality and suppression of IFN-gamma production was noted in mice receiving anti-asialo GM1 antibody. These results suggest that the early IFN-gamma production by T cells is an essential event for the establishment of P. acnes-induced anti-toxoplasma resistance in mice.
Shirahata
T
T
Department of Veterinary Microbiology, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
Shimoi
A
A
Kanda
H
H
Goto
H
H
Nakane
A
A
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001428:Bacterial Vaccines / Q000494:pharmacology*; D016572:Cyclosporine / Q000494:pharmacology; D004334:Drug Administration Schedule; D005260:Female; D007113:Immunity, Innate; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000097:blood; D051379:Mice; D008813:Mice, Inbred ICR; D011425:Propionibacterium acnes / Q000276:immunology*; D013997:Time Factors; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000517:prevention & control
D000911:Antibodies, Monoclonal; D001428:Bacterial Vaccines; D007371:Interferon-gamma; D016572:Cyclosporine