Interleukin-12 enhances murine survival against acute toxoplasmosis.
Protective immunity against Toxoplasma gondii is mediated by the host cellular immune response. Interleukin-12 (IL-12), a recently described cytokine that stimulates NK cells to produce gamma interferon (IFN-gamma), is able to enhance host protection against this parasite in SCID mice. Administration of IL-12 to A/J mice significantly increased survival over that of control mice when IL-12 was delivered early in the course of acute infection. If it was administered at day 3 or thereafter, there was no observed difference in mortality between treated and control mice. Antibody depletion of IL-12 increased susceptibility to infection, as measured by mortality, only when the IL-12 was administered before day 3 postinfection. Mice treated with IL-12 at day 0 postinfection exhibited a significant rise above the control in both IL-2 and IFN-gamma production. Once infection has been established in the host (3 days), administration of exogenous IL-12 is unable to alter parasite-induced downregulation of IFN-gamma production. Thus, IL-12 appears to play an important, but transitory, role in protection against acute infection with T. gondii in the normal murine host.
Khan
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IA
Department of Medicine, Dartmouth Medical School, Hanover, New Hampshire 03755.
Matsuura
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T
Kasper
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LH
D000208:Acute Disease; D000818:Animals; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12; D007376:Interleukin-2 / Q000096:biosynthesis; D007378:Interleukins / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000401:mortality
D007376:Interleukin-2; D007378:Interleukins; D018664:Interleukin-12; D007371:Interferon-gamma