Susceptibility differences to Cryptosporidium parvum infection in two strains of gamma interferon knockout mice.
Differences in susceptibility to cryptosporidial infections were investigated between 2 strains of gamma interferon knockout (GKO) mice. Male C57BL/6J-Ifg and BALB/c-Ifg (GKO) mice, ages 8-10 wk, were inoculated with infectious oocysts at various doses. C57BL/6J-Ifg mice developed overwhelming infections and died 9-12 days after infection. Low inoculum doses (1 x 10(3)) did not increase the survival time significantly. The infection intensity in C57BL/6J-Ifg mice inoculated with 1 x 10(5) oocysts/mouse increased markedly on day 4 postinfection (PI) and continued to increase significantly over the next 6-7 days. Most of the C57BL/6J-Ifg mice exceeded 15% weight loss and died by day 10 PI. In contrast, BALB/c-Ifg mice developed moderate infections from which they recovered. The average parasite load in the BALB/c-Ifg mice was 100 times lower than in C57BL/6J-Ifg mice. Mice survived until termination of the experiment (39 days) even when 1 x 10(6) oocysts per mouse were used for inoculation. BALB/c-Ifg mice did not exhibit significant weight loss (or difference in stool consistency). These 2 mouse strains make excellent models for studying differences in recovering and nonrecovering immune mechanisms.
Mead
J R
JR
Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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D000818:Animals; D002417:Cattle; D003457:Cryptosporidiosis / Q000276:immunology*; D016785:Cryptosporidium parvum; D004198:Disease Susceptibility; D005243:Feces / Q000469:parasitology; D007371:Interferon-gamma / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout
D007371:Interferon-gamma