Jr. Mead et Xd. You, SUSCEPTIBILITY DIFFERENCES TO CRYPTOSPORIDIUM-PARVUM INFECTION IN 2 STRAINS OF GAMMA-INTERFERON KNOCKOUT MICE, The Journal of parasitology, 84(5), 1998, pp. 1045-1048
Differences in susceptibility to cryptosporidial infections were inves
tigated between 2 strains of gamma interferon knockout (GKO) mice. Mal
e C57BL/6J-Ifg(tml@) and BALB/c-Ifg(tml@) (GKO) mice, ages 8-10 wk, we
re inoculated with infectious oocysts at various doses. C57BL/6J-Ifg(t
ml@) mice developed overwhelming infections and died 9-12 days after i
nfection. Low inoculum doses (1 x 10(3)) did not increase the survival
time significantly. The infection intensity in C57BL/6J-Ifg(tml@) mic
e inoculated with 1 x 10(5) oocysts/mouse increased markedly on day 4
postinfection (PI) and continued to increase significantly over the ne
xt 6-7 days. Most of the C57BW6J-Ifg(tml@) mice exceeded 15% weight lo
ss and died by day 10 PI. In contrast, BALB/c-Ifg(tml@) mice developed
moderate infections from which they recovered. The average parasite l
oad in the BALB/c-Ifg(tml@) mice was 100 times lower than in C57BL/6J-
Ifg(tml@) 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(tml@) mice did not exhibit significant weight loss (or dif
ference in stool consistency). These 2 mouse strains make excellent mo
dels for studying differences in recovering and nonrecovering immune m
echanisms.