Infecção pelo Cryptosporodium sp., linhagem humana MMC, em camundongos C.B-17/Uni scid, C57BL/6/Uni bg, C3H/Uni nu e C57BL/6 KO para INF- gama

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Cryptosporidium is a protozoan parasite that can cause chronic life-threatening diarrhea in immunocompromised persons. In immunocompetent hosts, C. parvum causes a self-limiting diarrheal illness that can persist until 3 weeks. Cryptosporidium sp isolated ttom a HIV - positive patient in Campinas (Brazil) has been maintained by repeated oocyst passage through S.P.F. suckling mice. Differences in susceptibility to cryptosporidial infections were investigated among four immunodeticient adult mice strains: C57BL/6 gamma-interferon-knockout (KO), C57BL/6/Uni bg, C3H1Uni nu and C.B-17/Uni scid. The mice were infected via oral inoculation with 105 Cryptosporidium sp MMC oocysts and monitored for infection intensity by collection of fecal pellets ttom individual mice. After 15 or 44 days, the mice were sacriticed in order to evaluate the damage at distaljejunun, ileum, caecum and colono There was differences highly signiticant in the fecal oocyst shedding among KO, bg, scid, nu and adult immunocompetent controls (C57BL/6/Uni and BALB/c/Uni). The resistance pattem conceming the mortality and oocysts shedding among the mice strains, was: C 57BL/6>BALB/c>scid>bg>nude>KO. Histological intestinal evaluation 15 days after infection, showed that KO mice showed pronounced histological changes and scid mice were less infected. The response of the epithelium to cryptosporidial infection after 44 days showed signals of recovery and it was possible to suggest the following panel conceming the recovery capacity : scid>bg>nude>KO. The results of this study demonstrated that there is correlation between resistance pattem and histological alterations. These findings support theview that IFN-y, T and NK cells are very important for the control of infection meanly during the early recovery phase against Cryptosporidium sp infection. The results also suggest that the role of B cells in the resolution of murine infection against Cryptosporidium is minore

ASSUNTO(S)

interferon histopatologia protozoario intestinos camundongos - imunologia

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