Effects of recombinant bovine interferon γ onStrongyloides papillosusinfection in calves

Abstract

AbstractThe effects of interferon (IFN) γ on the course of infection withStrongyloides papillosusin calves were investigated. Calves (N=7 each) were inoculated with recombinant bovine IFNγ or control solution daily from day 0 to day 15 followingS. papillosusinfection. Treatment with IFNγ induced an increase in faecal egg output in the peak stage of infection. The IFNγ-treated animals harboured more worms, especially more immature worms, in the small intestine than control animals at necropsy on day 17, with no decreases in intestinal mucosal mast cells. Both animal groups had similar small numbers of intestinal worms at necropsy on day 26. All control animals developed peripheral blood eosinophilia on day 7, while five of seven IFNγ-treated animals did not. Serum α1-acid glycoprotein concentrations increased on day 7 in both animal groups, with higher values in control animals than in IFNγ-treated animals. Control animals mounted a predominant IgG1 response toS. papillosusfrom day 10, while IFNγ-treated animals did from day 22. These data suggested that IFNγ inhibited some host protective responses toS. papillosusmigrating larvae, resulting in an improvement of worm survival after a period when protective responses should be activated during the early stage of infection. The effects of IFNγ on intestinal worm expulsion should be confirmed by further experiments.