Interferon-γ is expressed in both gut and spleen duringEimeria tenellainfection

The effect of primary infection and subsequent challenge with Eimeria tenella on interferon-gamma(IFN-gamma) production in the spleen and caeca of Light Sussex chickens was assessed. The ability of splenocytes to proliferate and produce IFN-gammain response to mitogen stimulation ex vivo was determined. Differences in the kinetics of IFN-gammaproduction suggested that the spleens of infected birds contain a subpopulation of T cells, primed to produce IFN-gamma, which migrate from the spleen in response to a secondary infection. IFN-gammamRNA expression was detected by hybridization of an anti-sense chicken IFN-gammariboprobe to splenic sections from infected birds and caecal sections from challenged birds. Hybridization was to T-cell areas in the spleen, and to cells in the lamina propria and intraepithelial compartments of the caecum. This is the first direct demonstration of IFN-gammaexpression in chickens at the site of E. tenella infection, and also the first indication that IFN-gammamay be involved in the immune response to challenge.