Interferon- is expressed in both gut and spleen during Eimeria tenella infection

The effect of primary infection and subsequent challenge with Eimeria tenella on interferon- (IFN-) production in the spleen and caeca of Light Sussex chickens was assessed. The ability of splenocytes to proliferate and produce IFN- in response to mitogen stimulation ex vivo was determined. Differences in the kinetics of IFN- production suggested that the spleens of infected birds contain a subpopulation of T cells, primed to produce IFN-, which migrate from the spleen in response to a secondary infection. IFN- mRNA expression was detected by hybridization of an anti-sense chicken IFN- riboprobe 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- expression in chickens at the site of E. tenella infection, and also the first indication that IFN- may be involved in the immune response to challenge.