Analysis of chicken mucosal immune response to Eimeria tenella and Eimeriamaxima infection by quantitative reverse transcription-PCR

The recent cloning of chicken genes coding for interleukins, chemokines, an d other proteins involved in immune regulation and inflammation allowed us to analyze their expression during infection with Eimeria. The expression l evels of different genes in jejunal and cecal RNA extracts isolated from un infected chickens and chickens infected with Eimeria maxima or E. tenella w ere measured using a precise quantitative reverse transcription PCR techniq ue. Seven days after E. tenella infection, expression of the proinflammator y cytokine interleukin-1 beta (IL-1 beta) mRNA was increased 80-fold. Among the chemokines analyzed, the CC chemokines K203 (200-fold) and macrophage inflammatory factor 1 beta (MIP-1 beta) (80-fold) were strongly upregulated in the infected ceca, but the CXC chemokines IL-8 and K60 were not. Howeve r, the CXC chemokines were expressed at very high levels in uninfected ceca l extracts. The levels of gamma interferon (IFN-gamma) (300-fold), inducibl e nitric oxide synthase (iNOS) (200-fold), and myelomonocytic growth factor (MGF) (50-fold) were also highly upregulated during infection with E. tene lla, whereas cyclooxygenase 2 showed a more modest (13-fold) increase. The genes upregulated during E. tenella infection were generally also upregulat ed during E. maxima infection but at a lower magnitude except for those enc oding MIP-1 beta and MGF. For these two cytokines, no significant change in expression levels was observed after E. maxima infection. CD3(+) intraepit helial lymphocytes may participate in the IFN-gamma upregulation observed a fter infection, since both recruitment and upregulation of the IFN-gamma mR NA level were observed in the infected jejunal mucosa. Moreover, in the chi cken macrophage cell line HD-11, CC chemokines, MGF, IL-1 beta, and iNOS we re inducible by IFN-gamma, suggesting that macrophages may be one of the ce ll populations involved in the upregulation of these cytokines observed in vivo during infection with Eimeria.