Submitted to: Developmental Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2008
Publication Date: 8/20/2008
Citation: Kim, D., Hong, Y.H., Park, M.S., Lamont, S.J., Lillehoj, H.S. 2008. Differntial immune-related gene expression in two genetically disparate chicken lines during infection by Eimeria maxima. Developmental Biology. 132:131-140. Interpretive Summary: In this paper, ARS scientists reports new findings from an immunogenetics study which was carried out in collaboration with scientists at the Iowa State University and show that genetic determinants within the chicken B complex influence the local and systemic expression of immune-related cytokine and chemokine response to Eimeria infection. Although conventional disease control strategies against avian coccidiosis have relied on prophylactic chemotherapy and vaccination, both methods have serious drawbacks. Genetic selection of disease resistant broiler lines offers an alternative to achieve this goal that may ultimately lead to the elimination of drugs in commercial poultry production. The Fayoumi breed, which originated in Egypt, was imported to the United States primarily because of its reported resistance to the avian leukosis. Derived from the original Fayoumi breed, the M5.1 and M15.2 congenic pair of lines share an identical genetic background and differ only in the major histocompatibility complex (MHC). In this study, M5.1 and M15.2 show quite different disease susceptibility and local cytokine response. Analysis of global transcriptional profiling data led to the identification of several novel genes which are involved in host innate immunity. These findings will provide basis for the development of genetic selection strategy by poultry industry.
Technical Abstract: Two M5.1 and M15.2 B complex congenic lines of Fayoumi chickens were evaluated for body weight loss and fecal oocyst counts as parameters of avian coccidiosis. M51 chickens exhibited the resistance to E. maxima compared with M15.2. To correlate the differential responses of the M5.1 and M15.2 lines to E. maxima infection with cellular immune responses, the expression levels of mRNAs encoding 14 immune-related molecules were measured by quantitative RT-PCR in intestinal intraepithelial lymphocytes (IELs) and splenocytes at 0, 3, 4, and 5 days following parasite infection. Intestinal IELs from M5.1 chickens expressed higher levels of transcripts encoding interferon-' (IFN-'), interleukin-1ß (IL-1ß), IL-6, IL-8, IL-12, IL-15, IL-17A, inducible nitric oxide synthase (iNOS), and lipopolysaccharide-induced tumor necrosis a factor (LITAF), and lower levels of mRNAs for IFN-a, IL-10, IL-17D, NK-lysin, and tumor necrosis factor superfamily 15 (TNFSF15), compared with the M15.2 line. In the spleen, E. maxima infection was associated with higher expression levels of IFN-', IL-15, and IL-8 and lower levels of IL-6, IL-17D, and IL-12 in M5.1 compared to M15.2 birds. Using an intestinal IEL cDNA microarray, the differential dynamics of gene expression in the gut of M5.1 and M15.2 chickens following experimental coccidiosis were evident. In particular, the genes encoding lymphotactin and parathymosin were expressed at significantly higher levels in M5.1 compared with M15.2 line chickens. We conclude that genetic determinants within the chicken B complex influence resistance to E. maxima infection by controlling the local and systemic expression of immune-related cytokine and chemokine genes.