Immunological Response to Clostridium perfringens in Two Genetically Divergent Lines of Chickens as Influenced by Major Histocompatibility Complex (MHC) Genotype
Sumners, Lindsay Hart
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Chickens genetically selected for low (LA) or high (HA) antibody response to sheep red blood cells (SRBC) displayed a correlated change in major histocompatibility complex (MHC), so that LA chickens were 96% B13 and HA chickens were 96% B21. During a clinical outbreak of necrotic enteritis, B21B21 genotypes experienced significantly less mortality (6% vs. 13 %) compared to B13B13 genotypes. A study was carried out to assess immunological differences between LA and HA lines during exposure to Clostridium perfringens. In Experiment 1, chickens were orally gavaged with a low (10^7 CFU/mL) or high (10^9 CFU/mL) dose of C. perfringens. In Experiment 2, chickens were orally gavaged with live coccidia oocysts on experiment d 1, followed by 107 CFU/mL C. perfringens on d 5. Unfortunately, establishment of necrotic enteritis infection was unsuccessful in both experiments as evidenced by lack of significant intestinal lesions, as well as no negative effect on bird performance. In an ex vivo study, peripheral blood mononuclear cells (PBMCs) were isolated from each genetic line, cultured, stimulated with LPS (4 h), and exposed to varying concentrations of C. perfringens Î±- toxin (1, 10, 100, 1000 U/L) for 2 and 4 h. Evaluation of cellular proliferation, percent cytotoxicity and immunological gene expression was carried out in a variety of experiments. Genetic lines were found to be highly divergent in all analyses.
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