CD4, CD8 and TCR defined T-cell subsets in thymus and spleen of 2- and 7-week old commercial broiler chickens.
To better understand immune development and function in meat-type chickens (broilers), the proportions of T-cells expressing CD4, CD8, and T-cell receptors (TCR) in the thymus and spleen were determined by three-color fluorescence and flow cytometry in 2- and 7-week old broilers raised in commercial growing conditions. Broiler thymocytes consisted of single-(CD4+CD8- and CD4-CD8+) and double-(CD4+CD8+) positive subpopulations. Within these CD4+ and/or CD8+ thymocyte populations, all types of TCR (y delta, V beta 1 alpha beta, and V beta 2 alpha beta) could be identified. In the thymus, percentages of CD4+CD8- cells increased, CD4-CD8+ cells remained unchanged, and CD4+CD8+ cells decreased between 2 and 7 weeks of age. In the spleen, in addition to single-positive lymphocytes, double-positive populations were identified, expressing either y delta or alpha beta TCR. The percentage of CD4+CD8- splenocytes decreased, and the percentages of both CD4-CD8+ and CD4+CD8+ splenocytes increased between 2 and 7 weeks of age. Age-associated shifts in TCR usage (the proportion of cells expressing a certain type of TCR) were observed in the single-positive, but not in the double-positive, T-cell populations of both thymus and spleen. This multiparameter cell population analysis in broilers demonstrates thymic and splenic T-cell subsets similar to those previously described in layers. Differences in the proportions among T-cell subsets between 2- and 7-week old broilers likely reflect a more competent immune system in the older birds.
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Department of Poultry Science, University of Arkansas, Fayetteville 72701, USA. gferf@comp.uark.edu
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D000375:Aging / Q000276:immunology; D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D016827:CD8 Antigens / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002645:Chickens / Q000033:anatomy & histology / Q000254:growth & development / Q000276:immunology*; D007107:Immune System / Q000254:growth & development; D018655:Lymphocyte Count; D008297:Male; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell