title: Lymphocyte subpopulations in peripheral blood of lambs experimentally infected with Pasteurella haemolytica.
abstract: The lymphocyte subpopulations in peripheral blood obtained from eleven lambs experimentally infected with Pasteurella haemolytica were compared with those obtained from eight control lambs by flow cytometry, using a panel of monoclonal antibodies against specific lymphocyte epitopes. Experimental infection with P. haemolytica was characterized by a transient but significant reduction in SBU-T1+ (CD5+) T cells and SBU-T4+ (CD4+ or helper) T lymphocytes (P less than 0.05) and a significant rise in lymphocytes which did not express the LCA p220 epitope and the pan T cell surface marker (CD5-LCA p220-) ("null"). The reductions in CD5+ and CD4+ lymphocytes occurred 24 h after experimental infection, returning to preinoculation levels 5 days post inoculation (DPI). Five to 9 days after experimental infection, there was a significant increase in the number of lymphocytes, which expresses the pan T cell surface marker (CD5+) but which were CD4-CD8-. Lymphocyte transformation responses to the mitogen phytohaemagglutinin (PHA) were significantly reduced 24 h after experimental infection with P. haemolytica (P less than 0.05).
authors.affiliation: University of Liverpool, Department of Veterinary Pathology, Neston, Wirral, UK.
authors.forename: R
authors.initials: R
authors.lastname: Sharma
authors.forename: Z
authors.initials: Z
authors.lastname: Woldehiwet
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D000943:Antigens, Differentiation / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes; D018956:CD5 Antigens; D005434:Flow Cytometry; D007958:Leukocyte Count / Q000662:veterinary; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology; D012766:Pasteurellosis, Pneumonic / Q000097:blood*; D012756:Sheep; D012757:Sheep Diseases / Q000097:blood*; D006377:T-Lymphocytes, Helper-Inducer
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D018956:CD5 Antigens