Distribution of porcine CD4/CD8 double-positive T lymphocytes in mucosa-associated lymphoid tissues.
The present study describes the distribution of CD4/CD8 double-positive (DP) T cells in lymph nodes and mucosa-associated lymphoid tissues of pigs at 6-7 months of age. Proportions of lymphocytes isolated from peripheral, bronchial and mesenteric lymph nodes expressing CD4 and/or CD8 molecules were similar and ranged from 10-13% CD4/CD8 DP cells, 25-27% CD4 single-positive (SP) cells, and 27-32% CD8 SP cells. Mucosa-associated lymphoid tissues had significantly smaller proportions of CD4+ and/or CD8+ T cells than lymph nodes and CD4/CD8 DP cells accounted for a larger proportion of the total CD4+ lymphocytes than in lymph nodes. Compared to the lymph nodes, the predominant CD4+ and/or CD8+ T-cell subset in tonsils was the CD4/CD8 DP population (18%), because of both a higher proportion of these cells and a lower proportion of CD4 SP (12%) and CD8 SP (14%) lymphocyte subsets. Jejunal Peyer's patches were comprised of 12% CD4 SP, 28% CD8 SP and 10% CD4/CD8 DP lymphocytes. In contrast, the mid-section of the continuous Peyer's patch in the ileum contained 7% CD4 SP, 8% CD8 SP and 4% CD4/CD8 DP lymphocytes. The distribution of T lymphocytes in porcine mucosal lymphoid aggregates agrees with the reported correlation between high and low rates of lymphocyte entry into these tissues and the abundance or scarcity of T cells, respectively. Defining the role of CD4/CD8 DP lymphocytes and their unique distribution in mucosa-associated lymphoid tissues in the pig may reveal novel T-cell-mediated regulatory pathways.
Zuckermann
F A
FA
Department of Veterinary Pathobiology, University of Illinois, Urbana 61801, USA.
Gaskins
H R
HR
D000818:Animals; D001980:Bronchi / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology*; D009092:Mucous Membrane / Q000276:immunology; D014066:Palatine Tonsil / Q000276:immunology; D013552:Swine / Q000276:immunology*; D016176:T-Lymphocyte Subsets; D013601:T-Lymphocytes / Q000276:immunology*
D015704:CD4 Antigens; D016827:CD8 Antigens