Distribution of porcine CD4/CD8 double‐positive T lymphocytes in mucosa‐associated lymphoid tissues

• Published in: Immunology Vol. 87; no. 3; pp. 493 - 499
• Main Authors: ZUCKERMANN, F. A., GASKINS, H. R.
• Format: Journal Article
• Language: English
• Published: Oxford BSL Blackwell Science Ltd 01.03.1996
• Subjects: Animals; Bronchi - immunology; CD4 Antigens - immunology; CD8 Antigens - immunology; Immunity, Mucosal; Intestinal Mucosa - immunology; Lymph Nodes - immunology; Lymphoid Tissue - cytology; Mucous Membrane - immunology; Palatine Tonsil - immunology; Swine - immunology; T-Lymphocyte Subsets; T-Lymphocytes - immunology
• ISSN: 0019-2805; 1365-2567
• DOI: 10.1046/j.1365-2567.1996.494570.x

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.