Phenotypic classification of porcine lymphocyte subpopulations in blood and lymphoid tissues
The pig is a useful model for the heterogeneity of the mammalian immune system and has also recently received attention as a possible source of organs for human transplantation. Here we report a detailed analysis of porcine lymphocyte phenotypes. Peripheral blood αβ T cells consisted of four subsets (CD4+8−, CD4+8lo, CD4−8lo and CD4−8hi) and γδ T cells of three (CD2−4−8−, CD2+4−8lo and CD2+4−8−). There were, in addition, a large proportion of non-T-non-B lymphocytes with CD2+3−4−8lo surface immunoglobulin-negative phenotype containing natural killer (NK) activity. A striking observation was the relatively low frequency of αβ T cells in the blood of young pigs. Similar phenotypes were also identified in the cells from peripheral lymphoid tissues, though the proportions of the γδ T cells and the non-T-non-B lymphocytes in the lymph nodes and tonsil were much lower and the majority of the γδ T cells in the lymphoid tissues bore CD2 and/or CD8. In thymus, the small thymocytes were predominantly CD3−4+8+while the mature large thymocytes displayed phenotypes similar to those of peripheral T cells. Thus this work has directly defined porcine αβ and γδ T cells, demonstrated the T-cell nature of the unique CD4+8+ subset of peripheral lymphocytes, revealed the high heterogeneity of the CD8+ cells, and established the phenotype of NK cells. The functional properties of these defined porcine lymphocyte subsets can now be experimentally determined in health and disease.
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Document Type: Research Article
Affiliations: Immunology Division, BBSRC Institute for Animal Health, Pirbright, Surrey, UK
Publication date: September 1, 1996