Subpopulations Of Swine Gamma Delta T Cells Defined By Tcr Gamma And Wc1 Gene Expression

gamma delta T cells constitute a major portion of lymphocytes in the blood of both ruminants and swine. Subpopulations of swine gamma delta T cells have been distinguished by CD2 and CD8 alpha expression. However, it was not clear if they have distinct expression profiles of their T-cell receptor (TCR) or WC1 genes. Identifying receptor expression will contribute to understanding the functional differences between these subpopulations and their contributions to immune protection. Here, we annotated three genomic assemblies of the swine TCR gamma gene locus finding four gene cassettes containing C, J and V genes, although some haplotypes carried a null TRGC gene (TRGC4). Genes in the TRGC1 cassette were homologs of bovine TRGC5 cassette while the others were not homologous to bovine genes. Here we evaluated three principal populations of gamma delta T cells (CD2(+)/SWC5(-), CD2(-)/SWC5(+), and CD2(-)/SWC5(-)). Both CD2(-) subpopulations transcribed WC1 co-receptor genes, albeit with different patterns of gene expression but CD2(+) cells did not. All subpopulations transcribed TCR genes from all four cassettes, although there were differences in expression levels. Finally, the CD2(+) and CD2(-) gamma delta T-cell populations differed in their representation in various organs and tissues, presumably at least partially reflective of different ligand specificities for their receptors.