IMGT(®) Biocuration and Comparative Analysis of Bos taurus and Ovis aries TRA/TRD Loci

The adaptive immune response provides the vertebrate immune system with the ability to recognize and remember specific pathogens to generate immunity, and mount stronger attacks each time the pathogen is encountered. T cell receptors are the antigen receptors of the adaptive immune response expressed by T cells, which specifically recognize processed antigens, presented as peptides by the highly polymorphic major histocompatibility (MH) proteins. T cell receptors (TR) are divided into two groups, [Formula: see text] and [Formula: see text] , which express distinct TR containing either [Formula: see text] and [Formula: see text] , or [Formula: see text] and [Formula: see text] chains, respectively. The TR [Formula: see text] locus (TRA) and TR [Formula: see text] locus (TRD) of bovine (Bos taurus) and the sheep (Ovis aries) have recently been described and annotated by IMGT(®) biocurators. The aim of the present study is to present the results of the biocuration and to compare the genes of the TRA/TRD loci among these ruminant species based on the Homo sapiens repertoire. The comparative analysis shows similarities but also differences, including the fact that these two species have a TRA/TRD locus about three times larger than that of humans and therefore have many more genes which may demonstrate duplications and/or deletions during evolution.