The bovine T cell receptor alpha/delta locus contains over 400 V genes and encodes V genes without CDR2

alpha beta T cells and gamma delta T cells perform nonoverlapping immune functions. In mammalian species with a high percentage of very diverse gamma delta T cells, like ruminants and pigs, it is often assumed that alpha beta T cells are less diverse than gamma delta T cells. Based on the bovine genome, we have created a map of the bovine TRA/TRD locus and show that, in cattle, in addition to the anticipated > 100 TRDV genes, there are also > 300 TRAV or TRAV/DV genes. Among the V genes in the TRA/TRD locus, there are several genes that lack a CDR2 and are functionally rearranged and transcribed and, in some cases, have an extended CDR1. The number of bovine V genes is a multiple of the number in mice and humans and may encode T cell receptors that use a novel way of interacting with antigen.