A particular TCR β variable region used by T cells infiltrating kidney transplants

Immune tolerance to MHC class II identical renal grafts is achievable in miniature swine following a short immunosuppressive treatment, Like in clinical transplants, swine-accepted allografts are primarily infiltrated by CD8(+) T cells, which are noncytotoxic to the renal tissue. However, the actual specificity and function of these intragraft-infiltrating lymphocytes remain poorly understood. To develop the molecular tools to study TCR-associated functions of graft-infiltrating cells in a preclinical transplantation model, we have determined the nucleotide sequence of 19 pig V beta, 12 J beta, and two D beta. Sequence comparisons identified 17 different V beta families and two J beta clusters homologous to the human J beta1 and J beta2. The fact that the pig J beta1 segments were always found joined to the D beta1-like sequence in numerous rearranged TCR beta cDNA suggests the existence of two D-J clusters in swine. These results also imply that the polymorphism of the porcine TCR beta segments is similar to that found in human. Finally, we report the discovery of a new and functional V beta subfamily named V beta 100, which exhibited similarity to the murine V beta2 sequence but had no described V beta homolog in humans. Pilot spectratyping studies on V beta usage revealed a clonal dominance of V beta 100(+) T cell subsets among infiltrating cells in two accepted grafts. The Journal of Immunology, 2001, 166: 2589-2596.