Characterization of a rat monoclonal antibody specific for a determinant encoded by the Vβ7 gene segment. Depletion of Vβ7⁺ T cells in mice withg Mls-1^a haplotype

We have generated a rat mAb, TR310, which recognizes a determinant encoded by the murine Vβ7 gene segment of the TCR. TR310 immunoprecipitates TCR from cell lysates, co-modulates with CD3, and can be used for immunofluorescence staining of T cells. By using this antibody, we found that the average percentage of Vβ7⁺ peripheral T cells in Mls-1^b mice was 3.8%, but only 0.8% in Mls-1^a mice. A similar difference was also observed in the mature TCR(hi) thymocyte subsets, suggesting that Vβ7⁺ T cells are deleted during intrathymic maturation in Mls-1^a mice. TR310 should prove to be a valuable reagent in further studies of the TCR repertoire and the analysis of factors which alter it.