A T cell receptor Vα region selectively expressed in CD4⁺ cells

The peripheral TCR Vβ repertoire is strongly influenced by the processes of negative selection (deletion) and positive selection in the thymus. In order to investigate whether such selection events influence the Vα repertoire, we have produced an anti-Vα11 mAb. This antibody was made by immunization with a chimeric TCR:Ig protein containing Vα11 in place of the V(H) of an IgG2a,λ Ig. This scheme optimizes the specificity of immunization and facilitates the screening procedure. The anbtibody recognizes a panel of Vα11-expressing T cell clones. Analysis of mouse strains indicates that the antibody recognizes Vα11 only in mice of the C57 background. The expression of the epitope on peripheral T cells is strongly biased to the CD4⁺ subset, suggesting positive selection of Vα11 on class II MHC molecules. In some strain comparisons, the percentage of Vα11-expressing T cells in the CD4⁺ subset was elevated in I-E⁺ relative to I-E^- strains. These data suggest that Vα11 can differentially influence the selection of T cells into the CD4⁺/CD8⁺ subsets.