Identification of the complete expressed human TCR V(γ) repertoire by flow cytometry

Abstract

Five of the six expressed human TCR V(γ) regions (V(γ)2, 3, 4, 8 and 9) can be detected by available mAb. No mAb with specificity for the remaining V(γ)5 region has been described. In this study, we have characterized mAb 56.3, which was obtained after immunization with V(γ)2/3/4/9-negative thymic γδ cells. V(γ) transcripts were analyzed by inverse PCR and RT-PCR in 56.3+ cell lines and clones derived from peripheral blood. mAb 56.3 recognized all cells that expressed in-frame V(γ)5 transcripts. In addition, mAb 56.3 recognized some but not all cells expressing V(γ)3, but did not react with a large panel of clones expressing V(γ)2, 4, 8 or 9. In combination with anti-V(γ)2/3/4 mAb 23D12, V(γ)5-expressing cells could be clearly identified as 56.3+23D12-. In some donors, mAb 56.3 also recognized a small fraction of TCR αβ cells. At the clonal level, these cells expressed in-frame V(γ)5-J(β)-C(β) or V(γ)3-J(β)-C(β) trans-rearrangements. When mAb 56.3 was combined with V(γ)2/3/4-, V(γ)8- and V(γ)9-specific mAb, all peripheral blood γδ T cells were stained. Thus, mAb 56.3 supplements the panel of available TCR V(γ)-specific mAb. It is now possible to analyze the complete expressed human V(γ) repertoire by flow cytometry.