IDENTIFICATION OF THE COMPLETE EXPRESSED HUMAN TCR V-GAMMA REPERTOIREBY FLOW-CYTOMETRY

Five of the six expressed human TCR V(gamma)regions (V(gamma)2, 3, 4, 8 and 9) can be detected by available mAb, No mAb with specificity for the remaining V(gamma)5 region has been described, In this study, we have characterized mAb 56.3, which was obtained after immunization wit h V(gamma)2/3/4/9-negative thymic gamma delta cells, V-gamma transcrip ts were analyzed by inverse PCR and RT-PCR in 56.3(+) cell lines and c lones derived from peripheral blood, mAb 56.3 recognized all cells tha t expressed in-frame V(gamma)5 transcripts, In addition, mAb 56.3 reco gnized some but not all cells expressing V(gamma)3, but did not react with a large panel of clones expressing V(gamma)2, 4, 8 or 9, In combi nation with anti-V(gamma)2/3/4 mAb 23D12, V(gamma)5-expressing cells c ould be clearly identified as 56.3(+)23D12(-). In some donors, mAb 56. 3 also recognized a small fraction of TCR alpha beta cells, At the clo nal level, these cells expressed in-frame V(gamma)5-J(beta)-C-beta or V(gamma)3-J(beta)-C-beta trans-rearrangements. When mAb 56.3 was combi ned with V(gamma)2/3/4-, V(gamma)8- and V(gamma)9-specific mAb, all pe ripheral blood gamma delta T cells were stained, Thus, mAb 56.3 supple ments the panel of available TCR V-gamma-specific mAb, It is now possi ble to analyze the complete expressed human V-gamma repertoire by flow cytometry.