γδ T-cell receptor repertoire in human peripheral blood and thymus (original) (raw)

T-cell clones expressing the 3,5 T-cell receptor (Tcr) were generated from peripheral blood lymphocytes (PBLs) and from a thymus sample. In the panel of ten thymus-derived clones, four 3,5 Tcr phenotypes [as defined by the reaction of monoclonal antibodies (mAbs) directed against known I17 and I/6 regions] were identified. All the clones lacked expression of the V63 V region, while seven clones were V61 +. V61 was found in combination with V3"9 or with undefined V3" Vregions. In addition, two other 3"5 Tcr phenotypes were identified on these clones: V3'9 + V61-V63-and V3"9-V61-V63-. One of the clones expressed CD4 and another was CD8positive. The remaining clones were CD4-CD8-. In the panel of 76 PBL-derived, 3"5 Tcr-bearing clones, five 3,5 Tcr phenotypes could be identified. In contrast to the thymus-derived clones, 30% of the clones were V63 + whereas V61 was expressed by a minority of the clones only. One clone was CD4-positive and approximately 30% of the clones were CD8-positive. Four of the five mAb-defined 3'5 Tcr phenotypes could be identified on both thymus and PBL-derived T-cell clones. However, biochemical analysis of the Tcrs demonstrates differences in the usage of C3"1-and C3'2-encoded 3+ chains by T cells derived from the thymus and PBLs. The results therefore indicate that, at the clonal level, similarities and differences exist between the 3,5 Tcr repertoires expressed in the thymus and by PBLs. Furthermore, they indicate that combinatorial 3,5 Tcr heterogeneity is larger than has so far been described. The receptor diversity, combined with the potential of 3'5 Tcr + cells to express CD4 or CD8, indicates that these cells are a heterogeneous population that might mediate a number of immune functions.