A novel α/β T-cell clone with broad reactivity against human clear cell renal cell carcinomas (RCC) was generated from a patient with renal cancer. The T-cell receptor (TCR) from this clone recognizes soluble TNF-related apoptosis inducing ligand bound to death receptor 4, a complex found on the surface of nearly all RCC. In this study, we modified this novel TCR by introducing amino acid (AA) substitutions in its complementarity determining region 2 (CDR2) and CDR3 regions of both chains, to increase its activity. We demonstrated that tumor recognition by PBL, retrovirally-transduced with these TCRs, was decreased or unchanged by substitutions in the TCR beta chain, and in the CDR2α region. Yet some AA substitutions in the CDR3α region at positions 109 and 112 could augment tumor recognition. Specifically, substituting phenylalanine for tyrosine at AA109 (109Y-F) and alanine or lysine for serine at AA112 (112S-K or 112 S-A) augmented tumor recognition. Increased benefit was seen on combining both AA substitutions and a retrovirus encoding the modified TCR 109Y-F/112S-K conferred the best tumor recognition to transduced PBL. This modified TCR retained the recognition pattern of parental clone HC/2G-1 against RCC lines, other tumors and normal tissues. These results document that CDR3α plays an important role in the interaction of the HC/2G-1 TCR and its novel ligand. A phase I/II clinical trial, adoptively transferring autologous PBL transduced with this modified TCR has just begun in patients with metastatic RCC.
Published by Elsevier B.V.