One TCR complex mediates both virus specificity and allo-HLA reactivity. To exclude that allo-HLA reactivity was mediated via another TCR than the virus-specific TCR, the TCR of 2 representative clones was transferred to T cells with a different specificity. (A) IE1/A1-specific T cells transduced with viral vectors encoding for the TCR of BRLF1/A3-specific clone 19 (IE1/A1+BRLF1 TCR) and IE1/A1-specific T cells transduced with a mock viral vector (IE1/A1+mock) were tested for allo–HLA-A*0201 reactivity against HLA-A*0201–positive EBV-LCLs (A*0201 pos LCLs), HLA-A*0201–negative EBV-LCLs (A*0201 neg LCLs), and HLA-A*0201–negative EBV-LCLs transduced with HLA-A*0201 (A*0201 td LCLs) and for BRLF1 specificity against BRLF1 peptide–loaded HLA-A*0301–positive EBV-LCLs (BRLF1pept /HLA-A3). (B) Pp50/A1-specific T cells transduced with viral vectors encoding for the TCR of VZV clone 7 (pp50/A1+VZV TCR) and pp50-specific T cells transduced with a mock viral vector (pp50/A1+mock) were tested for allo–HLA-A*0205 reactivity against HLA-A*0205–positive EBV-LCLs (A*0205 pos LCLs), K562 cells (K562), and K562 cells transduced with HLA-A*0205 (K562+A*0205) and for VZV specificity against VZV-IE62 peptide–loaded HLA-A*0201–positive EBV-LCLs (VZVpept/HLA-A2). The results demonstrate that virus specificity and allo-HLA reactivity exerted by virus-specific T cells were mediated by 1 TCR complex. Experiments are shown in duplicate, mean values are shown ± SD.