Clonotypically similar hybrid αβ T cell receptors can exhibit markedly different surface expression, antigen specificity and cross-reactivity.

Emerging data indicate that particular major histocompatibility complex (MHC)-bound antigenic peptides can be recognized by identical or near-identical αβ T cell receptors (TCRs) in different individuals. To establish the functional relevance of this phenomenon, we artificially paired α and β chains from closely related TCRs specific for the human leucocyte antigen (HLA)-B*35:01-restricted HIV-1 negative regulatory factor (Nef)-derived epitope VY8 (VPLRPMTY, residues 74-81). Several hybrid TCRs generated in this manner failed to express at the cell surface, despite near homology with naturally isolated αβ chain combinations. Moreover, a substantial proportion of those αβ TCRs that did express lost specificity for the index VY8 peptide sequence. One such hybrid αβ pair gained neo-variant specificity in the context of the VY8 backbone. Collectively, these data show that clonotypically similar TCRs can display profound differences in surface expression, antigen specificity and cross-reactivity with potential relevance for the control of mutable viruses.