HLA-E-restricted, Gag-specific CD8⁺ T cells can suppress HIV-1 infection, offering vaccine opportunities

Human leukocyte antigen-E (HLA-E) normally presents an HLA class Ia signal peptide to the NKG2A/C-CD94 regulatory receptors on natural killer (NK) cells and T cell subsets. Rhesus macaques immunized with a cytomegalovirus-vectored simian immunodeficiency virus (SIV) vaccine generated Mamu-E (HLA-E homolog)-restricted T cell responses that mediated post-challenge SIV replication arrest in >50% of animals. However, HIV-1-specific, HLA-E-restricted T cells have not been observed in HIV-1-infected individuals. Here, HLA-E-restricted, HIV-1-specific CD8 T cells were primed in vitro. These T cell clones and allogeneic CD8 T cells transduced with their T cell receptors suppressed HIV-1 replication in CD4 T cells in vitro. Vaccine induction of efficacious HLA-E-restricted HIV-1-specific T cells should therefore be possible.