HIV subtype A and subtype C infections induce high frequencies of TL9-specific CD8 T cells in subjects expressing HLA B42 or HLA B81. (A) The fraction of CD8 T cells that bound autologous or both subtype-specific TL9/HLA class I tetramers (y-axis) in relation to the infecting subtype and the presenting HLA class I molecule (x-axis). (B) Representative CD8 T cell–gated dot plots showing HLA class I–matched subtype-specific tetramer staining of PBMCs from B42⁺ or B81⁺ subjects infected with either subtype A (left panels) or subtype C (right panels).