Concomitant detection of HLA-E tetramer ligand, Tax, and CD56 antigens in PBMCs isolated from a HTLV-1–infected individual. (A) PBMCs isolated from a HAM/TSP patient were cultivated for 6 hours in vitro. Tax protein was detected with the Lt-4 mAb. Staining with HLA-E tetramer and Lt-4 is shown. (B) Staining with Lt-4 and CD56-PC5 mAb. One representative experiment of 3 is shown.