Tetramer-positive CTL were found in both HAM/TSP patients and HCs. The mean frequency of HTLV-I-specific CTL does not differ between HAM/TSP patients and HCs (P = 0.58; two-tailed Mann–Whitney U-statistic). CD8+ cells from both A*0201+, A*0206+, and A*0207+ individuals bound the A*0201-Tax11–19 tetramer. ■, A*0206; ▴, A*0207; ○, A*0201; ●, A*0210, Δ A*0201/A*0206; ■, A*0201/A*0207; ×, mean % tetramer ± SE.