Epstein-Barr virus (EBV)-specific cellular cytotoxic activities of tonsillar lymphocytes (TL) and peripheral blood lymphocytes (PBL) obtained from the 26 same donors were investigated. The minimum cell concentration of TL required for regression of EBV-transformation, 3.1±2.1× 104/ml, was significantly lower (p<.01) than that of PBL, 4.3±2.6×104/ml, indicating that the EBV-specific cell-mediated cytotoxicity of TL was significantly higher than that of PBL. The cytotoxic activity against an autologous EBV-positive B-lymphoblastoid cell line (LCL) of the tonsillar T-lymphocytes, 10.8±3.7%, was significantly higher than that of the peripheral blood T-lymphocytes, 5.9±1.6%, after co-cultivation with an autologous-LCL (p<.05). The EBV-specific cytotoxic T-lymphocytes (CTL) lines, which contained>95% CD8-positive cells, established from TL, had significantly higher cytotoxic activities against autologous-LCL (73.1± 16.5%) than did the CTL lines established from PBL (59.0±16.4%, p<.01). The number of tonsillar T-lymphocytes which showed regression against in vitro EBV-transformation was significantly higher in patients with tonsillar focal infection, 2276±901 cells/well, than in patients with simple tonsillar hypertrophy, 991±350cells/well, (p<.05), suggesting that the regression activity of tonsillar T-lymphocytes was significantly lower in patients with tonsillar focal infection than in patients with simple tonsillar hypertrophy. These data show that TL have higher EBV-specific cytotoxicities than PBL, suggesting that the tonsils may play an important role in defense against EBV.
