IMMUNOLOGICAL ROLE OF HUMAN PALATINE TONSIL IN EPSTEIN-BARR-VIRUS PERSISTENCE

To determine whether EBV-specific cellular immunity persists and contr ols EBV in the palatine tonsil, we compared EBV-specific cellular immu ne responses in the palatine tonsil and peripheral blood. In 32 EBV-se ropositive donors, we performed in vitro growth inhibition assays of E BV-induced B-lymphocyte transformation (regression assay). The results showed that EBV-specific cytotoxic T lymphocytes (CTL) precursor freq uency was higher in the palatine tonsil than in the peripheral blood. After a first stimulation with autologous lymphoblastoid cell line (LC L), the EBV-specific cytotoxicity of reactivated CTL was higher in the palatine tonsil than in the peripheral blood. Furthermore EBV-specifi c CTL lines established from the palatine tonsil had significantly hig her EBV-specific cytotoxicity in comparison with those from the periph eral blood. Both the EBV-specific CTLs from tonsils and peripheral blo od were restricted by HLA class-I determinants. These data indicate th at the palatine tonsil, which is frequently exposed to EBV, plays an i mportant role in controlling EBV infection in the oropharynx.