EPSTEIN-BARR-VIRUS GP350-SPECIFIC ANTIBODY-TITERS AND ANTIBODY-DEPENDENT CELLULAR CYTOTOXIC EFFECTOR FUNCTION IN DIFFERENT GROUPS OF PATIENTS - A STUDY USING CLONED GP350-EXPRESSING TRANSFECTED HUMAN T-CELL TARGETS

An NK cell activity-resistant human lymphoid T cell line (CEM-NKr) exp ressing the transfected Epstein-Barr virus (EBV) gp350 gene was used i n membrane immunofluorescence (MIF) and antibody-dependent cellular cy totoxicity (ADCC) assays to analyze the gp350-specific humoral and ADC C responses in groups of EBV-seropositive persons. Results show that t here is no correlation between gp350-specific ADCC-mediating antibody titers and MIF or EBV neutralizing antibody titers. For example, sera from patients in the acute phase of infectious mononucleosis, while po sitive by MIF assay or EBV neutralization test, were not reactive in t he ADCC assay. Results also show that nasopharyngeal carcinoma (NPC) p atients on MIF present high IgG titers against gp350 compared with hea lthy persons. Anti-gp350 IgA antibodies were detected in all groups te sted; however, titers were highest in the NPC group.