Characterization of the antibody response to the latent infection terminal proteins of Epstein-Barr virus in patients with nasopharyngeal carcinoma.

Human sera were tested for antibodies against the Epstein-Barr virus (EBV) latent infection terminal proteins (TPs). Anti-TP IgG and IgA antibodies were detected by an indirect immunofluorescence assay of insect cells expressing a recombinant TP1. Out of 301 human sera of patients with EBV-related and EBV-unrelated disorders, only sera from patients with nasopharyngeal carcinoma (NPC) (32/83; 38%) showed anti-TP antibodies. Studies on serial sera from German and Hong Kong NPC patients revealed a decline of anti-TP antibodies during tumour therapy, and none of these antibodies were identified in patients with early tumour stages or in remission. Comparative studies of TP1-specific polyclonal rabbit antisera and human TP-positive sera showed clear differences in the TP epitopes recognized by each. Human antisera contained antibodies only to native epitopes in exons 2 to 7 of TP1 whereas rabbit antisera reacted only with epitopes located in the first exon and, additionally, exhibited EBV strain specificities.