Detection of EBV-LMP2-specific cell responses and EBV DNA copies in IgA/EBV-VCA positive individuals and patients with nasopharyngeal carcinoma

Objective To investigate the correlation between EBV-LMP2-specific cell responses, EBV DNA copies and titers of IgA antibody to viral capsid antigen (IgA/VCA). Methods IgA/VCA antibody were tested with immune-enzyme method. Both of plasma and lymphocytes were respectively separated from IgA/VCA-positive individuals and patients with nasopharyngeal carcinoma (NPC) without treatment. EBV DNA copies and LMP2-specific cell responses were detected by interferon-gamma Elispots assay and fluorescent quantitative PCR method. Results IgA/VCA antibody in 80 of 1 233 individuals was positive in Cangwu county, and the positive rate is 6%. EBV-LMP2-specific cell responses and EBV DNA copies were detected in 72 of 80 IgA/VCA positive individuals and patients with NPC. EBV DNA copies in plasma were increased with rise of titers of IgA/VCA antibody, while EBV-LMP2-specific cell responses were declined. Conclusion EBV-LMP2-specific cell responses and EBV DNA copies are probably associated with titers of IgA/VCA antibody. Key words: IgA/ EBV-VCA; latent membrane protein 2; Cell responses; EBV DNA