Study on the expression and purification of Epstein-Barr virus DNA polymerase and its application to diagnosis of nasopharyngeal carcinoma.
In order to establish a simple, rapid, sensitive and specific assay for diagnosis of nasopharyngeal carcinoma (NPC), we prepard Epstein-Barr virus (EBV) DNA polymerase antigen by genetic engineering. DNA polymerase was expressed in BL21(DE3) using pRSET vector. The expressed product was characterized by SDS-PAGE and Western-blot. The IgG antibody angainst DNA polymerase of EBV in sera of NPC patients can be testified by expressed DNA polymerase through Western-blot and ELISA. The DNA polymerase is divided into the front 1/3 and the last 2/3 A2 parts, on A2 the antigenicity of DNA ploymerase locates. The sensitivity and specificity of Western-blot for detecting A2/IgG antibody was 80% and 100% respectively. The ELISA test established to detect A2/IgG antibody in sera of 46 NPC patients and 46 non-NPC patients also showed high sensitivity (89%) and specificity (93%).