Immunological response of nasopharyngeal carcinoma patients to the Epstein-Barr-virus-coded thymidine kinase expressed in Escherichia coli.

A bacterial expression system which produces large amounts of the Epstein-Barr-virus-coded thymidine kinase has been developed and used to produce protein for Western blot analysis of a number of human antisera. Interestingly, only sera from nasopharyngeal carcinoma (NPC) patients had any detectable IgA antibody which reacted with the EBV TK. These findings provided the basis for ELISA tests using a crude lysate of the E. coli cells expressing the EBV TK as target antigen. Sera from NPC patients showed high levels of IgA reactive antibodies in this test while other sera did not.