[Construction and immunological responses of recombinant adenovirus containing Epstein-Barr nuclear antigen 1 in...

This study aimed to construct recombinant adenovirus expressing Epstein-Barr nuclear antigen 1 (EBNA1) against nasopharyngeal carcinoma (NPC). The C-terminal region fragment of the ebna1 gene of Epstein-Barr virus was amplified from the standard strain B95-8 by polymerase chain reaction (PCR). The gene fragment was inserted into the pDC316 shuttle plasmid using the EcoRI and BgIII restriction enzyme sites. The pDC316-ebna1 shuttle plasmid and pBHG helper plasmid were cotransfected into HEK293 cells after sequencing. The soluble protein was extracted from HEK293 cells, which caused apparent cytopathic effects. The transcription and expression of the ebna1 gene were confirmed using flow cytometry and Western blotting. rAd-ebna1 titers were measured by the TCID50. rAd-ebna1 was injected into BALB/c mice at a dose of 2 x 10(8) VP per mouse, EBNA1 epitope-specific responses were measured at 1st, 2nd, 4th and 8th weeks post-immunization. The target fragment of ebna1 (939 bp) was obtained by PCR, and was in consensus with the sequence from the standard strain B95-8. Cytopathic effects were observed after the pDC316-ebna1 shuttle plasmid and pBHG helper plasmid were cotransfected into HEK293 cells. rAd-ebna1 was successfully recombined in HEK293 cells. EBNA1 protein was detected in HEK293 cells, rAd-ebna1 titers reached 10(8) TCID50/mL. Specific responses to CD4+ epitopes of EBNA1 were detected in the immunized mice. In conclusion, rAd-ebna1 was successfully constructed and induced specific responses to CD4+ epitopes of EBNA1 in immunized mice.