Objective To construct the eukaryotic expression vector of human papillomavirus type18E5 and EGFP fusion gene,to analyze E5 expression in BALB/c3T3 cell.Methods The HPV18E5 and EGFP gene were amplified by polymerase chain reaction,and pSecTag-HPV18 E5-EGFP fusion gene eukaryotic expression vector was constructed by the method of digestion ligation and transformation.The recombinant plasmid was transfected into BALB/c3T3 cells with lipofectamine and the expressed product was detected by RT-PCR,the aim gene expression was observed under fluorescence microscope.Results The success in construction of pSecTag-HPV18 E5-EGFP fusion gene eukaryotic expression vector,RT-PCR result showed that HPV18E5 gene could be expressed in BALB/c 3T3 cell,fluorescent light could be observed under fluorescence microscope.Conclusion pSecTag-HPV18 E5-EGFP fusion gene eukaryotic expression vector has been successfully constructed,the recombinant plasmid could be expressed in BALB/ c3T3 cell.

Objective: To detect the presence of HPV associated antibodies in the serum of patients diagnosed with esophageal cancer in Chaoshan region and to provide data that could possibly be used as reference for the monitoring of patients with esophageal cancer. Methods: The pSecTag recombinant vectors containing the HPV16 E6/E7 and HPV18 E6/E7 genes were constructed respectively to express HPV16 E6/E7 and HPV18 E6/E7 fusion proteins in 293 cell line after transfecting the cell line. Immunoenzymatic method was employed with the fusion proteins as antigen to detect IgG antibody against HPV in serum of 76 esophageal cancer patients and 149 normal persons undergoing health checkup. In addition, the same sera were assessed by enzyme-linked immunosorbent assay (ELISA) method using L1 as antigen. Results: Only one esophageal cancer patient’s serum presented as positive for IgG by immunoenzyme technique when E6/E7 was used as antigen. However, when the L1 was used as antigen in ELISA assay, 37 of the 76 cases of esophageal cancer patients (48.7%) were HPV antibody-positive. Among the 149 health checkup persons, 79 (53.0%) were HPV antibody-positive. No significant difference was found between the two groups (P>0.05). Conclusion HPV related antibodies in the serum remain inapplicable as a screening tool for serological detection of esophageal cancer. Further research is needed to understand the role and diagnostic applications of HPV infection in esophageal cancer.