Objective: To acquire stable expression of envelope proteins of hepatitis C virus in insect host cells and use the expressed envelope proteins for detecting the serums of patients with hepatitis C.
Methods: The envelope gene of HCV H strain was amplified by PCR and inserted in baculovirus vector BacPAK8, and then recombined with linear BacPAK6 DNA in insect cells. The recombinant baculoviruses were selected by the plaque assay. The insect cells were infected by the recombinant baculoviruses that contained the target gene produced E1, E2 proteins, which were characterized with the immunoblot assay and the immunofluorescence and were used to determine 35 serum samples of patients with hepatitis C.
Results: The expressed E1, E2 proteins showed that the relative molecular mass of E1 is about 21 x 10(3) and 33 x 10(3), and that of E2 is about 60 x 10(3). Detection of immunofluorescence indicated that E1, E2 proteins are localized in the cytoplasm of the infected cells. Four of the 35 serums responded to expressed E1; one of them was found to recognize E2 protein. Three of 9 serums which were HCV RNA positive by PCR testing got united to E1, E2.
Conclusion: The HCV envelope protein can be expressed stably in the insect cells. Expressed E proteins could be used in the serologic analysis of the patients' serums.