ABSTRACT
Objective To explore the antigenicity of the recombinant respiration syncytial virus (RSV)fusion protein (amino acids 168-289) encoded by 546-881 bases of the fusion gene expressed in insect baculoviruses expression system.Methods The fragment F' of fusion gene 546-881 bases was amplified from viral RNA( Long strain ) by the reverse transcription-polymerase chain reaction(RT-PCR).F' was inserted into transfer vector pBacPAK9 and the recombinant plasmid pBacRSV F' was constructed.Sf9 insect cells were then co-transfeeted with a mixture of recombinant plasmids pBacRSV F' and linearized BacPAK6 viral DNA( Bsu36 Ⅰ -digested).The recombinant baculoviruses BacPAK F' was constructed and was able to express the recombinant protein in Sf9 insect cells.The recombinant protein was purified by Ni2+ NTA chromatography and its antigenicity was identified by Western blot(WB) analysis.Specimens including the nasopharyngeal aspirates(NPAs) and sera were collected from 33 infants and young children with acute lower respiration tract infection. Indirect immunofluorecenee assay (IFA) and WB were used to detect the RSV antigen in NPAs and the anti-RSV antibody in sera respectively.Results The recombinant protein (molecular weight 13 000) was expressed in Sf9 insect cells.WB analysis demonstrated that the purified recombinant protein had a specific RSV antibody-binding activity. The recombinant protein could be recognized by positive serum infected by RSV.The positive rate was 27.3% and 33.3% respectively.There was no significant difference between them(X2 = 0.29 ,P ＞ 0.05).Conclusion The recombinant respiratory syncytial virus fusion gene (546-881 bp) encoding protein is expressed in Sf9 insect cells and it has strong antigenicity and could have clinical application value for detection of RSV infection.