| In order to develop genetic engineered vaccines which are safe, convenient for use for different avian diseases, we designed a series of experiments to reach the goal.Construction of recombinant fowlpox virus coexpressing MDV gB and AIV HA. For construction of fowlpox virus (FPV) transfer vector, the promoter PS was removed and inserted into nonessential region of FPV from FPV7S to form 7SP. MDV gB gene of CVI988/Rispens strain in PVLgB and AIV HA gene of F strain in 1175HA was removed and inserted into 7SP to construct transfer vector 7SPLGA. Recombinant fowlpox viruses (rFPVs) coexpressing MDV gB and AIV HA gene were constructed by using different promoters of PS and P7.5 .Construction of recombinant fowlpox virus coexpressing AIV HA and NDV F. For the construction of transfer vector pFGS11HAF, AIV HA gene of F strain in puc18HA and NDV F gene of F48E8 strain in PUC19F were removed and inserted into PFGS11. Recombinant fowlpox viruses (rFPV)coexpressing AIV HA gene and NDV F gene were constructed by using different promoters of PS and PE/L.Recombinant rFPVs were derived by DOSPER liposome-mediated transfection with the two transfer vectors on chicken embryo fibroblast (CEF) monolayer cultures which were infected by wild type FPV Chinese vaccine strain 282E4 3-4 hours earlier. Recombinant FPVs were selected and purified by blue plaques expressing 3 -galactosidase..The expression of foreign genes in rFPVs were confirmed by IFA.Trails for evaluating protective efficacy of rFPVs against very virulent MDV or AIV challenge. Vaccination trials were carried out in SPF chickens, protection index(PI) against Md5+RBIB challenge induced by 106 PFU rFPV-gB-HA was 53.8 while PI against AIV challenge induced by 106 PFU rFPV-gB-HA was 69.5. The results in this study showed that recombinant rFPVs coexpressing HA and gB induced promising protective immunity in vaccinated chickens. |
PDF Full Text Request