[Influence of nonessential region on protective efficacy of recombinant fowlpox viruses].
Because of the interference of maternal antibodies, the recombinant fowlpox virus (rFPV) vaccine has not been used widely. The selection of a well-defined FPV nonessential region might be a desirable way to solve this problem. Two pairs of primers were designed according to the genome of a pathogenic FPV to amplify two flanking regions (FPV1 and FPV2) of the supposed nonessential region by PCR, and then a series of plasmid vectors were constructed to generate the expression vector pP12LS, which containing FPV1, FPV2, the expression cassette of P11-LacZ reporter gene and the promoter Ps. To abtain the vector pP12LSF, the F gene of ZJ1 strain Newcastle Disease Virus (NDV) was inserted into pP12LS, in which the F gene was located downstream of the promoter Ps. pP12LSF was transfected into chicken embryo fibroblast (CEF) pre-nfected with 282E4 strain FPV. The recombinant FPV, rFPV-FSC, was purified by blue plaque selection. The LacZ and F genes could be expressed by rFPV-FSC after 20 successive passages in CEF. The FPV nonessential region was the only difference between rFPV-FSC and rFPV-FSB. These two rFPVs could induce completely protection in SPF chickens against lethal challenge with F48E8 strain NDV. However, the protective efficacy showed a significant difference in commercial chickens with maternal antibodies. The protective efficacy of rFPV-FSC was 100% and rFPV-FSB was 61.54%. The results indicate that the selection of a well-defined FPV nonessencial region is an effective way to increase the protective efficacy of rFPVs, especially in chickens with maternal antibodies.
Animal Infectious Disease laboratory, Ministry of Agriculture, Yangzhou University, Yangzhou 225009, China. sunlei362@126.com
Lei
L
Sun
Wu-jie
WJ
Liu
Su-juan
SJ
Chen
Huo-ying
HY
Shi
Xiu-fan
XF
Liu
D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D002645:Chickens; D005587:Fowlpox virus / Q000235:genetics* / Q000276:immunology; D005822:Genetic Vectors; D009522:Newcastle disease virus / Q000235:genetics* / Q000276:immunology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D014162:Transfection; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
D014614:Vaccines, Synthetic; D014765:Viral Vaccines