Expression of the Newcastle Disease Virus Fusion Glycoprotein in Vero Cells Using Attenuated Salmonella typhimurium as Transgenic Carrier

FANG Wei-Huan^*, LIANG Xue-Ya
( Institute of Preventive Veterinary Medicine, Zhejiang University, Hangzhou 310029, China )

Abstract    The full-length cDNA of fusion protein (F) gene of newcastle disease virus (NDV)strain F48E9 was amplified by RT-PCR and inserted into pcDNA3 under the control of human cytomegalovirus (hCMV) immediate early enhancer and promoter. The resulting recombinant plasmid pcDNA3-F was transformed by electroporation into attenuated Salmonella typhimurium strain ZJ111 (dam^- and phoP^-), which was then used to transfect the Vero cells. The DNA and RNA dot blotting revealed that the F gene was transcribed into mRNA in the Vero cells. There was expression of the F protein as shown by indirect immunofluorescent assay. The expression began at 48 h post-infection and increased thereafter, as indicated by ELISA. A 55 kD band of the F protein was identified by SDS-PAGE and Western blotting. These results clearly show that the expressed fusion protein was immuno-reactive with chicken anti-NDV serum.
Key words    newcastle disease virus; fusion glycoprotein; attenuated Salmonella typhimurium; DNA vaccine vector

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