An improved method for the rescue of recombinant Newcastle disease virus

Reverse genetics has been used to generate recombinant Newcastle disease virus with enhanced immunogenic properties for vaccine development. The system, which involves co-transfecting the viral antigenomic plasmid with three helper plasmids into a T7 RNA polymerase-expressing cell to produce viral progenies, poses a great challenge. We have modified the standard transfection method to improve the transfection efficiency of the plasmids, resulting in a higher titer of virus progeny production. Two transfection reagents (i.e., lipofectamine and polyethylenimine) were used to compare the transfection efficiency of the four plasmids. The virus progenies produced were quantitated with flow cytometry analysis of the infectious virus unit. The modified transfection method increased the titer of virus progenies compared with that of the standard transfection method. METHOD SUMMARY The standard transfection method was modified by changing the time to perform the co-transfection to produce viral progenies from the transfected mammalian cell line, which improved the titer of virus progenies. The method of viral titer quantification by infecting the cancer cell line was simple and time saving.