Tricistronic Plasmid Expressing the T7 RNA Polymerase and Measles Virus N and P Proteins for Rescue of Measles Virus AIK-C Strain

Up to now, several attenuated measles virus vaccine strains derived from the Edmonston B vaccine consisting of Schwarz/Moraten, Zagreb, and AIK-C have been introduced for the rescue of their relative viruses through reverse genetics. In most studies, the measles virus rescue was done by supplying a cell line that expresses T7 RNA polymerase and measles virus N and P proteins as accessory proteins. The present study aimed to evaluate the rescue efficiency of the recombinant measles virus AIK-C vaccine strain by using a tricistronic expression plasmid. In this study, the rescue of the recombinant measles virus AIK-C vaccine strain was performed by co-transfection of three plasmids, including the cloned antigenomic cDNA of measles virus, a tricistronic expression plasmid that contained T7 RNA polymerase and measles virus N and P genes, and measles virus L polymerase expression plasmid. To increase the rescue efficiency, the transfected HEK-293 cells were co-cultured with Vero cells. As a result, the use of tricistronic expression plasmid that concomitantly encoded three necessary genes for the rescue of the measles virus led to the viral cytopathic effect with high efficacy five days post-transfection. Finally, the co-culture of transfected HEK-293 cells with Vero cells showed a relatively fast induction of viral cytopathic effect.