HIGH-LEVEL EXPRESSION OF THE JAPANESE ENCEPHALITIS VIRUS-E PROTEIN BY RECOMBINANT VACCINIA VIRUS AND ENHANCEMENT OF ITS EXTRACELLULAR RELEASE BY THE NS3 GENE-PRODUCT

Recombinant vaccinia viruses expressing the prM and E genes of the Japanese encephalitis virus (JEV) were constructed by use of synthetic promoters. While the recombinant virus mOJ6-S(L), with an optimized vaccinia late-gene promoter, produced a 20-fold elevated level of E protein, as well as an 86-kDa precursor protein in infected cells, no significant quantitative difference was detected between the extracellular or cell-surface E protein produced by mOJ6-S(L) and those produced by mOJ6 with the 7.5-kDa promoter. However, when the cells were infected with Dengue 2 virus before infection with mOJ6-S(L), the amount of the extracellular E protein increased 16-fold. In addition, enhancement of its extracellular release was observed when cells were co-infected with mOJ6-S(L) and recombinant vaccinia virus expressing the NS3 gene of JEV. © 1993 Academic Press, Inc.