Constructions of vaccinia virus A-type inclusion body protein, tandemly repeated mutant 7.5 kDa protein, and hemagglutinin gene promoters support high levels of expression.

We devised vaccinia virus (VV)-based vector systems that support higher levels of expression of cloned genes in the early and late phases of the infection cycle than reported previously. Enhanced expression can be obtained by combining the promoter of the A-type inclusion body protein gene, the mutated early region of the 7.5-kDa gene promoter (7.5-kDa promoter), and the promoter of the hemagglutinin (HA) gene. One construct produced 60 micrograms/10(6) cells of chloramphenicol acetyltransferase (CAT), equivalent to 10-18% of total cell protein. Another construct produced about seven times more CAT during the early phase than the amount synthesized under the control of the 7.5-kDa promoter alone. The envelope proteins of human immunodeficiency virus type I synthesized during the early phase of infection were more active as immunogens than these proteins synthesized during the late phase, regardless of the amounts produced.