Optimization of a multi-gene HIV-1 recombinant subtype CRF02_AG DNA vaccine for expression of multiple immunogenic forms

We developed an AIDS vaccine for Western and West-Central Africa based on a DNA plasmid vector expressing HIV-1 recombinant subtype CRF02_AG gag , pol , and env genes. To optimize the production of noninfectious HIV-like particles (VLPs) and potentially improve the effectiveness of the vaccine, we generated four potential vaccine constructs: the parental (IC2) and three modifications (IC25, IC48, and IC90) containing mutations within the HIV protease. While the parental construct IC2 expressed aggregates of Gag proteins, the IC25 construct resulted in the production of immature VLPs (the core comprises unprocessed Pr 55Gag ). The remaining two constructs (IC48 and IC90) produced mature VLPs (the core comprises processed capsid p24) in addition to immature VLPs and aggregates of Gag proteins. VLPs incorporated significant levels of mature gp120 envelope glycoprotein. Importantly, the mature VLPs were fusion competent and entered coreceptor-specific target cells. The production of multiple antigenic forms, including fusion-competent VLPs, by candidate DNA vaccine constructs may provide immunologic advantages for induction of protective cellular and humoral responses against HIV-1 proteins.