A pantothenate suxotroph of BCG rxpressing Gag confers enhanced HIV-specific immunogenicity compared to wildtype and perfingolysin expressing strains

In tuberculosis vaccine studies, perfingolysin expressing strains (pfo) of recombinant Mycobacterium bovis (rBCG) have been shown to enhance immunogenicity as compared to wildtype strains whilst pantothenate auxotrophic strains (ΔpanCD) have been shown to be safer and more immunogenic. Our group has recently shown that rBCGΔpanCD expressing HIV-1 Gag is more immunogenic than the wildtype Pasteur strain of BCG in the murine model. In this study, a wild type strain, a ΔpanCDstrain, a pfo strain and a ΔpanCD strain expressing perfringolysin (ΔpanCDpfo) of Danish BCG were used as vectors to express HIV-1 subtype C Gag. Gag specific immune responses induced by a prime with each rBCG-Gag vaccine and boost with modified vaccinia Ankara (MVA) were compared.