Chimeric SHIV Gag Proteins Optimize T-Cell Response Against HIV Gag

HIV Gag has been included in nearly all HIV vaccines entering clinical trials because of its importance in SIV models and its correlation with protection in HIV-infected long-term non-progressors. However, HIV Gag has proven less immunogenic than Env in phase I clinical trial studies. Through sequence comparison, two regions in HIV Gag have been identified as contributing to the decreased immunogenicity observed for HIV Gag. Replacement of these regions with corresponding SIV sequences significantly increased the resulting T-cell response to HIV Gag in mice. Utilization of these chimera in an HIV vaccine could significantly enhance the overall immunogenicity of the vaccine.