The genetic diversity of HIV-1 envelope glycoproteins (Env) remains a major obstacle to the development of an antibody-based AIDS vaccine. In prior studies, we examined the breadth and magnitude of neutralizing antibody (NAb) responses in rhesus monkeys after immunization with DNA prime-recombinant adenovirus (rAd) boost vaccines encoding either single or multiple genetically distant Env immunogens. Using a standardized multi-tier panel of reference Env pseudoviruses for NAb assessment, we showed that monkeys immunized with a mixture of Env immunogens (clades A, B, and C) exhibited a greater breadth of NAb activity against neutralization sensitive Tier 1 viruses following both vaccination and challenge compared to monkeys immunized with a single Env immunogen (clade B or C). However, all groups of Env-vaccinated monkeys demonstrated only limited neutralizing activity against Tier 2 pseudoviruses, which are more characteristic of the neutralization sensitivity of circulating HIV-1. Additional immunogenicity studies are evaluating vectors with new Env inserts and various forms of soluble Env proteins. New antigens, structure based design of known neutralizing epitopes, are being evaluated.

Project Start
Project End
Budget Start
Budget End
Support Year
12
Fiscal Year
2013
Total Cost
$330,804
Indirect Cost
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State
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