New developments in an old strategy: heterologous vector primes and envelope protein boosts in HIV vaccine design

ABSTRACT

Prime/boost vaccination strategies for HIV/SIV vaccine development have been used since the early 1990s and have become an established method for eliciting cell and antibody mediated immunity. Here we focus on induction of protective antibodies, both broadly neutralizing and non-neutralizing, with the viral envelope being the key target antigen. Prime/boost approaches are complicated by the diversity of autologous and heterologous priming vectors, and by various forms of envelope booster immunogens, many still in development as structural studies aim to design stable constructs with exposure of critical epitopes for protective antibody elicitation. This review discusses individual vaccine components, reviews recent prime/boost strategies and their outcomes, and highlights complicating factors arising as greater knowledge concerning induction of adaptive, protective immunity is acquired.

KEYWORDS:

• Vector prime/envelope boost vaccine strategy
• DNA
• adenovirus
• poxvirus vectors
• monomeric/trimeric envelope immunogens
• neutralizing/non-neutralizing antibody
• cellular immunity

Financial and competing interests disclosure

The authors were supported by the Intramural Research Program of the NIH, National Cancer Institute. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.