Multi-parameter exploration of HIV-1 virus-like particles as neutralizing antibody immunogens in guinea pigs, rabbits

Tommy Tong1, Ema T Crooks1, Keiko Osawa1

  • 1Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, CA 92121, USA.

Virology
|June 4, 2014
PubMed

Virus-like particles (VLPs) offer a platform to test the hypothesis that, since antibody binding to native envelope glycoprotein (Env) trimers results in HIV-1 neutralization, that native Env trimers presented in membranes may be useful for inducing neutralizing antibodies (nAbs) in a vaccine setting. So far, VLPs have not fulfilled this potential. Here, using a "shotgun" approach, we evaluated a wide cross-section of variables in a series of VLP immunizations. We identified 3 tentative leads. First, that VLP doses may not have been sufficient for optimal nAb induction. Second, that dampening the antigenicity of non-functional Env (for example uncleaved gp160) using either protease digests or IgG masking may be useful. Third, that guinea pig sera preferentially target non-conserved epitopes and exhibit relatively high background activity, suggesting that rabbits may be preferable as small animal vaccine models. Recent immunogenicity studies in rabbits appear to bear out all 3 of these leads.

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