Sequential immunization of macaques elicits heterologous neutralizing antibodies targeting the V3-glycan patch of HIV-1 Env

Sci Transl Med. 2021 Nov 24;13(621):eabk1533. doi: 10.1126/scitranslmed.abk1533. Epub 2021 Nov 24.

Abstract

Broadly neutralizing antibodies (bNAbs) against HIV-1 develop after prolonged virus and antibody coevolution. Previous studies showed that sequential immunization with a V3-glycan patch germline-targeting HIV-1 envelope trimer (Env) followed by variant Envs can reproduce this process in mice carrying V3-glycan bNAb precursor B cells. However, eliciting bNAbs in animals with polyclonal antibody repertoires is more difficult. We used a V3-glycan immunogen multimerized on virus-like particles (VLPs), followed by boosting with increasingly native-like Env-VLPs, to elicit heterologous neutralizing antibodies in nonhuman primates (NHPs). Structures of antibody/Env complexes after prime and boost vaccinations demonstrated target epitope recognition with apparent maturation to accommodate glycans. However, we also observed increasing off-target antibodies with boosting. Eight vaccinated NHPs were subsequently challenged with simian-human immunodeficiency virus (SHIV), and seven of eight animals became infected. The single NHP that remained uninfected after viral challenge exhibited one of the lowest neutralization titers against the challenge virus. These results demonstrate that more potent heterologous neutralization resulting from sequential immunization is necessary for protection in this animal model. Thus, improved prime-boost regimens to increase bNAb potency and stimulate other immune protection mechanisms are essential for developing anti–HIV-1 vaccines.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • AIDS Vaccines* / immunology
  • Animals
  • Antibodies, Heterophile / immunology
  • Antibodies, Neutralizing / immunology
  • HIV Antibodies* / immunology
  • HIV Infections* / immunology
  • HIV Infections* / prevention & control
  • HIV-1
  • Immunization / methods
  • Macaca
  • Polysaccharides
  • env Gene Products, Human Immunodeficiency Virus / immunology*

Substances

  • AIDS Vaccines
  • Antibodies, Heterophile
  • Antibodies, Neutralizing
  • HIV Antibodies
  • Polysaccharides
  • env Gene Products, Human Immunodeficiency Virus