Vaccine-Induced Protection from Homologous Tier 2 SHIV Challenge in Nonhuman Primates Depends on Serum-Neutralizing Antibody Titers

Immunity. 2019 Jan 15;50(1):241-252.e6. doi: 10.1016/j.immuni.2018.11.011. Epub 2018 Dec 11.

Abstract

Passive administration of HIV neutralizing antibodies (nAbs) can protect macaques from hard-to-neutralize (tier 2) chimeric simian-human immunodeficiency virus (SHIV) challenge. However, conditions for nAb-mediated protection after vaccination have not been established. Here, we selected groups of 6 rhesus macaques with either high or low serum nAb titers from a total of 78 animals immunized with recombinant native-like (SOSIP) Env trimers. Repeat intrarectal challenge with homologous tier 2 SHIVBG505 led to rapid infection in unimmunized and low-titer animals. High-titer animals, however, demonstrated protection that was gradually lost as nAb titers waned over time. An autologous serum ID50 nAb titer of ∼1:500 afforded more than 90% protection from medium-dose SHIV infection. In contrast, antibody-dependent cellular cytotoxicity and T cell activity did not correlate with protection. Therefore, Env protein-based vaccination strategies can protect against hard-to-neutralize SHIV challenge in rhesus macaques by inducing tier 2 nAbs, provided appropriate neutralizing titers can be reached and maintained.

Keywords: ADCC; BG505; HIV vaccine; correlates of protection; neutralizing antibodies; non-human primates; tier 2 protection; vaccination.

Publication types

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

MeSH terms

  • AIDS Vaccines / immunology*
  • Animals
  • Antibodies, Neutralizing / immunology
  • HIV / physiology*
  • HIV Antibodies / immunology*
  • HIV Infections / immunology*
  • Humans
  • Macaca mulatta
  • Simian Acquired Immunodeficiency Syndrome / immunology*
  • Simian Immunodeficiency Virus / physiology*
  • Vaccination
  • env Gene Products, Human Immunodeficiency Virus / immunology*

Substances

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