EBioMedicine (Oct 2016)

Amino Acid Changes in the HIV-1 gp41 Membrane Proximal Region Control Virus Neutralization Sensitivity

  • Todd Bradley,
  • Ashley Trama,
  • Nancy Tumba,
  • Elin Gray,
  • Xiaozhi Lu,
  • Navid Madani,
  • Fatemeh Jahanbakhsh,
  • Amanda Eaton,
  • Shi-Mao Xia,
  • Robert Parks,
  • Krissey E. Lloyd,
  • Laura L. Sutherland,
  • Richard M. Scearce,
  • Cindy M. Bowman,
  • Susan Barnett,
  • Salim S. Abdool-Karim,
  • Scott D. Boyd,
  • Bruno Melillo,
  • Amos B. Smith III,
  • Joseph Sodroski,
  • Thomas B. Kepler,
  • S.Munir Alam,
  • Feng Gao,
  • Mattia Bonsignori,
  • Hua-Xin Liao,
  • M. Anthony Moody,
  • David Montefiori,
  • Sampa Santra,
  • Lynn Morris,
  • Barton F. Haynes

DOI
https://doi.org/10.1016/j.ebiom.2016.08.045
Journal volume & issue
Vol. 12, no. C
pp. 196 – 207

Abstract

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Most HIV-1 vaccines elicit neutralizing antibodies that are active against highly sensitive (tier-1) viruses or rare cases of vaccine-matched neutralization-resistant (tier-2) viruses, but no vaccine has induced antibodies that can broadly neutralize heterologous tier-2 viruses. In this study, we isolated antibodies from an HIV-1-infected individual that targeted the gp41 membrane-proximal external region (MPER) that may have selected single-residue changes in viral variants in the MPER that resulted in neutralization sensitivity to antibodies targeting distal epitopes on the HIV-1 Env. Similarly, a single change in the MPER in a second virus from another infected-individual also conferred enhanced neutralization sensitivity. These gp41 single-residue changes thus transformed tier-2 viruses into tier-1 viruses that were sensitive to vaccine-elicited tier-1 neutralizing antibodies. These data demonstrate that Env amino acid changes within the MPER bnAb epitope of naturally-selected escape viruses can increase neutralization sensitivity to multiple types of neutralizing antibodies, and underscore the critical importance of the MPER for maintaining the integrity of the tier-2 HIV-1 trimer.