Amino Acid Changes in the HIV-1 gp41 Membrane Proximal Region Control Virus Neutralization Sensitivity.
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.
Bradley, T; Trama, A; Tumba, N; Gray, E; Lu, X; Madani, N; Jahanbakhsh, F; Eaton, A; Xia, S-M; Parks, R; Lloyd, KE; Sutherland, LL; Scearce, RM; Bowman, CM; Barnett, S; Abdool-Karim, SS; Boyd, SD; Melillo, B; Smith, AB; Sodroski, J; Kepler, TB; Alam, SM; Gao, F; Bonsignori, M; Liao, H-X; Moody, MA; Montefiori, D; Santra, S; Morris, L; Haynes, BF
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