Journal of virology, 90(7), pp.3446-3457

Conformational epitope-specific broadly neutralizing plasma antibodies obtained from an HIV-1 clade C-infected elite neutralizer mediate autologous virus escape through mutations in the V1 loop

Patil, S., Kumar, R., Deshpande, S., Samal, S., Shrivastava, T., Boliar, S., Bansal, M., Chaudhary, N.K., Srikrishnan, A.K., Murugavel, K.G. and Solomon, S.

This study investigates the neutralizing antibody response in an Indian HIV-1 clade C-infected elite neutralizer and its ability to target a broad spectrum of HIV-1 pseudoviruses from different clades. The plasma from this individual demonstrated potent cross-neutralization (93% neutralization of 57 pseudoviruses), but mapping studies revealed that the antibodies did not recognize known broadly neutralizing antibody (BCN) epitopes such as the CD4 binding site, gp41 membrane-proximal external region, or specific glycans in the V1-V3 region. The neutralization was significantly reduced when the plasma was depleted using trimeric Env, suggesting that the plasma mainly targets epitopes on cleaved trimeric Env. Notably, mutation of residues in the V1 loop of the autologous circulating Envs was associated with neutralization resistance, highlighting how the virus can escape immune pressure. These findings provide new insights into epitope recognition by elite neutralizers and underscore the potential for trimeric Env as a target for HIV-1 vaccine development, particularly in clade C-infected populations, where neutralization escape may occur through V1 loop mutations.