Effects of neutralizing antibodies on escape from CD8+ T-cell responses in HIV-1 infection

Enhancing broadly neutralising antibody suppression of HIV by immune modulation and vaccination

Although HIV infection can be managed with antiretroviral drugs, there is no cure and therapy has to be taken for life. Recent successes in animal models with HIV-specific broadly neutralising antibodies (bNAbs) have led to long-term virological remission and even possible cures in some cases. This has resulted in substantial investment in human studies to explore bNAbs as a curative intervention for HIV infection. Emerging data are encouraging, but suggest that combinations of bNAbs with other immunomodulatory agents may be needed to induce and sustain long-term viral control. As a result, a number of clinical trials are currently underway exploring these combinations. If successful, the impact for the millions of people living with HIV could be substantial. Here, we review the background to the use of bNAbs in the search for an HIV cure and how different adjunctive agents might be used together to enhance their efficacy.

Analysis of HIV-1 envelope evolution suggests antibody-mediated selection of common epitopes among Chinese former plasma donors from a narrow-source outbreak

The HIV-1 envelope mutates rapidly to evade recognition and killing, and is a major target of humoral immune responses and vaccine development. Identification of common epitopes for vaccine development have been complicated by genetic variation on both virus and host levels. We studied HIV-1 envelope gp120 evolution in 12 Chinese former plasma donors infected with a purportedly single founder virus, with the aim of identifying common antibody epitopes under immune selection. We found five amino acid sites under significant positive selection in ≥50% of the study participants, and 22 sites consistent with antibody-mediated selection. Despite strong selection pressure, some sites housed a limited repertoire of amino acids. Structural modelling revealed that most of the variable amino acid sites were located on the exposed distal edge of the Gp120 trimer, whilst invariant sites clustered within the centre of the protein complex. Two sites, flanking the V3 hypervariable loop, represent novel antibody sites. Analysis of HIV-1 evolution in hosts infected with a narrow-source virus may provide insight and novel understanding of common epitopes under antibody-mediated selection. If verified in functional studies, such epitopes could be suitable as targets in vaccine development.