The degree of HIV-1 amino acid variability is strictly related to different disease progression rates

Elite controllers and lessons learned for HIV-1 cure

Following the success of HIV-1 antiviral treatment that maintains undetectable levels of viral replication and lack of clinical progression, the design of an HIV-1 cure for patients became the next objective. The success of the treated individuals together with the identification of subjects that spontaneously control the clinical progression for long periods, such as long-term non-progressors (LTNPs) and particularly LTNP Elite Controllers (LTNP EC) have shed hope for the feasibility of a potential cure. Although a successful cure has not been attained yet, these patients have provided critical information on the mechanisms involved in the clinical control such as host genetic factors, as well as strong immune responses against the virus. Less attention has been paid to virological factors, particularly the association of the genetic variability and the control of viral infection. Considering all these studies, it has become clear that a combination of several host, immune and viral factors is needed to attain control of the viral replication control and the non-progressor clinical phenotype. Because this control can be reached through different combinations of factors, this group of individuals is not homogenous. As HIV-1 cure has been shown to be extremely difficult to achieve, a more feasible objective is the functional cure of the viral infection. After the analysis of multiple studies on the mechanisms of control in LTNP EC, we found subjects with various host protective factors and prolonged viral control. These subjects present a complete lack of evolution after more than 20-30 years of infection, stable levels of CD4+ cells (>400-500 cells/μl), a strong immune response, and no signs of clinical progression. We propose that individuals with these characteristics could have attained a functional cure of the HIV-1 infection.

Unusual Cysteine Content in V1 Region of gp120 From an Elite Suppressor That Produces Broadly Neutralizing Antibodies

Although it is now possible to produce recombinant HIV envelope glycoproteins (Envs) with epitopes recognized by the 5–6 major classes of broadly neutralizing antibodies (bNAbs), these have failed to consistently stimulate the formation of bNAbs in immunized animals or humans. In an effort to identify new immunogens better able to elicit bNAbs, we are studying Envs derived from rare individuals who possess bNAbs and are able to control their infection without the need for anti-retroviral drugs (elite supressors or ES), hypothesizing that in at least some people the antibodies may mediate durable virus control. Because virus evolution in people with the ES only phenotype was reported to be limited, we reasoned the Env proteins recovered from these individuals may more closely resemble the Envs that gave rise to bNAbs compared to the highly diverse viruses isolated from normal progressors. Using a phenotypic assay, we screened 25 controllers and identified two for more detailed investigation. In this study, we examined 20 clade B proviral sequences isolated from an African American woman, who had the rare bNAb/ES phenotype. Phylogenetic analysis of proviral envelope sequences demonstrated low genetic diversity. Envelope proteins were unusual in that most possessed two extra cysteines within an elongated V1 region. In this report, we examine the impact of the extra cysteines on the binding to bNAbs, virus infectivity, and sensitivity to neutralization. These data suggest structural motifs in V1 can affect infectivity, and that rare viruses may be prevented from developing escape.