UCLA1, a synthetic derivative of a gp120 RNA aptamer, inhibits entry of human immunodeficiency virus type 1 subtype C.

Entry of human immunodeficiency virus type 1 (HIV-1) into cells is mediated by the virion surface envelope (Env) glycoproteins, making it a desirable target for antiretroviral entry inhibitors. We previously isolated a family of gp120 binding RNA aptamers and showed that they neutralized the infectivity of HIV-1. In this study, we assessed the activity of a shortened synthetic derivative of the B40 aptamer, called UCLA1, against a large panel of HIV-1 subtype C viruses. UCLA1 tightly bound to a consensus HIV-1 subtype C gp120 and neutralized isolates of the same subtype with 50% inhibitory concentrations (IC(50)s) in the nanomolar range. The aptamer had little toxicity in tests with cell lines and primary cells. Furthermore, it exhibited high therapeutic indices, suggesting that it may be effective at very low doses. Mapping of UCLA1 binding sites on gp120 revealed eight amino acid residues that modulated neutralization resistance. This included residues within the coreceptor binding site, at the base of the V3 loop, and in the bridging sheet within the conserved V1/V2 stem-loop of gp120. The aptamer was also shown to have synergistic effects with T20, a gp41 fusion inhibitor, and IgG1b12 (b12), an anti-CD4 binding site monoclonal antibody. These results suggest that UCLA1 may be suitable for development as a potent HIV-1 entry inhibitor.

Prevalence and severity of anxiety symptoms among family members of nyaope users in Tshwane, South Africa.

Background: Nyaope is a strongly addictive novel psychoactive substance that is commonly used in predominantly black townships in South Africa. The undesired behaviours of the users result in family members developing mental health challenges. Nyaope users often commit petty crimes, including stealing from families and neighbours. Aim: The aim of this study was to quantify anxiety symptoms among family members of nyaope users in Tshwane, South Africa. Setting: Data were collected from nine townships within Tshwane Metropolitan Municipality. Methods: The quantitative cross-sectional survey used the General Anxiety Disorder (GAD-7) tool to quantify anxiety symptoms, and a questionnaire was used to collect sociodemographic data from a sample of 390 participants. Results: The ages of the participants ranged from 18 years to 87 years, with a mean of 47 years. The mothers to the nyaope users were the biggest group at 35% (n = 138). The prevalence of anxiety symptoms was 73% (n = 286) of the total sample and ranged from mild (41.8, n = 163), moderate (14.62, n = 57) and severe (16.92%, n = 66). The Pearson chi-square test identified significant associations between anxiety symptoms and the gender of the participant (p = 0.001), the age of the nyaope user and the period of nyaope use (p = 0.008). Multivariate regression model indicated gender and place of residence as a significant variable in the development of anxiety symptoms (p = 0.01). Conclusion: Nyaope use is a risk factor for the development of anxiety for family members of nyaope users with the highest proportion reporting mild symptoms. Contribution: There is a need to develop interventions for mental health support for families of nyaope users.

The neutralization breadth of HIV-1 develops incrementally over four years and is associated with CD4+ T cell decline and high viral load during acute infection.

An understanding of how broadly neutralizing activity develops in HIV-1-infected individuals is needed to guide vaccine design and immunization strategies. Here we used a large panel of 44 HIV-1 envelope variants (subtypes A, B, and C) to evaluate the presence of broadly neutralizing antibodies in serum samples obtained 3 years after seroconversion from 40 women enrolled in the CAPRISA 002 acute infection cohort. Seven of 40 participants had serum antibodies that neutralized more than 40% of viruses tested and were considered to have neutralization breadth. Among the samples with breadth, CAP257 serum neutralized 82% (36/44 variants) of the panel, while CAP256 serum neutralized 77% (33/43 variants) of the panel. Analysis of longitudinal samples showed that breadth developed gradually starting from year 2, with the number of viruses neutralized as well as the antibody titer increasing over time. Interestingly, neutralization breadth peaked at 4 years postinfection, with no increase thereafter. The extent of cross-neutralizing activity correlated with CD4(+) T cell decline, viral load, and CD4(+) T cell count at 6 months postinfection but not at later time points, suggesting that early events set the stage for the development of breadth. However, in a multivariate analysis, CD4 decline was the major driver of this association, as viral load was not an independent predictor of breadth. Mapping of the epitopes targeted by cross-neutralizing antibodies revealed that in one individual these antibodies recognized the membrane-proximal external region (MPER), while in two other individuals, cross-neutralizing activity was adsorbed by monomeric gp120 and targeted epitopes that involved the N-linked glycan at position 332 in the C3 region. Serum antibodies from the other four participants targeted quaternary epitopes, at least 2 of which were PG9/16-like and depended on the N160 and/or L165 residue in the V2 region. These data indicate that fewer than 20% of HIV-1 subtype C-infected individuals develop antibodies with cross-neutralizing activity after 3 years of infection and that these antibodies target different regions of the HIV-1 envelope, including as yet uncharacterized epitopes.

Broad neutralization of human immunodeficiency virus type 1 mediated by plasma antibodies against the gp41 membrane proximal external region.

We identified three cross-neutralizing plasma samples with high-titer anti-membrane proximal external region (MPER) peptide binding antibodies from among 156 chronically human immunodeficiency virus type 1-infected individuals. In order to establish if these antibodies were directly responsible for the observed neutralization breadth, we used MPER-coated magnetic beads to deplete plasmas of these specific antibodies. Depletion of anti-MPER antibodies from BB34, CAP206, and SAC21 resulted in 77%, 68%, and 46% decreases, respectively, in the number of viruses neutralized. Antibodies eluted from the beads showed neutralization profiles similar to those of the original plasmas, with potencies comparable to those of the known anti-MPER monoclonal antibodies (MAbs), 4E10, 2F5, and Z13e1. The anti-MPER neutralizing antibodies in BB34 were present in the immunoglobulin G3 subclass-enriched fraction. Alanine scanning of the MPER showed that the antibodies from these three plasmas had specificities distinct from those of the known MAbs, requiring one to three crucial residues at positions 670, 673, and 674. These data demonstrate the existence of MPER-specific cross-neutralizing antibodies in plasma, although the ability to elicit such potent antiviral antibodies during natural infection appears to be rare. Nevertheless, the identification of three novel antibody specificities within the MPER supports its further study as a promising target for vaccine design.