Inhibition of HIV virus by neutralizing Vhh attached to dual functional liposomes encapsulating dapivirine

Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations

P12-11. Resistance to the CD4 mimetic mini protein M48-U1 induces changes in a highly conserved region on the HIV-1 gp120 envelope protein

International audienc

P18-08. Characterization of CD34+ derived dendritic cells generated in vitro and transfected with HIV gene as potential therapeutic vaccine in macaque

International audiencen.

CD32+CD4+memory T cells are enriched for total HIV-1 DNA in tissues from humanized mice

CD32 has raised conflicting results as a putative marker of the HIV-1 reservoir. We measured CD32 expression in tissues from viremic and virally suppressed humanized mice treated relatively early or late after HIV-1 infection with combined antiretroviral therapy. CD32 was expressed in a small fraction of the memory CD4(+) T-cell subsets from different tissues in viremic and aviremic mice, regardless of treatment initiation time. CD32(+) memory CD4(+) T cells were enriched in cell associated (CA) HIV-1 DNA but not in CA HIV-1 RNA as compared to the CD32(-) CD4(+) fraction. Using multidimensional reduction analysis, several memory CD4(+)CD32(+) T-cell clusters were identified expressing HLA-DR, TIGIT, or PD-1. Importantly, although tissue-resident CD32(+)CD4(+) memory cells were enriched with translation-competent reservoirs, most of it was detected in memory CD32-CD4(+) T cells. Our findings support that CD32 labels highly activated/exhausted memory CD4(+) T-cell subsets that contain only a small proportion of the translation-competent reservoir

A longitudinal analysis of the vaginal microbiota and vaginal immune mediators in women from sub-Saharan Africa

In cross-sectional studies increased vaginal bacterial diversity has been associated with vaginal inflammation which can be detrimental for health. We describe longitudinal changes at 5 visits over 8 weeks in vaginal microbiota and immune mediators in African women. Women (N = 40) with a normal Nugent score at all visits had a stable lactobacilli dominated microbiota with prevailing Lactobacillus iners. Presence of prostate-specific antigen (proxy for recent sex) and being amenorrhoeic (due to progestin-injectable use), but not recent vaginal cleansing, were significantly associated with microbiota diversity and inflammation (controlled for menstrual cycle and other confounders). Women (N = 40) with incident bacterial vaginosis (Nugent 7-10) had significantly lower concentrations of lactobacilli and higher concentrations of Gardnerella vaginalis, Atopobium vaginae, and Prevotella bivia, at the incident visit and when concentrations of proinflammatory cytokines (IL-1β, IL-12p70) were increased and IP-10 and elafin were decreased. A higher 'composite-qPCR vaginal-health-score' was directly associated with decreased concentrations of proinflammatory cytokines (IL-1α, IL-8, IL-12(p70)) and increased IP-10. This longitudinal study confirms the inflammatory nature of vaginal dysbiosis and its association with recent vaginal sex and progestin-injectable use. A potential role for proinflammatory mediators and IP-10 in combination with the vaginal-health-score as predictive biomarkers for vaginal dysbiosis merits further investigation

Nef interferes with development of thymic T cell precursors: differential mechanisms in HIV and SIV

BioMed Central Open acces