PD-1 blockade potentiates HIV latency reversal ex vivo in CD4 T cells from ART-suppressed individuals.

HIV persists in latently infected CD4 T cells during antiretroviral therapy (ART). Immune checkpoint molecules, including PD-1, are preferentially expressed at the surface of persistently infected cells. However, whether PD-1 plays a functional role in HIV latency and reservoir persistence remains unknown.

CD4+ T Cells Expressing PD-1, TIGIT and LAG-3 Contribute to HIV Persistence during ART.

HIV persists in a small pool of latently infected cells despite antiretroviral therapy (ART). Identifying cellular markers expressed at the surface of these cells may lead to novel therapeutic strategies to reduce the size of the HIV reservoir. We hypothesized that CD4+ T cells expressing immune checkpoint molecules would be enriched in HIV-infected cells in individuals receiving suppressive ART.

A Higher Frequency of NKG2A+ than of NKG2A- NK Cells Responds to Autologous HIV-Infected CD4 Cells irrespective of Whether or Not They Coexpress KIR3DL1.

Unlabelled: Epidemiological and functional studies implicate NK cells in HIV control. However, there is little information available on which NK cell populations, as defined by the inhibitory NK cell receptors (iNKRs) they express, respond to autologous HIV-infected CD4(+) (iCD4) T cells. NK cells acquire antiviral functions through education, which requires signals received from iNKRs, such as NKG2A and KIR3DL1 (here, 3DL1), engaging their ligands.

Impaired Th17 polarization of phenotypically naive CD4(+) T-cells during chronic HIV-1 infection and potential restoration with early ART.

Background: Depletion of mucosal Th17 cells during HIV/SIV infections is a major cause for microbial translocation, chronic immune activation, and disease progression. Mechanisms contributing to Th17 deficit are not fully elucidated. Here we investigated alterations in the Th17 polarization potential of naive-like CD4(+) T-cells, depletion of Th17-commited subsets during HIV pathogenesis, and Th17 restoration in response to antiretroviral therapy (ART).

Nef promotes evasion of human immunodeficiency virus type 1-infected cells from the CTLA-4-mediated inhibition of T-cell activation.

CTLA-4 is a negative regulator of T-cell receptor-mediated CD4(+) T-cell activation and function. Upregulation of CTLA-4 during human immunodeficiency virus type 1 (HIV-1) infection on activated T cells, particularly on HIV-specific CD4(+) T cells, correlates with immune dysfunction and disease progression. As HIV-1 infects and replicates in activated CD4(+) T cells, we investigated mechanisms by which HIV-1 modulates CTLA-4 expression to establish productive viral infection in these cells.

Cross-clade ultrasensitive PCR-based assays to measure HIV persistence in large-cohort studies.

Unlabelled: A small pool of infected cells persists in HIV-infected individuals receiving antiretroviral therapy (ART). Here, we developed ultrasensitive assays to precisely measure the frequency of cells harboring total HIV DNA, integrated HIV DNA, and two long terminal repeat (2-LTR) circles. These assays are performed on cell lysates, which circumvents the labor-intensive step of DNA extraction, and rely on the coquantification of each HIV molecular form together with CD3 gene sequences to precisely measure cell input.

Transcriptional profiling reveals molecular signatures associated with HIV permissiveness in Th1Th17 cells and identifies peroxisome proliferator-activated receptor gamma as an intrinsic negative regulator of viral replication.

Background: We previously demonstrated that primary Th1Th17 cells are highly permissive to HIV-1, whereas Th1 cells are relatively resistant. Molecular mechanisms underlying these differences remain unknown.

Results: Exposure to replication competent and single-round VSV-G pseudotyped HIV strains provide evidence that superior HIV replication in Th1Th17 vs.

Interleukin-7 promotes HIV persistence during antiretroviral therapy.

HIV persists in latently infected memory CD4(+) T cells during antiretroviral therapy (ART). When administered to HIV-infected subjects receiving suppressive ART, interleukin-7 (IL-7) increases the number of CD4(+) T cells by promoting their survival and proliferation. However, little is known about the impact of IL-7 on HIV persistence during ART.

Foxo3a: an integrator of immune dysfunction during HIV infection.

Chronic HIV infection, which is primarily characterized by the progressive depletion of total CD4(+) T cells, also causes persistent inflammation and immune activation. This is followed by profound changes in cellular and tissue microenvironments that often lead to prolonged immune dysfunction. The global nature of this immune dysfunction suggests that factors that are involved in immune cell survival, proliferation, differentiation and maturation are all affected.

Characterization of a novel type of HIV-1 particle assembly inhibitor using a quantitative luciferase-Vpr packaging-based assay.

The HIV-1 auxiliary protein Vpr and Vpr-fusion proteins can be copackaged with Gag precursor (Pr55Gag) into virions or membrane-enveloped virus-like particles (VLP). Taking advantage of this property, we developed a simple and sensitive method to evaluate potential inhibitors of HIV-1 assembly in a living cell system. Two proteins were coexpressed in recombinant baculovirus-infected Sf9 cells, Pr55Gag, which formed the VLP backbone, and luciferase fused to the N-terminus of Vpr (LucVpr).

Loss of memory B cells during chronic HIV infection is driven by Foxo3a- and TRAIL-mediated apoptosis.

Loss of memory B cells occurs from the onset of HIV-1 infection and persists into the chronic stages of infection. Lack of survival of these cells, even in subjects being treated, could primarily be the consequence of an altered local microenvironment induced by HIV infection. In this study we showed that memory B cell survival was significantly decreased in aviremic successfully treated (ST) subjects compared with subjects who control viral load as a result of natural immunity (elite controller [EC]) or with uninfected control (HIV-) subjects.

Gold drug auranofin restricts the viral reservoir in the monkey AIDS model and induces containment of viral load following ART suspension.

Objectives: A small pool of long-lived memory CD4 T cells harboring the retroviral genome is one main obstacle to HIV eradication. We tested the impact of the gold compound, auranofin, on phenotype and viability of CD4 T cells in vitro, and on persistence of lentiviral reservoir cells in vivo.

Design: In-vitro and in-vivo study.

Maintenance of CD4+ T-cell memory and HIV persistence: keeping memory, keeping HIV.

Purpose Of Review: The present review summarizes the current challenges for the design of new therapeutic strategies toward HIV eradication in individuals receiving suppressive highly active antiretroviral therapy (HAART). We will focus on the experimental evidence suggesting that immunological mechanisms involved in the generation and maintenance of memory CD4+ T cells are also responsible for the establishment and persistence of a stable reservoir for HIV.

Recent Findings: Recent studies performed on clinical samples obtained from virally suppressed HIV-infected individuals indicate that T-cell survival and homeostatic proliferation, two major mechanisms involved in the maintenance of immunological memory, contribute to the persistence of latently infected memory CD4+ T cells.

The inhibition of assembly of HIV-1 virus-like particles by 3-O-(3',3'-dimethylsuccinyl) betulinic acid (DSB) is counteracted by Vif and requires its Zinc-binding domain.

Background: DSB, the 3-O-(3',3'dimethylsuccinyl) derivative of betulinic acid, blocks the last step of protease-mediated processing of HIV-1 Gag precursor (Pr55Gag), which leads to immature, noninfectious virions. When administered to Pr55Gag-expressing insect cells (Sf9), DSB inhibits the assembly and budding of membrane-enveloped virus-like particles (VLP). In order to explore the possibility that viral factors could modulate the susceptibility to DSB of the VLP assembly process, several viral proteins were coexpressed individually with Pr55Gag in DSB-treated cells, and VLP yields assayed in the extracellular medium.

The 3-O-(3',3'-dimethylsuccinyl) derivative of betulinic acid (DSB) inhibits the assembly of virus-like particles in HIV-1 Gag precursor-expressing cells.

Background: The 3-O-(3',3'-dimethylsuccinyl) derivative of betulinic acid (DSB) blocks HIV-1 maturation by interfering with viral protease (PR) at the capsid (CA)-SP1 cleavage site, a crucial region in HIV-1 morphogenesis.

Methods: We analysed the effect of DSB on the assembly of HIV-1 Gag precursor (Pr55Gag(HIV)) into membrane-enveloped virus-like particles (VLP) in baculovirus-infected cells expressing Pr55Gag(HIV), in a cellular context devoid of viral PR.

Results: DSB showed a dose-dependent negative effect on VLP assembly, with an IC50 approximately 10 microM.