Polyfunctional Hiv-Specific Antibody Responses Are Associated with Spontaneous Hiv Control

Elite controllers (ECs) represent a unique model of a functional cure for HIV-1 infection as these individuals develop HIV-specific immunity able to persistently suppress viremia. Because accumulating evidence suggests that HIV controllers generate antibodies with enhanced capacity to drive antibody-dependent cellular cytotoxicity (ADCC) that may contribute to viral containment, we profiled an array of extra-neutralizing antibody effector functions across HIV-infected populations with varying degrees of viral control to define the characteristics of antibodies associated with spontaneous control. While neither the overall magnitude of antibody titer nor individual effector functions were increased in ECs, a more functionally coordinated innate immune–recruiting response was observed. Specifically, ECs demonstrated polyfunctional humoral immune responses able to coordinately recruit ADCC, other NK functions, monocyte and neutrophil phagocytosis, and complement. This functionally coordinated response was associated with qualitatively superior IgG3/IgG1 responses, whereas HIV-specific IgG2/IgG4 responses, prevalent among viremic subjects, were associated with poorer overall antibody activity. Rather than linking viral control to any single activity, this study highlights the critical nature of functionally coordinated antibodies in HIV control and associates this polyfunctionality with preferential induction of potent antibody subclasses, supporting coordinated antibody activity as a goal in strategies directed at an HIV-1 functional cure

Characterization of a Novel Dendritic Cell Population

Conventional DC (cDC) arise from circulating immediate precursors (pre-cDC), and are currently thought to be terminally differentiated. Here we show that cDC are capable of generating progeny that lost all characteristic features of cDC and aquired regulatory properties. Sorted bone marrow pre-cDCs were cultured on a stromal monolayer in the presence or absence of granulocyte-macrophage colony stimulating factor (GM-CSF). In the absence of GM-CSF, pre-cDC derived DCs gave rise to a homogeneous population of CD11clow MHClow cells (DC-regs) on day 8-10 of culture. DC-regs failed to up-regulate major histocompatibility complex class II (MHCII) and co-stimulatory molecules in response to DC maturation stimuli, were poor stimulators in T cell proliferation assays and suppressed T cell proliferation in cultures containing immuno-stimulatory DC. Co-transfer of DC-regs with DCs in vivo did not inhibit proliferation of T cells. These findings reveal the potential of DCs to generate a regulatory DC population with immunosuppressive properties.MAS

[Les peptides dérivés de l'AAC-11 antagonisent la survie et l'infection des cellules T CD4 + et des macrophages sensibles au VIH-1]

Despite its discovery more than 30 years ago, HIV epidemic remains one of the global health challenges of today. Among many important questions remaining is how does HIV-1 successfully establish infection and persist in its reservoirs despite viral cytotoxic effect observed both in vitro and in vivo? This work shows that HIV-1 relies on AAC-11 anti- apoptotic pathway for the establishment of productive infection in CD4+ T cells and macrophages, primary targets of HIV-1. We observed the expression of AAC-11 to increase with progressive CD4+ memory T cell differentiation and to associate with the expression of cell cycle, activation and metabolism genes, known factors for HIV-1 susceptibility. Antagonism of AAC-11 survival pathway with the peptides derived from its sequence lead to cell death of HIV-1 susceptible target cells and resistance of surviving cells to infection. The peptides caused preferential elimination of effector and transitional CD4+ T cell memory subsets as well as highly activated and metabolically active cells, and their activity was at least in part dependent on caspase 2 activation. Thus, our results provide a proof of concept that the selective targeting of the survival pathways used by HIV-1 is a possible approach to antagonize the seeding of HIV-1 CD4+ T cell and macrophage reservoirs.Malgré plus de 30 ans de recherche intensive depuis le début de l’épidémie, le virus de l’immunodéficience humaine (VIH) reste l’un des plus gros problème de santé publique. L’une des problématiques les plus importantes empêchant le progrès vers la résolution de combat avec cette maladie reste de comprendre comment le VIH de type 1 établie l’infection et la persistance dans ses réservoirs. Et ce, malgré l’effet cytotoxique du virus qui est observé in vitro et in vivo. Ce travail montre que le VIH-1 dépend de la voie de signalisation anti-apoptotique d’AAC-11 pour établir l’infection dans les lymphocytes CD4+ T et les macrophages qui sont les cibles importantes du VIH-1. Nous observons que l’expression d’AAC-11 augmente avec la différentiation des lymphocytes CD4+ T mémoires. Nous avons également remarqué que l’expression d’AAC-11 est associée avec l’expression des gènes du cycle cellulaire, de l’activation et du métabolisme, des facteurs qui jouent un rôle dans la susceptibilité du VIH-1. Nous avons modulé la voie de signalisation d’AAC-11 avec l’antagonisme provenant des peptides dérivés de sa séquence et observé la mort cellulaire des cellules susceptibles à l’infection. Nous avons également observé que les cellules restantes étaient résistantes à l’infection. Les peptides ont éliminé préférablement les cellules effectrices et transitionnelles mémoires CD4+ T, ainsi que les cellules activées et métaboliquement actives. Leur activité était en partie dépendant de l’activation de caspase-2. Par conséquent, nos résultats présentent une preuve de concept que le ciblage des voies de survie cellulaires utilisées par le VIH est une approche plausible pour impacter négativement l’ensemencement du réservoir de VIH, dont font parties les cellules CD4+ T et macrophages

Anti-apoptotic clone 11 derived peptides induce in vitro death of CD4+ T cells susceptible to HIV-1 infection

International audienceHIV-1 successfully establishes long-term infection in its target cells despite viral cytotoxic effects. We have recently shown that cell metabolism is an important factor driving CD4+ T-cell susceptibility to HIV-1 and the survival of infected cells. We show here that expression of anti-apoptotic clone 11 (AAC-11), an anti-apoptotic factor upregulated in many cancers, increased with progressive CD4+ T cell memory differentiation in association with the expression of cell cycle, activation and metabolism genes and correlated with susceptibility to HIV-1 infection. Synthetic peptides based on the LZ domain sequence of AAC-11, responsible for its interaction with molecular partners, were previously shown to be cytotoxic to cancer cells. Here we observed that these peptides also blocked HIV-1 infection by inducing cell death of HIV-1 susceptible primary CD4+ T-cells across all T-cell subsets. The peptides targeted metabolically active cells and had the greatest effect on effector and transitional CD4+ T cell memory subsets. Our results suggest that AAC-11 survival pathway is potentially involved in the survival of HIV-1 infectable cells and provide a proof of principle that some cellular characteristics can be targeted to eliminate the cells offering the best conditions to sustain HIV-1 replication.IMPORTANCE Although antiretroviral treatment efficiently blocks HIV multiplication, it cannot eliminate the cells already carrying integrated proviruses. In the search for a HIV cure the identification of new potential targets to selectively eliminate infected cells is of the outmost importance. We show here that peptides derived from the anti-apoptotic clone 11 (AAC-11), which expression levels correlated with susceptibility to HIV-1 infection of CD4+ T-cells, induced cytotoxicity in CD4+ T-cells showing the highest levels of activation and metabolic activity, conditions known to favor HIV-1 infection. Accordingly, CD4+ T-cells that survived the cytotoxic action of the AAC-11 peptides were resistant to HIV-1 replication. Our results identify a new potential molecular pathway to target HIV-1 infection

High‐resolution definition of humoral immune response correlates of effective immunity against HIV

Abstract Defining correlates of immunity by comprehensively interrogating the extensive biological diversity in naturally or experimentally protected subjects may provide insights critical for guiding the development of effective vaccines and antibody‐based therapies. We report advances in a humoral immunoprofiling approach and its application to elucidate hallmarks of effective HIV‐1 viral control. Systematic serological analysis for a cohort of HIV‐infected subjects with varying viral control was conducted using both a high‐resolution, high‐throughput biophysical antibody profiling approach, providing unbiased dissection of the humoral response, along with functional antibody assays, characterizing antibody‐directed effector functions such as complement fixation and phagocytosis that are central to protective immunity. Profiles of subjects with varying viral control were computationally analyzed and modeled in order to deconvolute relationships among IgG Fab properties, Fc characteristics, and effector functions and to identify humoral correlates of potent antiviral antibody‐directed effector activity and effective viral suppression. The resulting models reveal multifaceted and coordinated contributions of polyclonal antibodies to diverse antiviral responses, and suggest key biophysical features predictive of viral control

Shigella impairs human T lymphocyte responsiveness by hijacking actin cytoskeleton dynamics and T cell receptor vesicular trafficking

International audienceStrategies employed by pathogenic enteric bacteria, such as Shigella, to subvert the host adaptive immunity are not well defined. Impairment of T lymphocyte chemotaxis by blockage of polarised edge formation has been reported upon Shigella infection. However, the functional impact of Shigella on T lymphocytes remains to be determined. Here, we show that Shigella modulates CD4+ T cell F-actin dynamics and increases cell cortical stiffness. The scanning ability of T lymphocytes when encountering antigen-presenting cells (APC) is subsequently impaired resulting in decreased cell-cell contacts (or conjugates) between the two cell types, as compared with non-infected T cells. In addition, the few conjugates established between the invaded T cells and APCs display no polarised delivery and accumulation of the T cell receptor to the contact zone characterising canonical immunological synapses. This is most likely due to the targeting of intracellular vesicular trafficking by the bacterial type III secretion system (T3SS) effectors IpaJ and VirA. The collective impact of these cellular reshapings by Shigella eventually results in T cell activation dampening. Altogether, these results highlight the combined action of T3SS effectors leading to T cell defects upon Shigella infection

Functional coordination within HIV-infected subject groups.

<p><b>A.</b> The extent of functional coordination within groups was assessed by calculating Spearman’s rank correlation coefficients across each pair of independently assessed functional assays. Differences between subject groups were evaluated using a Friedman ANOVA corrected for multiple comparisons using Dunn’s Test in Graphpad Prism. <b>B</b>. Prevalence of functional correlations by strength for each subject group. <b>C</b>. Correlation matrix for each pairwise combination of functions tested, in which strong positive correlations appear blue while inverse correlations appear red, for each subject group. Correlative relationships and significance were calculated and visualized using R, with unadjusted p values indicated to facilitate relative comparisons.</p

Levels and IgG subclass composition differentiate HIV+ subject groups.

<p><b>A.</b> Titer (Mean Fluorescent Intensity, MFI) of gp120-specific IgG present in each subject group. <b>B</b>. The percent of subjects in each group positive for gp120-specific responses of each IgG subclass. <b>C.</b> Spearman correlation matrix between subclass responses across subjects. Strength and significance, as calculated in Graphpad Prism, are represented as color intensity and size, respectively. <b>D.</b> The levels of gp120-specific responses observed across cohort groups for each IgG subclass. Differences between groups were assessed by Kruskal-Wallis ANOVA and corrected for multiple comparisons using Dunn’s test in Graphpad Prism.</p

Antibody functionality can be predicted by subclass composition.

<p><b>A</b>. Correlative relationships between levels of total gp120-specific IgG or gp120-specific antibodies of each subclass to antibody function were assessed by determination of Spearman’s rank correlation coefficients between activity and antibody MFI within each subject group. <b>B</b>. Correlative relationships between <i>relative</i> levels of gp120-specific antibodies of each subclass (i.e., MFI of subclass/MFI of total IgG) were assessed for each functional activity, over all subjects. Positive associations are noted in blue and inverse associations in red, with the magnitude of correlation depicted by intensity. Correlative relationships and significance were calculated and visualized using R, with unadjusted p values indicated to facilitate relative comparisons. <b>C</b>. The magnitude and direction of the contribution of SF162-specific antibody subclass assessments to cross-validated predictive models of polyfunctional activity.</p

Cellular Metabolism Is a Major Determinant of HIV-1 Reservoir Seeding in CD4+ T Cells and Offers an Opportunity to Tackle Infection.

International audienceHIV persists in long-lived infected cells that are not affected by antiretroviral treatment. These HIV reservoirs are mainly located in CD4+ T cells, but their distribution is variable in the different subsets. Susceptibility to HIV-1 increases with CD4+ T cell differentiation. We evaluated whether the metabolic programming that supports the differentiation and function of CD4+ T cells affected their susceptibility to HIV-1. We found that differences in HIV-1 susceptibility between naive and more differentiated subsets were associated with the metabolic activity of the cells. Indeed, HIV-1 selectively infected CD4+ T cells with high oxidative phosphorylation and glycolysis, independent of their activation phenotype. Moreover, partial inhibition of glycolysis (1) impaired HIV-1 infection in vitro in all CD4+ T cell subsets, (2) decreased the viability of preinfected cells, and (3) precluded HIV-1 amplification in cells from HIV-infected individuals. Our results elucidate the link between cell metabolism and HIV-1 infection and identify a vulnerability in tackling HIV reservoirs