Project description:Without treatment, HIV-1 infection is characterized in the majority of individuals by a detectable HIV replication and a rapid decline in CD4+ T lymphocytes leading to AIDS. However, a minority of patients, called “HIV Controllers” (HIC), maintains spontaneous control of HIV replication and for a large part, normal CD4+ T cell counts. The mechanisms leading to this spontaneous virus control are not fully known. We used gene expression and functional cellular analyses to compare EC and chronically HIV-1 infected individuals with controlled virus replication under combined antiretroviral therapy (cART). In the blood, EC individuals are characterized by a low inflammation, a down modulation of NK inhibitory cell signaling and an up regulation of T-cell activation gene expression profiles. Interestingly, in contrast to cART individuals, this balance persists following in vitro stimulation of cells from HIC with HIV antigens. This favourable genetic profile in HIC was also consistent with functional analyses showing a bias towards a Th1 and cytotoxic T cell profile and a lower production of inflammatory cytokines. Finally, taking advantage of the characterization of HIC based upon their in vitro CD8+ T lymphocyte capacity of killing HIV-infected cells, we show that unsupervised genetic analysis of differentially expressed genes fits clearly with this cytotoxic activity allowing the characterization of a specific signature of HIC individuals. Globally, these results reveal significant features of HIC making the bridge between cellular function and gene signatures and the regulation of inflammation and killing capacity of HIV-specific CD8+T cells. Moreover, these genetic profiles are consistent through analyses performed from whole blood to PBMC and at the T-cell population levels. Likely, these data help to define the goals of immunotherapeutic approaches in the perspective of HIV-1 functional cure. These strategies would need to induce both strong HIV-1-specific immune responses whereas minimizing inflammation.

Project description:Antiretroviral therapy (ART) has the potency of suppressing systemic viral replication and spread. Still, persistent human immunodeficiency virus type-1 (HIV) survive for decades during treatment in latently infected cells, making up the latent viral reservoir. This reservoir is believed to reside in subtypes of memory T cells and cell from monocytic lineages, but some functional and naïve T cells have also shown to carry latent HIV. Eradication of latently infected cells, in terms of a sterilizing cure, have proven to be a hurdle since there is a heterogeneity in mechanisms governing latency and integration site into the genome. Over the course of suppressive therapy, persisting HIV, sustained by low levels of viral replication, homeostatic proliferation, and cell to cell transmission, is a driver of chronic immune activation in the body. For the immune system to elicit an appropriate inflammatory response it is dependent on secretion of inflammatory molecules, such as chemokines and cytokines. Most chemokines are pro-inflammatory factors that facilitate leukocyte recruitment to site of inflammation where they can exert their regulatory role in response to pathological and physiological stressors e.g., infection, inflammation, and tissue damage. Alterations in chemokine receptor expression and chemokine levels modulates the activity of the immune response and in HIV infection contribute to chronic inflammation and mortality. Therefore, people living with HIV on suppressive therapy (PLWH) are at higher risk of age associated co-morbidities due to elevated immune activation and chronic inflammation induced by ART toxicities, microbiome dysbiosis leading to microbial translocation and dysregulated immune cell activation and function. As a result, the causative HIV pathogenesis and immune dysfunction further chronic immune activation. This result in a vicious cycle as immune activation is driver of HIV disease progression and inflammaeging leading to earlier onset of age-related diseases. An alternative approach in cure strategies is a functional cure for HIV aiming at suppressing viral replication without ART. A model for functional cure studies are elite controllers (EC). EC constitute a small fraction of HIV+ individuals (<0.5%) exhibiting the unique characteristic of natural control of viral replication in absence of ART. However, there is a population-based heterogeneity of how these individuals naturally supress viral replication. This heterogeneity is caused by viral genetic factors, variability of integration site in the human genome, together with host response against the pathogen and immunological factors. In terms of immune cell activation, studies have shown how EC maintain lower levels of inflammatory markers compared to PLWH. Contradictory, some studies have shown elevated inflammatory markers in EC which could be attributed to the heterogeneity of the EC group or as others have shown it is a consequence of loss of spontaneous control of HIV. Therefore, as no consensus exist further studies comparing variability of immune function between EC and ART can aid in understanding the mechanisms of natural control of HIV. In our recent study (Sperk et al 2021, iScience) we hypothesised that modulated CCR6/CCL20 chemokine axis and CCR2-CCL7-CCL2 signalling can play a protective role in the EC phenotype. Downregulation of CCR2 and CCR6 receptors in lymphocytes and higher plasma abundance of CCL4, CCL7 and CCL20 in EC compared to the HIV-negative controls can provide natural resistance to HIV-infection. In the present study, we further extended our analysis to evaluate the expression profile dynamics of key chemokine receptors, CCR2, CCR3, CCR5 and CCR6, in successfully treated PLWH. We compared well treated PLWH with HIV-1 elite controllers and its association with HIV-1 persistence. Furthermore, cell populations of interest were isolated for liquid chromatography mass spectrometry (LC-MS/MS) based untargeted proteomics analysis to evaluate specific characteristics regulating these cell populations and their role in HIV persistence. Our study provides important understanding of the chemokine receptor dynamics and its role in HIV persistence that differentiate elite controllers from long term treated PLWH.

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Integrative genomic and cellular analyses of blood and T cells from HIV-1 controllers reveal a low inflammatory profile associated with strong HIV-specific adaptive responses [PBMC]

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