Pegylated Interferon-α-Induced Natural Killer Cell Activation Is Associated With Human Immunodeficiency Virus-1 DNA Decline in Antiretroviral Therapy-Treated HIV-1/Hepatitis C Virus-Coinfected Patients

Differential susceptibility of cells infected with defective and intact HIV proviruses to killing by obatoclax and other small molecules

OBJECTIVES

Some drugs that augment cell-intrinsic defenses or modulate cell death/survival pathways have been reported to selectively kill cells infected with HIV or Simian Immunodeficiency Virus (SIV), but comparative studies are lacking. We hypothesized that these drugs may differ in their ability to kill cells infected with intact and defective proviruses.

DESIGN

To investigate this hypothesis, drugs were tested ex vivo on peripheral blood mononuclear cells (PBMC) from nine antiretroviral therapy (ART)-suppressed individuals.

METHODS

We tested drugs currently in clinical use or human trials, including auranofin (p53 modulator), interferon alpha2A, interferon gamma, acitretin (RIG-I inducer), GS-9620/vesatolimod (TLR7 agonist), nivolumab (PD-1 blocker), obatoclax (Bcl-2 inhibitor), birinapant [inhibitor of apoptosis proteins (IAP) inhibitor], bortezomib (proteasome inhibitor), and INK128/sapanisertib [mammalian target of rapamycin mTOR] [c]1/2 inhibitor). After 6 days of treatment, we measured cell counts/viabilities and quantified levels of total, intact, and defective HIV DNA by droplet digital PCR (Intact Proviral DNA Assay).

RESULTS

Obatoclax reduced intact HIV DNA [median = 27-30% of dimethyl sulfoxide control (DMSO)] but not defective or total HIV DNA. Other drugs showed no statistically significant effects.

CONCLUSION

Obatoclax and other Bcl-2 inhibitors deserve further study in combination therapies aimed at reducing the intact HIV reservoir in order to achieve a functional cure and/or reduce HIV-associated immune activation.

Immune targeting of HIV-1 reservoir cells: a path to elimination strategies and cure

Successful approaches for eradication or cure of HIV-1 infection are likely to include immunological mechanisms, but remarkably little is known about how human immune responses can recognize and interact with the few HIV-1-infected cells that harbour genome-intact viral DNA, persist long term despite antiretroviral therapy and represent the main barrier to a cure. For a long time regarded as being completely shielded from host immune responses due to viral latency, these cells do, on closer examination with single-cell analytic techniques, display discrete footprints of immune selection, implying that human immune responses may be able to effectively engage and target at least some of these cells. The failure to eliminate rebound-competent virally infected cells in the majority of persons likely reflects the evolution of a highly selected pool of reservoir cells that are effectively camouflaged from immune recognition or rely on sophisticated approaches for resisting immune-mediated killing. Understanding the fine-tuned interplay between host immune responses and viral reservoir cells will help to design improved interventions that exploit the immunological vulnerabilities of HIV-1 reservoir cells.

Kombucha as a Health-Beneficial Drink for Human Health

Kombucha is a unique fermented beverage made from a symbiotic culture of yeast and bacteria. Kombucha is normally based on black tea added to water, then sugar is added as a substrate for fermentation in this beverage. This unique beverage is composed of amino acids, flavonoids, vitamins, and some active enzymes. Several beneficial health effects such as antioxidant, antimicrobial effects have been reported as a result of probiotics and prebiotics presence. These health effects of kombucha are attributed to its bioactive chemical and biological agents of probiotics bacteria e.g., Gluconobacter, Acetobacter and yeasts like Saccharomyces sps., along with glucuronic acid as the main sources of the health protection. This review focuses on the beneficial effects of Kombucha including antimicrobial, antioxidant, anti-cancer antidiabetic properties, as well as liver protection, treat of gastrointestinal problems, AIDS, gastric ulcers, obesity (and energy production), detoxification, and skin health.

Harnessing natural killer cells to target HIV-1 persistence

PURPOSE OF REVIEW

The purpose of this article is to review recent advances in the role of natural killer (NK) cells in approaches aimed at reducing the latent HIV-1 reservoir.

RECENT FINDINGS

Multiple approaches to eliminate cells harboring latent HIV-1 are being explored, but have been met with limited success so far. Recent studies have highlighted the role of NK cells and their potential in HIV-1 cure efforts. Anti-HIV-1 NK cell function can be optimized by enhancing NK cell activation, antibody dependent cellular cytotoxicity, reversing inhibition of NK cells as well as by employing immunotherapeutic complexes to enable HIV-1 specificity of NK cells. While NK cells alone do not eliminate the HIV-1 reservoir, boosting NK cell function might complement other strategies involving T cell and B cell immunity towards an HIV-1 functional cure.

SUMMARY

Numerous studies focusing on targeting latently HIV-1-infected cells have emphasized a potential role of NK cells in these strategies. Our review highlights recent advances in harnessing NK cells in conjunction with latency reversal agents and other immunomodulatory therapeutics to target HIV-1 persistence.

Selection of epigenetically privileged HIV-1 proviruses during treatment with panobinostat and interferon-α2a

CD4+ T cells with latent HIV-1 infection persist despite treatment with antiretroviral agents and represent the main barrier to a cure of HIV-1 infection. Pharmacological disruption of viral latency may expose HIV-1-infected cells to host immune activity, but the clinical efficacy of latency-reversing agents for reducing HIV-1 persistence remains to be proven. Here, we show in a randomized-controlled human clinical trial that the histone deacetylase inhibitor panobinostat, when administered in combination with pegylated interferon-α2a, induces a structural transformation of the HIV-1 reservoir cell pool, characterized by a disproportionate overrepresentation of HIV-1 proviruses integrated in ZNF genes and in chromatin regions with reduced H3K27ac marks, the molecular target sites for panobinostat. By contrast, proviruses near H3K27ac marks were actively selected against, likely due to increased susceptibility to panobinostat. These data suggest that latency-reversing treatment can increase the immunological vulnerability of HIV-1 reservoir cells and accelerate the selection of epigenetically privileged HIV-1 proviruses.

Next-generation bNAbs for HIV-1 cure strategies

Despite the ability to suppress viral replication using anti-retroviral therapy (ART), HIV-1 remains a global public health problem. Curative strategies for HIV-1 have to target and eradicate latently infected cells across the body, i.e. the viral reservoir. Broadly neutralizing antibodies (bNAbs) targeting the HIV-1 envelope glycoprotein (Env) have the capacity to neutralize virions and bind to infected cells to initiate elimination of these cells. To improve the efficacy of bNAbs in terms of viral suppression and viral reservoir eradication, next generation antibodies (Abs) are being developed that address the current limitations of Ab treatment efficacy; (1) low antigen (Env) density on (reactivated) HIV-1 infected cells, (2) high viral genetic diversity, (3) exhaustion of immune cells and (4) short half-life of Abs. In this review we summarize and discuss preclinical and clinical studies in which anti-HIV-1 Abs demonstrated potent viral control, and describe the development of engineered Abs that could address the limitations described above. Next generation Abs with optimized effector function, avidity, effector cell recruitment and immune cell activation have the potential to contribute to an HIV-1 cure or durable control.

Mechanisms underlying HIV-associated cognitive impairment and emerging therapies for its management

People living with HIV are affected by the chronic consequences of neurocognitive impairment (NCI) despite antiretroviral therapies that suppress viral replication, improve health and extend life. Furthermore, viral suppression does not eliminate the virus, and remaining infected cells may continue to produce viral proteins that trigger neurodegeneration. Comorbidities such as diabetes mellitus are likely to contribute substantially to CNS injury in people living with HIV, and some components of antiretroviral therapy exert undesirable side effects on the nervous system. No treatment for HIV-associated NCI has been approved by the European Medicines Agency or the US Food and Drug Administration. Historically, roadblocks to developing effective treatments have included a limited understanding of the pathophysiology of HIV-associated NCI and heterogeneity in its clinical manifestations. This heterogeneity might reflect multiple underlying causes that differ among individuals, rather than a single unifying neuropathogenesis. Despite these complexities, accelerating discoveries in HIV neuropathogenesis are yielding potentially druggable targets, including excessive immune activation, metabolic alterations culminating in mitochondrial dysfunction, dysregulation of metal ion homeostasis and lysosomal function, and microbiome alterations. In addition to drug treatments, we also highlight the importance of non-pharmacological interventions. By revisiting mechanisms implicated in NCI and potential interventions addressing these mechanisms, we hope to supply reasons for optimism in people living with HIV affected by NCI and their care providers.

Natural killer cells during acute HIV-1 infection: clues for HIV-1 prevention and therapy

Despite progress in preexposure prophylaxis, the number of newly diagnosed cases with HIV-1 remains high, highlighting the urgent need for preventive and therapeutic strategies to reduce HIV-1 acquisition and limit disease progression. Early immunological events, occurring during acute infection, are key determinants of the outcome and course of disease. Understanding early immune responses occurring before viral set-point is established, is critical to identify potential targets for prophylactic and therapeutic approaches. Natural killer (NK) cells represent a key cellular component of innate immunity and contribute to the early host defence against HIV-1 infection, modulating the pathogenesis of acute HIV-1 infection (AHI). Emerging studies have identified tools for harnessing NK cell responses and expanding specialized NK subpopulations with adaptive/memory features, paving the way for development of novel HIV-1 therapeutics. This review highlights the knowns and unknowns regarding the role of NK cell subsets in the containment of acute HIV-1 infection, and summarizes recent advances in selectively augmenting NK cell functions through prophylactic and therapeutic interventions.

Engaging innate immunity in HIV-1 cure strategies

Combination antiretroviral therapy (ART) can block multiple stages of the HIV-1 life cycle to prevent progression to AIDS in people living with HIV-1. However, owing to the persistence of a reservoir of latently infected CD4⁺ T cells, life-long ART is necessary to prevent viral rebound. One strategy currently under consideration for curing HIV-1 infection is known as 'shock and kill'. This strategy uses latency-reversing agents to induce expression of HIV-1 genes, allowing for infected cells to be cleared by cytolytic immune cells. The role of innate immunity in HIV-1 pathogenesis is best understood in the context of acute infection. Here, we suggest that innate immunity can also be used to improve the efficacy of HIV-1 cure strategies, with a particular focus on dendritic cells (DCs) and natural killer cells. We discuss novel latency-reversing agents targeting DCs as well as DC-based strategies to enhance the clearance of infected cells by CD8⁺ T cells and strategies to improve the killing activity of natural killer cells.

Targeting NK Cells for HIV-1 Treatment and Reservoir Clearance

Combined antiretroviral therapy (cART) can inhibit the replication of human immunodeficiency virus type 1 (HIV-1) and reduce viral loads in the peripheral blood to undetectable levels. However, the presence of latent HIV-1 reservoirs prevents complete HIV-1 eradication. Several drugs and strategies targeting T cells are now in clinical trials, but their effectiveness in reducing viral reservoirs has been mixed. Interestingly, innate immune natural killer (NK) cells, which are promising targets for cancer therapy, also play an important role in HIV-1 infection. NK cells are a unique innate cell population with features of adaptive immunity that can regulate adaptive and innate immune cell populations; therefore, they can be exploited for HIV-1 immunotherapy and reservoir eradication. In this review, we highlight immunotherapy strategies for HIV infection that utilize the beneficial properties of NK cells.

HIV-reservoir size is not affected either by HCV coinfection or by direct acting antivirals (DAAs) therapy

The role of HCV on the HIV reservoir is controversial since the reduction on HIV-DNA levels after HCV eradication with IFNα/RBV treatment seems to be the result of drugs instead of HCV clearance. We assessed whether HCV eradication can decrease HIV-DNA content in HIV/HCV-coinfected patients treated with direct-acting antivirals, DAAs (IFNα/RBV-free regimens). Cell-associated HIV-DNA was measured by ddPCR in 25 HIV-monoinfected and 25 HIV/HCV-coinfected patients. There were no differences in HIV-DNA levels between groups neither at baseline nor at 12 weeks after DAAs treatment completion. Our results indicate that HCV does not appear to influence the HIV reservoir size and suggest the lack of an anti-HIV action for DAAs.

Negative Regulation and Protective Function of Natural Killer Cells in HIV Infection: Two Sides of a Coin

Natural killer (NK) cells play an important immunologic role, targeting tumors and virus-infected cells; however, NK cells do not impede the progression of human immunodeficiency virus (HIV) infection. In HIV infection, NK cells exhibit impaired functions and negatively regulate other immune cell responses, although NK cells can kill HIV-infected cells and thereby suppress HIV replication. Considerable recent research has emerged regarding NK cells in the areas of immune checkpoints, negative regulation, antibody-dependent cell-mediated cytotoxicity and HIV reservoirs during HIV infection; however, no overall summary of these factors is available. This review focuses on several important aspects of NK cells in relation to HIV infection, including changes in NK cell count, subpopulations, and immune checkpoints, as well as abnormalities in NK cell functions and NK cell negative regulation. The protective function of NK cells in inhibiting HIV replication to reduce the viral reservoir and approaches for enhancing NK cell functions are also summarized.

Distinct effects of treatment with two different interferon-alpha subtypes on HIV-1-associated T-cell activation and dysfunction in humanized mice

OBJECTIVE

Interferon-alpha (IFN-α) has been associated with excessive immune activation and dysfunction during HIV-1 infection. However, evidence suggests specific IFN-α subtypes may be beneficial rather than detrimental. This study compared the effects of treatment with two different IFN-α subtypes on indicators of T-cell activation and dysfunction during HIV-1 infection.

DESIGN

Humanized mice were infected with HIV-1 for 5 weeks and then treated with two different IFN-α subtypes for an additional 3 weeks. Splenic T cells were assessed both immediately posttreatment and again 6 weeks after treatment cessation.

METHODS

HIV-1 infected triple-knockout bone marrow-liver-thymus mice received daily intraperitoneal injections of either IFN-α14 or the clinically approved subtype, IFN-α2. T cells were analysed directly ex vivo for indicators of activation and dysfunction or stimulated to determine their proliferative capacity and ability to produce functional mediators.

RESULTS

Unlike IFN-α2, IFN-α14 treatment reduced viremia and resulted in less activated CD4+ T cells and a lower naïve to effector CD8+ T-cell ratio. Despite exhibiting a reduced proliferative response, the frequency of CD8+ T cells from IFN-α14 treated mice that produced functional mediators and expressed markers of dysfunction was more similar to healthy controls than untreated and IFN-α2 treated mice. Frequencies of exhaustion marker expression remained higher in untreated and IFN-α2 treated mice 6 weeks posttreatment despite similar viral loads between groups at this timepoint.

CONCLUSIONS

Treatment with different IFN-α subtypes had distinctive effects on T cells during HIV-1 infection. IFN-α14 was associated with fewer indicators of T-cell dysfunction whereas IFN-α2 treatment had little impact.

Changes in NK Cell Subsets and Receptor Expressions in HIV-1 Infected Chronic Patients and HIV Controllers

Natural killer (NK) cells are major effectors of the innate immune response and purported to play an influential role in the spontaneous control of HIV infection. In the present study, we compared the phenotypes of NK cells in the peripheral blood of three groups of subjects with chronic HIV-1 infection, HIV controllers, and healthy donors. The results showed that CD56⁺/CD16^- NK cell subsets decreased in chronic patients and remained unchanged in controllers. Notably, we found that people living with chronic HIV-1 infection had suppressed NKp80, NKp46, and NKG2D expressions on NK cells compared to healthy donors, while HIV controllers remained unchanged. In contrast, NKG2D expression was substantially higher in controllers than in chronic patients (M=97.67, p<0.001). There were no significant differences in inhibitory receptors KIR3DL1 and KIR2DL1 expressions. In addition, plasma cytokine IFN-γ, TNF-α and IL-12showed higher levels in HIV controllers compared to chronic patients. Overall, our study revealed that, as compared to chronic patients, HIV controllers show an increased activating receptors expression and higher number ofCD56⁺/CD16^-NK cell subset, with increased expression levels of plasma cytokines, suggesting that higher immune activation in controllers may have a key role in killing and suppressing HIV.

Safety, Immune, and Antiviral Effects of Pegylated Interferon Alpha 2b Administration in Antiretroviral Therapy-Suppressed Individuals: Results of Pilot Clinical Trial

In the pilot NCT01935089 trial, we tested whether pegylated interferon alpha2b (Peg-IFN-α2b) with antiretroviral therapy (ART) was safe and could impact HIV and immune measures in blood and in gut-associated lymphoid tissue (GALT). Twenty HIV-1⁺ ART-suppressed individuals received 1 μg/kg/week Peg-IFN-α2b with ART for 20 weeks, with intermediate 4-week analytical ART interruption (ATI). Safety, immune activation, HIV viral load and integrated HIV DNA in blood, and HIV RNA and DNA in gut biopsies were measured. A total of 7/20 participants experienced grade 3-4 adverse events, while 17/20 participants completed the study. Of the 17 participants who completed the study, 8 remained suppressed during ATI, while all 17 were suppressed at end of treatment (EoT). As expected, treatment increased activation of T and natural killer (NK) cells and IFN-stimulated molecule expression on monocytes in periphery. While circulating CD4⁺ T cells showed a trend for a decrease in integrated HIV DNA, GALT showed a significant decrease in HIV-1 RNA⁺ cells as measured by in situ hybridization along with a reduction in total HIV DNA and cell-associated RNA by EoT. The observed decrease in HIV-1 RNA⁺ cells in GALT was positively associated with the decrease in activated NK cells and macrophages. This study documents for the first time that 20 weeks of immunotherapy with Peg-IFN-α2b+ART (inclusive of a 4-week ATI) is safe and results in an increase in blood and GALT immune activation and in a significant decrease in HIV-1 RNA⁺ cells in GALT in association with changes in innate cell activation.

Investigational drugs with dual activity against HBV and HIV (Review)

Chronic hepatitis B (CHB) and acquired immunodeficiency syndrome (AIDS) are global public health problems that pose a significant health burden. Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) coinfection is common, as these viruses have similar transmission routes, such as blood transmission, sexual transmission and mother-to-child transmission. Coinfection frequently leads to accelerated disease progression. For individuals coinfected with HIV/HBV, combination antiretroviral therapy containing dual anti-HBV drugs is recommended. Certain studies have also indicated the benefits of antiretroviral drugs with anti-HBV activity in patients with coinfection. A total of four Food and Drug Administration-approved HIV drugs also have anti-HBV activity; namely, emtricitabine, lamivudine, tenofovir disoproxil fumarate and tenofovir alafenamide, which are all nucleoside reverse transcriptase inhibitors. However, various issues, including drug resistance and side effects, limit their application. Therefore, it is necessary to develop more drugs with dual activity against HBV and HIV. The present review outlines the mechanisms, safety and efficacy of certain drugs that have been investigated for this purpose.

Contribution of NK cells to HBsAg seroconversion in inactive HBsAg carriers following pegylated IFN therapy

Our recent study showed a high rate of HBsAg seroconversion in inactive HBsAg carriers (IHCs) treated with pegylated IFN (PEG-IFN). To understand the immune-mediated component of the HBsAg seroconversion better, this study investigated the role of NK cells. A total of 44 IHCs were given 48 wk of PEG-IFN. Fifteen cases achieved HBsAg seroconversion (R group), whereas 29 failed (NR group). The proportion and activity (CD107α and IFN-γ production) of NK cells were measured before and during treatment. We found that the proportion of NK cells in the R group was higher than in the NR group at baseline and during PEG-IFN treatment, even when patients were matched for age, sex and treatment period. IFN- γ secretion and CD107α expression from NK cells in cases who achieved HBsAg seroconversion were significantly higher than patients matched for age, sex, HBsAg and treatment period in the NR group at baseline and during PEG-IFN treatment. We also found that in HBsAg seroconversion cases, NK cells activity increased after PEG-IFN treatment, especially before HBsAg seroconversion. These effects were not found in non-responders. In conclusion, we demonstrated that the increase of NK cells accompanied by enhanced activity during PEG-IFN treatment favoured HBsAg seroconversion for IHC, and that NK cells may play a role in HBV seroconversion.

Potential of the NKG2D/NKG2DL Axis in NK Cell-Mediated Clearance of the HIV-1 Reservoir

Viral persistency in latently infected CD4⁺ T cells despite antiretroviral therapy (ART) represents a major drawback in the fight against HIV-1. Efforts to purge latent HIV-1 have been attempted using latency reversing agents (LRAs) that activate expression of the quiescent virus. However, initial trials have shown that immune responses of ART-treated patients are ineffective at clearing LRA-reactivated HIV-1 reservoirs, suggesting that an adjuvant immunotherapy is needed. Here we overview multiple lines of evidence indicating that natural killer (NK) cells have the potential to induce anti-HIV-1 responses relevant for virus eradication. In particular, we focus on the role of the NKG2D activating receptor that crucially enables NK cell-mediated killing of HIV-1-infected cells. We describe recent data indicating that LRAs can synergize with HIV-1 at upregulating ligands for NKG2D (NKG2DLs), hence sensitizing T cells that exit from viral latency for recognition and lysis by NK cells; in addition, we report in vivo and ex vivo data showing the potential benefits and drawbacks that LRAs may have on NKG2D expression and, more in general, on the cytotoxicity of NK cells. Finally, we discuss how the NKG2D/NKG2DLs axis can be exploited for the development of effective HIV-1 eradication strategies combining LRA-induced virus reactivation with recently optimized NK cell-based immunotherapies.

Deficient IL-2 Produced by Activated CD56+ T Cells Contributes to Impaired NK Cell-Mediated ADCC Function in Chronic HIV-1 Infection

Background: Antibody-dependent cellular cytotoxicity (ADCC), which mainly mediated by natural killer (NK) cells, may play a critical role in human immunodeficiency virus type-1 (HIV-1) disease progression. However, the potential mechanisms that affecting NK-mediated ADCC response are still not well-elucidated. Methods: Antigen-antibody complex model of Ab-opsonized P815 cells was adopted to induce a typical non-specific ADCC response. The capacities of HIV-1 specific NK-ADCC were measured by using the combination model of gp120 protein and plasma of HIV-1 elite controllers. The levels of plasma cytokine were measured by ELISA. Anti-IL-2 blocking antibody was used to analyze the impact of activated CD56⁺ T cells on NK-ADCC response. Results: IL-2, IL-15, IFN-α, and IFN-β could effectively enhance the non-specific and HIV-1-specific NK-ADCC responses. Compared with healthy controls, HIV-1-infected patients showed decreased plasma IL-2 levels, while no differences of plasma IFN-α, IL-15, and IFN-β were presented. IL-2 production was detected from CD56⁺ T cells activated through antibody-dependent manner. The capability of NK-ADCC could be weakened by blocking IL-2 secretion from activated CD56⁺ T cells. Although no difference of frequencies of CD56⁺ T cells was found between HIV-1-infected patients and healthy controls, deficient IL-2 secretion from activated CD56⁺ T were found in chronic HIV-1 infection. Conclusions: The impaired ability of activated CD56⁺ T cells to secreting IL-2 might contribute to the attenuated NK cell-mediated ADCC function in HIV-1 infection.

NK Response Correlates with HIV Decrease in Pegylated IFN-α2a-Treated Antiretroviral Therapy-Suppressed Subjects

We previously reported that pegylated IFN-α2a (Peg-IFN-α2a) added to antiretroviral therapy (ART)-suppressed, HIV-infected subjects resulted in plasma HIV control and integrated HIV DNA decrease. We now evaluated whether innate NK cell activity or PBMC transcriptional profiles were associated with decreases in HIV measures. Human peripheral blood was analyzed prior to Peg-IFN-α2a administration (ART, baseline), after 5 wk of ART+Peg-IFN-α2a, and after 12 wk of Peg-IFN-α2a monotherapy (primary endpoint). After 5 wk of ART+Peg-IFN-α2a, immune subset frequencies were preserved, and induction of IFN-stimulated genes was noted in all subjects except for a subset in which the lack of IFN-stimulated gene induction was associated with increased expression of microRNAs. Viral control during Peg-IFN-α2a monotherapy was associated with 1) higher levels of NK cell activity and IFN-γ-induced protein 10 (IP-10) on ART (preimmunotherapy) and 2) downmodulation of NK cell KIR2DL1 and KIR2DL2/DL3 expression, transcriptional enrichment of expression of genes associated with NK cells in HIV controller subjects, and higher ex vivo IFN-α-induced NK cytotoxicity after 5 wk of ART+Peg-IFN-α2a. Integrated HIV DNA decline after immunotherapy was also associated with gene expression patterns indicative of cell-mediated activation and NK cytotoxicity. Overall, an increase in innate activity and NK cell cytotoxicity were identified as correlates of Peg-IFN-α2a-mediated HIV control.

HCV-coinfection is related to an increased HIV-1 reservoir size in cART-treated HIV patients: a cross-sectional study

In HIV-1/HCV-coinfected patients, chronic HCV infection leads to an increased T-lymphocyte immune activation compared to HIV-monoinfected patients, thereby likely contributing to increase HIV-1 reservoir that is the major barrier for its eradication. Our objective was to evaluate the influence of HCV coinfection in HIV-1 viral reservoir size in resting (r) CD4+ T-cells (CD25-CD69-HLADR-). Multicenter cross-sectional study of 97 cART-treated HIV-1 patients, including 36 patients with HIV and HCV-chronic co-infection without anti-HCV treatment, 32 HIV patients with HCV spontaneous clearance and 29 HIV-monoinfected patients. rCD4+ T-cells were isolated and total DNA was extracted. HIV viral reservoir was measured by Alu-LTR qPCR. Differences between groups were calculated with a generalized linear model. Overall, 63.9% were men, median age of 41 years and Caucasian. Median CD4+ and CD8+ T-lymphocytes were 725 and 858 cells/mm3, respectively. CD4+ T nadir cells was 305 cells/mm3. Proviral HIV-1 DNA size was significantly increased in chronic HIV/HCV-coinfected compared to HIV-monoinfected patients (206.21 ± 47.38 vs. 87.34 ± 22.46, respectively; P = 0.009), as well as in spontaneously clarified HCV co-infected patients when compared to HIV-monoinfected individuals (136.20 ± 33.20; P = 0.009). HIV-1/HCV co-infected patients showed a larger HIV-1 reservoir size in comparison to HIV-monoinfected individuals. This increase could lead to a greater complexity in the elimination of HIV-1 reservoir in HIV-1/HCV-coinfected individuals, which should be considered in the current strategies for the elimination of HIV-1 reservoir.

Interferon Alpha Enhances NK Cell Function and the Suppressive Capacity of HIV-Specific CD8+ T Cells

Current shock-and-kill strategies for the eradication of the HIV-1 reservoir have resulted in blips of viremia but not in a decrease in the size of the latent reservoir in patients on suppressive antiretroviral therapy (ART). This discrepancy could potentially be explained by an inability of the immune system to kill HIV-1-infected cells following the reversal of latency. Furthermore, some studies have suggested that certain latency-reversing agents (LRAs) may inhibit CD8⁺ T cell and natural killer (NK) cell responses. In this study, we tested the hypothesis that alpha interferon (IFN-α) could improve the function of NK cells from chronic progressors (CP) on ART. We show here that IFN-α treatment enhanced cytokine secretion, polyfunctionality, degranulation, and the cytotoxic potential of NK cells from healthy donors (HD) and CP. We also show that this cytokine enhanced the viral suppressive capacity of NK cells from HD and elite controllers or suppressors. Furthermore, IFN-α enhanced global CP CD8⁺ T cell cytokine responses and the suppressive capacity of ES CD8⁺ T cells. Our data suggest that IFN-α treatment may potentially be used as an immunomodulatory agent in HIV-1 cure strategies.IMPORTANCE Data suggest that HIV⁺ individuals unable to control infection fail to do so due to impaired cytokine production and/cytotoxic effector cell function. Consequently, the success of cure agendas such as the shock-and-kill strategy will probably depend on enhancing patient effector cell function. In this regard, NK cells are of particular interest since they complement the function of CD8⁺ T cells. Here, we demonstrate the ability of short-course alpha interferon (IFN-α) treatments to effectively enhance such effector functions in chronic progressor NK cells without inhibiting their general CD8⁺ T cell function. These results point to the possibility of exploring such short-course IFN-α treatments for the enhancement of effector cell function in HIV⁺ patients in future cure strategies.

HIV-1 Infection and Type 1 Interferon: Navigating Through Uncertain Waters

HIV-1 remains a chronic viral infection of global health importance. Although HIV-1 replication can be controlled by antiretroviral therapy (ART), there is no cure due to persistence of a long-lived latent reservoir. In addition, people living with HIV-1 who are taking ART still bear signatures of persistent immune activation that include continued type 1 interferon (IFN) signaling. Paradoxically, type 1 IFN exerts a limited role on the control of chronic HIV-1. Indeed, recent reports from humanized mice suggest that type 1 IFN may partly maintain the latent reservoir. In this review, we discuss the molecular interactions between HIV-1 and the type 1 IFN signaling pathway, and examine the efficacy of type 1 IFNs in vivo. We also explore whether limited type 1 IFN manipulation may have a therapeutic role.

Type I Interferons in NeuroHIV

Infection with Human Immunodeficiency Virus (HIV)-1 continues to cause HIV-associated neurocognitive disorders despite combined antiretroviral therapy. Interferons (IFNs) are important for any antiviral immune response, but the lasting production of IFNα causes exhaustive activation leading eventually to progression to AIDS. Expression of IFNα in the HIV-exposed central nervous system has been linked to cognitive impairment and inflammatory neuropathology. In contrast, IFNβ exerts anti-inflammatory effects, appears to control, at least temporarily, lentiviral infection in the brain and provides neuroprotection. The dichotomy of type I IFN effects on HIV-1 infection and the associated brain injury will be discussed in this review, because the underlying mechanisms require further investigation to allow harnessing these innate immune factors for therapeutic purposes.

Propofol Promotes Activity and Tumor-Killing Ability of Natural Killer Cells in Peripheral Blood of Patients with Colon Cancer

Background

We investigated the effect of propofol on activities and tumor-killing ability of natural killer (NK) cells in patients with colon cancer.

Material/Methods

Twenty colon cancer patients and 20 healthy subjects were included. Peripheral blood (5 ml) was collected from all patients and healthy subjects. NK cells in peripheral blood were separated by negative screening using immunomagnetic beads. Flow cytometry was used to determine expression of activated receptors, inhibitory receptors, killing effector molecules, and proliferation-associated markers on NK cell surfaces. After in vitro treatment with propofol for 24 h, expression of activated receptors, inhibitory receptors, killing effector molecules, and proliferation-associated markers on NK cell surfaces was examined again. In addition, the tumor-killing effect of NK cells was studied by co-culture with K562 cells or colon cancer SW620 cells at a ratio of 1: 1.

Results

The number of NK cells in peripheral blood from colon cancer patients was increased compared with healthy subjects, but activities and proliferation ability of the NK cells were decreased. The tumor-killing effect of NK cells isolated from colon cancer patients was decreased. Of note, propofol promoted activation of NK cells from colon cancer patients. In addition, propofol increased expression of tumor-killing effector molecules by NK cells and the proliferation ability of NK cells. Propofol also enhanced the killing effect of NK cells on colon cancer cells.

Conclusions

The present study demonstrates that propofol promotes the activity and tumor-killing ability of NK cells in peripheral blood of patients with colon cancer.

Targeting the Latent Reservoir for HIV-1

Antiretroviral therapy can effectively block HIV-1 replication and prevent or reverse immunodeficiency in HIV-1-infected individuals. However, viral replication resumes within weeks of treatment interruption. The major barrier to a cure is a small pool of resting memory CD4+ T cells that harbor latent HIV-1 proviruses. This latent reservoir is now the focus of an intense international research effort. We describe how the reservoir is established, challenges involved in eliminating it, and pharmacologic and immunologic strategies for targeting this reservoir. The development of a successful cure strategy will most likely require understanding the mechanisms that maintain HIV-1 proviruses in a latent state and pathways that drive the proliferation of infected cells, which slows reservoir decay. In addition, a cure will require the development of effective immunologic approaches to eliminating infected cells. There is renewed optimism about the prospect of a cure, and the interventions discussed here could pave the way.

Lymph Node Cellular and Viral Dynamics in Natural Hosts and Impact for HIV Cure Strategies

Combined antiretroviral therapies (cARTs) efficiently control HIV replication leading to undetectable viremia and drastic increases in lifespan of people living with HIV. However, cART does not cure HIV infection as virus persists in cellular and anatomical reservoirs, from which the virus generally rebounds soon after cART cessation. One major anatomical reservoir are lymph node (LN) follicles, where HIV persists through replication in follicular helper T cells and is also trapped by follicular dendritic cells. Natural hosts of SIV, such as African green monkeys and sooty mangabeys, generally do not progress to disease although displaying persistently high viremia. Strikingly, these hosts mount a strong control of viral replication in LN follicles shortly after peak viremia that lasts throughout infection. Herein, we discuss the potential interplay between viral control in LNs and the resolution of inflammation, which is characteristic for natural hosts. We furthermore detail the differences that exist between non-pathogenic SIV infection in natural hosts and pathogenic HIV/SIV infection in humans and macaques regarding virus target cells and replication dynamics in LNs. Several mechanisms have been proposed to be implicated in the strong control of viral replication in natural host's LNs, such as NK cell-mediated control, that will be reviewed here, together with lessons and limitations of in vivo cell depletion studies that have been performed in natural hosts. Finally, we discuss the impact that these insights on viral dynamics and host responses in LNs of natural hosts have for the development of strategies toward HIV cure.

Interferon-α Subtypes As an Adjunct Therapeutic Approach for Human Immunodeficiency Virus Functional Cure

Human immunodeficiency virus (HIV) establishes life-long latency in infected individuals. Although highly active antiretroviral therapy (HAART) has had a significant impact on the course of HIV infection leading to a better long-term outcome, the pool of latent reservoir remains substantial even under HAART. Numerous approaches have been under development with the goal of eradicating the latent HIV reservoir though with limited success. Approaches that combine immune-mediated control of HIV to activate both the innate and the adaptive immune system under suppressive therapy along with "shock and kill" drugs may lead to a better control of the reactivated virus. Interferon-α (IFN-α) is an innate cytokine that has been shown to activate intracellular defenses capable of restricting and controlling HIV. IFN-α, however, harbors numerous functional subtypes that have been reported to display different binding affinities and potency. Recent studies have suggested that certain subtypes such as IFN-α8 and IFN-α14 have potent anti-HIV activity with little or no immune activation, whereas other subtypes such as IFN-α4, IFN-α5, and IFN-α14 activate NK cells. Could these subtypes be used in combination with other strategies to reduce the latent viral reservoir? Here, we review the role of IFN-α subtypes in HIV infection and discuss the possibility that certain subtypes could be potential adjuncts to a "shock and kill" or therapeutic vaccination strategy leading to better control of the latent reservoir and subsequent functional cure.