Using safe, affordable and accessible non-steroidal anti-inflammatory drugs to reduce the number of HIV target cells in the blood and at the female genital tract

Comparison between a deep-learning and a pixel-based approach for the automated quantification of HIV target cells in foreskin tissue

The availability of target cells expressing the HIV receptors CD4 and CCR5 in genital tissue is a critical determinant of HIV susceptibility during sexual transmission. Quantification of immune cells in genital tissue is therefore an important outcome for studies on HIV susceptibility and prevention. Immunofluorescence microscopy allows for precise visualization of immune cells in mucosal tissues; however, this technique is limited in clinical studies by the lack of an accurate, unbiased, high-throughput image analysis method. Current pixel-based thresholding methods for cell counting struggle in tissue regions with high cell density and autofluorescence, both of which are common features in genital tissue. We describe a deep-learning approach using the publicly available StarDist method to count cells in immunofluorescence microscopy images of foreskin stained for nuclei, CD3, CD4, and CCR5. The accuracy of the model was comparable to manual counting (gold standard) and surpassed the capability of a previously described pixel-based cell counting method. We show that the performance of our deep-learning model is robust in tissue regions with high cell density and high autofluorescence. Moreover, we show that this deep-learning analysis method is both easy to implement and to adapt for the identification of other cell types in genital mucosal tissue.

Hydroxychloroquine reduces T cells activation recall antigen responses

BACKGROUND

In the context of the current COVID-19 pandemic, there is still limited information about how people suffering from autoimmune diseases respond to the different COVID vaccines. The fact that they are taking an immunosuppressant or other drugs that aim to decrease the immune system activities, such as hydroxychloroquine (HCQ), could also impact their ability to respond to a COVID vaccine and vaccines in general.

METHODS

Heathy donors were given 200mg of HCQ daily for 6-weeks to assess HCQs impact on the systemic T cells and humoral immune response. Peripheral blood mononuclear cells (PBMC) and plasma were obtained at baseline and 6-weeks after starting daily HCQ. Flow cytometry assays were designed to determine changes in T cell activation and T cell responses. Bead array multiplex were used to analyse antibodies and cytokine levels before and after HCQ intake.

RESULTS

As anticipated, HCQ treatment decreased ex vivo T cell activation. We observed a decrease in CD4+CD161- expressing CCR5 (p = 0.015) and CD69 (p = 0.004) as well as in CD8+CCR5+ (p = 0.003), CD8+CD161+CCR5+ (p = 0.002) and CD8+CD161+CD95+ (p = 0.004). Additionally, HCQ decreased the proportion of Th17 expressing CD29 (p = 0.019), a subset associated with persistent inflammation. The proportion of T regulatory cells expressing the inhibitory molecule TIGIT was also reduced by HCQ (p = 0.003). As well, T cells from people on HCQ were less responsive to activation and cytokine production following stimulation with recall antigens and memory T cells were less likely to produce both IFNγ and TNFα following stimulation.

CONCLUSION

This study shows HCQ is associated with lower T cell activation and decreased T cell cytokine production. While this study was not performed with the intent of looking at COVID vaccine response, it does provide important information about the changes in immune response that may occur in patient taking HCQ as a treatment for their autoimmune disease.

Low-Dose Acetylsalicylic Acid Reduces T Cell Immune Activation: Potential Implications for HIV Prevention

Introduction

Acetylsalicylic acid (ASA) is a well-known and safe anti-inflammatory. At low-dose, it is prescribed to prevent secondary cardiovascular events in those with pre-existing conditions and to prevent preeclampsia. Little is known about how low-dose ASA affects the immune response. In this study, we followed women to assess how ASA use modifies T cells immune phenotypes in the blood and at the genital tract.

Methods

HIV uninfected women from Kenya were enrolled in this study and followed for one month to assess baseline responses including systemic/mucosal baseline immune activation. Participants then received 81mg of ASA daily for 6 weeks to assess changes to T cell immune activation (systemic and mucosal) relative to baseline levels.

Results

The concentration of ASA measured in the blood was 58% higher than the level measured at the female genital tract. In the blood, the level of ASA was inversely correlated with the following: the proportion of Th17 expressing HLA-DR (p=0.04), the proportion of effector CD4⁺ T cells expressing CCR5 (p=0.03) and the proportion of CD8⁺Tc17 expressing CCR5 (p=0.04). At the genital tract, ASA use correlated with a decreased of activated CD4⁺T cells [CD4⁺CCR5⁺CD161⁺ (p=0.02) and CD4⁺CCR5⁺CD95⁺ (p=0.001)].

Conclusion

This study shows that ASA use impacts the immune response in both the systemic and genital tract compartments. This could have major implications for the prevention of infectious diseases such as HIV, in which the virus targets activated T cells to establish an infection. This could inform guidelines on ASA use in women.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT02079077.

Machine Learning-Based HIV Risk Estimation Using Incidence Rate Ratios

HIV/AIDS is an ongoing global pandemic, with an estimated 39 million infected worldwide. Early detection is anticipated to help improve outcomes and prevent further infections. Point-of-care diagnostics make HIV/AIDS diagnoses available both earlier and to a broader population. Wide-spread and automated HIV risk estimation can offer objective guidance. This supports providers in making an informed decision when considering patients with high HIV risk for HIV testing or pre-exposure prophylaxis (PrEP). We propose a novel machine learning method that allows providers to use the data from a patient's previous stays at the clinic to estimate their HIV risk. All features available in the clinical data are considered, making the set of features objective and independent of expert opinions. The proposed method builds on association rules that are derived from the data. The incidence rate ratio (IRR) is determined for each rule. Given a new patient, the mean IRR of all applicable rules is used to estimate their HIV risk. The method was tested and validated on the publicly available clinical database MIMIC-IV, which consists of around 525,000 hospital stays that included a stay at the intensive care unit or emergency department. We evaluated the method using the area under the receiver operating characteristic curve (AUC). The best performance with an AUC of 0.88 was achieved with a model consisting of 53 rules. A threshold value of 0.66 leads to a sensitivity of 98% and a specificity of 53%. The rules were grouped into drug abuse, psychological illnesses (e.g., PTSD), previously known associations (e.g., pulmonary diseases), and new associations (e.g., certain diagnostic procedures). In conclusion, we propose a novel HIV risk estimation method that builds on existing clinical data. It incorporates a wide range of features, leading to a model that is independent of expert opinions. It supports providers in making informed decisions in the point-of-care diagnostics process by estimating a patient's HIV risk.

Nonsteroidal anti-inflammatory drugs restore immune function to respiratory syncytial virus in geriatric cotton rats (Sigmodon hispidus)

Respiratory syncytial virus (RSV) infection is not only a childhood disease, but also a serious health risk for the elderly. We investigated in cotton rats how age affected viral clearance, immune responses, and whether pharmacological intervention was beneficial. Our results demonstrated that in geriatric animals, virus grew to similar titers, but with delayed clearance, compared to adult animals. After primary infection with RSV, geriatric animals were susceptible to secondary infection and results indicated a defective humoral immune response. Depletion of cytotoxic T lymphocytes (CTL) during primary infection delayed clearance, indicating the necessary role of CTL. Pharmacological intervention through nonsteroidal anti-inflammatory ibuprofen resulted in faster viral clearance and complete protection after immunization. In addition, the CTL response in the presence of ibuprofen seemed to be restored. It appears that in geriatric animals, immune functions are not as effective as in adult animals and that anti-inflammatory therapy may restore effective immune function.

Proinflammatory oscillations over the menstrual cycle drives bystander CD4 T cell recruitment and SHIV susceptibility from vaginal challenge

BACKGROUND

The menstrual cycle influences HIV infection-risk in women, although the timing and underlying mechanism are unclear. Here we investigated the contribution of the menstrual cycle to HIV susceptibility through evaluating immune behavior with infection-risk over time.

METHODS

Blood and vaginal lavage samples were collected from 18 pig-tailed macaques to evaluate immune changes over reproductive cycles, and from 5 additional animals undergoing repeated vaginal exposures to simian HIV (SHIV). Peripheral blood mononuclear cell (PBMC) samples from healthy women (n = 10) were prospectively collected over the course of a menstrual cycle to profile T cell populations. Immune properties from PBMC and vaginal lavage samples were measured by flow cytometry. Plasma progesterone was measured by enzyme immunoassay. The oscillation frequency of progesterone concentration and CCR5 expression on CD4 T cells was calculated using the Lomb-Scargle periodogram. SHIV infection was monitored in plasma by RT-PCR. Immune measures were compared using generalized estimating equations (GEE).

FINDINGS

Macaques cycle-phases were associated with fluctuations in systemic immune properties and a type-1 inflammatory T cell response with corresponding CCR5+ memory CD4 T cell (HIV target cell) infiltration into the vaginal lumen at the late luteal phase. Power spectral analysis identified CCR5 oscillation frequencies synchronized with reproductive cycles. In a repetitive low-dose vaginal challenge model, productive SHIV_163P3 infection only occurred during intervals of mounting type-1 T cell responses (n = 5/5). Finally, we identify similar type-1 inflammatory T cell responses over the menstrual cycle are occurring in healthy women.

INTERPRETATION

These data demonstrate that periodic shifts in the immune landscape under menstrual cycle regulation drives bystander CCR5+ CD4 T cell recruitment and HIV susceptibility in the female reproductive tract.

FUNDING

This study was supported by the U.S. Centers for Disease Control and Prevention, Atlanta, GA 30329 and NIH grants to Emory University (K23AI114407 to A.N.S., the Emory University Center for AIDS research [P30AI050409], and Atlanta Clinical and Translational Sciences Institute [KLR2TR000455, UL1TR000454]).

DISCLAIMER

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the U.S. Centers for Disease Control and Prevention or the Department of Health and Human Services.

Microbial mismanagement: how inadequate treatments for vaginal dysbiosis drive the HIV epidemic in women

Women and girls represent a key population driving new HIV infections and persistence of the HIV pandemic. A key determinant of HIV susceptibility is the composition of the vaginal microbiome, which can influence the local immune cell population, inflammation status, and HIV prevention drug levels. While a low-diversity composition dominated by Lactobacillus crispatus is associated with a decreased risk of HIV acquisition, high diversity environments associated with bacterial vaginosis increase risk of HIV. Given the important role of the vaginal microbiome in determining HIV susceptibility, altering the microbiome towards a Lactobacillus-dominated state is an attractive complementary strategy to reduce HIV incidence rates. Here, we provide an overview of the mechanisms by which the vaginal microbiome may contribute to HIV acquisition risk. Furthermore, we address the advantages and limitations of historical treatments and emerging technologies under investigation to modify the vaginal microbiome, including: antibiotics, bacteriophages, probiotics, topicals, and engineered bacteria. By addressing the current state of vaginal microbiome knowledge and strategies for manipulation, we hope to amplify the growing calls for increased resources and research into vaginal microbial health, which will be essential to accelerating preventative efforts amongst the world's most vulnerable populations.

Segmented intravaginal ring for the combination delivery of hydroxychloroquine and anti-CCR5 siRNA nanoparticles as a potential strategy for preventing HIV infection

Abstract 

Vaginal drug delivery has been shown to be a promising strategy for the prevention of sexually transmitted infections. Therapy delivered at the site of infection has many advantages including improved therapeutic efficacy, reduction in systemic toxicity, and reduced potential for development of drug resistance. We developed a “smart” combination intravaginal ring (IVR) that will (1) provide continuous release of hydroxychloroquine (HCQ) to induce T cell immune quiescence as the first-line of defense and (2) release nanoparticles containing anti-CCR5 siRNA only during sexual intercourse when triggered by the presence of seminal fluid as the second-line of defense. The IVR was capable of releasing HCQ over 25 days with a mean daily release of 31.17 ± 3.06 µg/mL. In the presence of vaginal fluid simulant plus seminal fluid simulant, over 12 × more nanoparticles (5.12 ± 0.9 mg) were released over a 4-h period in comparison to IVR segments that were incubated in the presence of vaginal fluid simulant alone (0.42 ± 0.19 mg). Anti-CCR5 siRNA nanoparticles were able to knockdown 83 ± 5.1% of CCR5 gene expression in vitro in the CD4⁺ T cell line Sup-T1. The IVR system also demonstrated to be non-cytotoxic to VK2/E6E7 vaginal epithelial cells.

Graphical abstract

Differential Elevation of Inflammation and CD4+ T Cell Activation in Kenyan Female Sex Workers and Non-Sex Workers Using Depot-Medroxyprogesterone Acetate

Background

Depot Medroxyprogesterone (DMPA) is one of the most widely used contraceptives in Sub-Saharan Africa where HIV incidence is high. We explored the effect of DMPA on the activation of HIV cellular targets and inflammation as a possible mechanism of increased HIV risk with DMPA use. Since sex work is known to affect the immune system, this study aimed to understand the effect of DMPA on the immune system among sex workers and non-sex worker women.

Methods

Twenty-seven DMPA-using HIV seronegative female sex workers (FSW) and 30 DMPA-using HIV seronegative non-sex worker (SW) women were enrolled in the study. Twenty-four FSWs and 30 non-sex workers who were not using any hormonal contraception (no HC) were recruited as controls. Blood and cervico-vaginal samples were collected from all participants and assayed for T cell activation and proinflammatory cytokines.

Results

Among no HC users, sex workers had lower expression of CD38 and CD69 on blood-derived CD4⁺ T cells along with lower CD4⁺CCR5⁺ cells frequency in the endocervix. Plasma MCP-1, TNFα and IL-17 also had reduced expression in FSW not using HC. Non-sex workers using DMPA had elevated proportions of blood-derived CD4⁺CD38⁺, CD4⁺CD69⁺ and CD4⁺HLA-DR⁺ T cells relative to non-sex workers who were not taking any HC. DMPA-using non-sex workers also had an increased level of plasma interferon gamma (IFN-γ), monokine induced by interferon-γ (MIG) and sCD40L, alongside higher proportion of CD4⁺CD38⁺ and CD4⁺CD69⁺ T cells at the cervix compared to non-sex workers no-HC controls., Finally, non-sex workers and FSWs using DMPA had similar levels of genital and peripheral CD4⁺ T cell activation and inflammation.

Conclusion

DMPA increased inflammation and expression of activation markers on potential HIV target cells in non-sex workers. These data show that DMPA is a strong immune modulator and its use counteracts the decreased immune activation associated with sex work. These findings suggest that inflammation and increased HIV target cells in blood and at the genital tract may be mechanisms by which DMPA increases susceptibility to HIV.

HIV susceptibility in women: The roles of genital inflammation, sexually transmitted infections and the genital microbiome

Given that heterosexual transmission of HIV across the genital mucosa is the most common route of infection in women, an in-depth understanding of the biological mechanisms associated with HIV risk in the female genital tract (FGT) is essential for effective control of the epidemic. Genital pro-inflammatory cytokines are well-described biological co-factors to HIV risk. Increased levels of pro-inflammatory cytokines in the FGT have been associated with a 3-fold higher-risk of acquiring HIV, presumably through involvement in barrier compromise and the recruitment of highly activated HIV target cells to the site of initial viral infection and replication. Sexually transmitted infections (STIs) and bacterial vaginosis (BV) are suggested possible contributors to genital inflammation in the FGT, and this, coupled with the relationship between genital inflammation and HIV risk, underscores the importance of effective treatment of STI and BV in the promotion of women's health. In most low- and middle-income countries, STIs are treated syndromically, a practice providing rapid treatment without identifying the infection source. However, this approach has been associated with over-diagnosis and the overuse of drugs. Further, because many women with STIs are asymptomatic, syndromic management also fails to treat a vast proportion of infected women. Although several studies have explored the role of STIs and the vaginal microbiome on genital inflammation and HIV risk, the impact of STI and BV management on genital inflammation remains poorly understood. This review aimed to collate the evidence on how BV and STI management efforts affect genital inflammation and the genital microbiome in women.

Inflammation, HIV, and Immune Quiescence: Leveraging on Immunomodulatory Products to Reduce HIV Susceptibility

The relationship between inflammation and HIV has been a focus of research over the last decade. In HIV-infected individuals, increased HIV-associated immune activation significantly correlated to disease progression. While genital inflammation (GI) has been shown to significantly increase the risk of HIV acquisition and transmission, immune correlates for reduced risk remain limited. In certain HIV-exposed seronegative individuals, an immune quiescent phenotype characterized reduced risk. Immune quiescence is defined by specific, targeted, highly regulated immune responses that hinder overt inflammation or immune activation. Targeted management of inflammation, therefore, is a plausible strategy to mitigate HIV risk and slow disease progression. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as hydroxychloroquine and aspirin have shown encouraging preliminary results in low-risk women by reducing systemic and genital immune activation. A topical NSAID, containing ibuprofen, is effective in treating vulvovaginal inflammation. Additionally, the glucocorticoids (GCs), prednisolone, and dexamethasone are used to treat HIV-associated immune activation. Collectively, these data inform on immune-modulating drugs to reduce HIV risk. However, the prolonged use of these pharmaceutical drugs is associated with adverse effects, both systemically and to a lesser extent topically. Natural products with their reduced side effects coupled with anti-inflammatory properties render them viable options. Lactic acid (LA) has immunomodulatory properties. LA regulates the genital microbiome by facilitating the growth of Lactobacillus species, while simultaneously limiting bacterial species that cause microbial dysbiosis and GI. Glycerol monolaurate, besides being anti-inflammatory, also inhibited SIV infections in rhesus macaques. The proposed pharmaceutical and natural products could be used in combination with either antiretrovirals for treatment or preexposure prophylaxis for HIV prevention. This review provides a summary on the associations between inflammation, HIV risk, and disease progression. Furthermore, we use the knowledge from immune quiescence to exploit the use of pharmaceutical and natural products as strategic interventions to manage inflammation, toward mitigating HIV infections.

Epigenetic regulation of ACE2, the receptor of the SARS-CoV-2 virus1

The angiotensin-converting enzyme 2 (ACE2) is the receptor for the three coronaviruses HCoV-NL63, SARS-CoV, and SARS-CoV-2. ACE2 is involved in the regulation of the renin-angiotensin system and blood pressure. ACE2 is also involved in the regulation of several signaling pathways, including integrin signaling. ACE2 expression is regulated transcriptionally and post-transcriptionally. The expression of the gene is regulated by two promoters, with usage varying among tissues. ACE2 expression is greatest in the small intestine, kidney, and heart and detectable in a variety of tissues and cell types. Herein we review the chemical and mechanical signal transduction pathways regulating the expression of the ACE2 gene and the epigenetic/chromatin features of the expressed gene.

Is Acetylsalicylic Acid a Safe and Potentially Useful Choice for Adult Patients with COVID-19 ?

Severe Acute Respiratory Syndrome-Coronavirus-2 is responsible for the current pandemic that has led to more than 10 million confirmed cases of Coronavirus Disease-19 (COVID-19) and over 500,000 deaths worldwide (4 July 2020). Virus-mediated injury to multiple organs, mainly the respiratory tract, activation of immune response with the release of pro-inflammatory cytokines, and overactivation of the coagulation cascade and platelet aggregation leading to micro- and macrovascular thrombosis are the main pathological features of COVID-19. Empirical multidrug therapeutic approaches to treat COVID-19 are currently used with extremely uncertain outcomes, and many others are being tested in clinical trials. Acetylsalicylic acid (ASA) has both anti-inflammatory and antithrombotic effects. In addition, a significant ASA-mediated antiviral activity against DNA and RNA viruses, including different human coronaviruses, has been documented. The use of ASA in patients with different types of infections has been associated with reduced thrombo-inflammation and lower rates of clinical complications and in-hospital mortality. However, safety issues related both to the risk of bleeding and to that of developing rare but serious liver and brain damage mostly among children (i.e., Reye's syndrome) should be considered. Hence, whether ASA might be a safe and reasonable therapeutic candidate to be tested in clinical trials involving adults with COVID-19 deserves further attention. In this review we provide a critical appraisal of current evidence on the anti-inflammatory, antithrombotic, and antiviral effects of ASA, from both a pre-clinical and a clinical perspective. In addition, the potential benefits and risks of use of ASA have been put in the context of the adult-restricted COVID-19 population.

Betamethasone induces potent immunosuppression and reduces HIV infection in a PBMC in vitro model

Genital inflammation is an established risk factor for increased HIV acquisition risk. Certain HIV-exposed seronegative populations, who are naturally resistant to HIV infection, have an immune quiescent phenotype defined by reduced immune activation and inflammatory cytokines at the genital tract. Therefore, the aim of this study was to create an immune quiescent environment using immunomodulatory drugs to mitigate HIV infection. Using an in vitro peripheral blood mononuclear cell (PBMC) model, we found that inflammation was induced using phytohemagglutinin and Toll-like receptor (TLR) agonists Pam3CSK4 (TLR1/2), lipopolysaccharide (LPS) (TLR4) and R848 (TLR7/8). After treatment with anti-inflammatory drugs, ibuprofen (IBF) and betamethasone (BMS), PBMCs were exposed to HIV NL4-3 AD8. Multiplexed ELISA was used to measure 28 cytokines to assess inflammation. Flow cytometry was used to measure immune activation (CD38, HLA-DR and CCR5) and HIV infection (p24 production) of CD4+ T cells. BMS potently suppressed inflammation (soluble cytokines, p<0.05) and immune activation (CD4+ T cells, p<0.05). BMS significantly reduced HIV infection of CD4+ T cells only in the LPS (0.98%) and unstimulated (1.7%) conditions (p<0.02). In contrast, IBF had minimal anti-inflammatory and immunosuppressive but no anti-HIV effects. BMS demonstrated potent anti-inflammatory effects, regardless of stimulation condition. Despite uniform immunosuppression, BMS differentially affected HIV infection according to the stimulation conditions, highlighting the complex nature of these interactions. Together, these data underscore the importance of interrogating inflammatory signaling pathways to identify novel drug targets to mitigate HIV infection.

Sterol metabolism modulates susceptibility to HIV-1 Infection

BACKGROUND

25-hydroxylase (CH25H) is an interferon-stimulated gene (ISG), which catalyzes the synthesis of 25-hydroxycholesterol (25HC). 25HC intervenes in metabolic and infectious processes and controls cholesterol homeostasis and influences viral entry into host cells. We verified whether natural resistance to HIV-1 infection in HIV-1-exposed seronegative (HESN) individuals is at least partially mediated by particularities in sterol biosynthesis.

METHODS

Peripheral blood mononuclear cells (PBMCs) and monocyte-derived macrophages (MDMs) isolated from 15 sexually exposed HESN and 15 healthy controls were in vitro HIV-1-infected and analyzed for: percentage of IFNα-producing plasmacytoid dendritic cells (pDCs); cholesterol signaling and inflammatory response RNA expression; resistance to HIV-1 infection. MDMs from five healthy controls were in vitro HIV-1-infected in the absence/presence of exogenously added 25HC.

RESULTS

IFNα-producing pDCs were augmented in HESN compared with healthy controls both in unstimulated and in in vitro HIV-1-infected PBMCs (P < 0.001). An increased expression of CH25H and of a number of genes involved in cholesterol metabolism (ABCA1, ABCG1, CYP7B1, LXRα, OSBP, PPARγ, SCARB1) was observed as well; this, was associated with a reduced susceptibility to in-vitro HIV-1-infection of PBMCs and MDMs (P < 0.01). Notably, addition of 25HC to MDMs resulted in increased cholesterol efflux and augmented resistance to in-vitro HIV-1-infection.

CONCLUSION

Results herein show that in HESN sterol metabolism might be particularly efficient. This could be related to the activation of the IFNα pathway and results into a reduced susceptibility to in-vitro HIV-1 infection. These results suggest a possible basis for therapeutic interventions to modulate HIV-1 infection.

Mucosal Immunity and HIV Acquisition in Women

Women acquire HIV through sexual transmission. Women worldwide represent half of the people living with HIV, but young women in endemic areas are disproportionally affected. Low transmission rates per sexual act in women suggest that local immune protective mechanisms in the genital tract have the potential to prevent infection. However, conditions that induce genital inflammation are known to increase the risk of HIV acquisition. The female genital tract (FGT) is divided into different anatomical compartments with distinct reproductive functions. The immune cells present in each of these compartments are specialized in balancing reproduction and protection against infections, and are the same cells that can encounter and respond to HIV. Understanding the physiological and pathological factors that influence mucosal immune cell presence, susceptibility to HIV-infection and anti-HIV immune responses in the FGT is necessary to develop preventive strategies. Here we review recent advances in our understanding of HIV infection in the human female genital tract, with an emphasis on the characterization of the mucosal cells susceptible to HIV-infection, innate immune responses and mucosal factors that increase genital inflammation and influence susceptibility to HIV acquisition in women.

New Th17-specific therapeutic strategies for HIV remission

PURPOSE OF REVIEW

This review highlights current knowledge on the dichotomous role played by T helper 17 cells (Th17)-polarized CD4 T cells in maintaining mucosal immunity homeostasis versus fueling HIV/simian immunodeficiency virus (SIV) replication/persistence during antiretroviral therapy (ART), with a focus on molecular mechanisms underlying these processes.

RECENT FINDING

Th17 cells bridge innate and adaptive immunity against pathogens at mucosal barrier surfaces. Th17 cells are located at portal sites of HIV/SIV entry, express a unique transcriptional/metabolic status compatible with viral replication, and represent the first targets of infection. The paucity of Th17 cells during HIV/SIV infection is caused by infection itself, but also by an altered Th17 differentiation, survival, and trafficking into mucosal sites. This causes major alterations of mucosal barrier integrity, microbial translocation, and disease progression. Unless initiated during the early acute infection phases, ART fails to restore the frequency/functionality of mucosal Th17 cells. A fraction of Th17 cells is long-lived and carry HIV reservoir during ART. Recent studies identified Th17-specific host factors controlling HIV transcription, a step untargeted by current ART.

SUMMARY

The identification of molecular mechanisms contributing to HIV replication/persistence in mucosal Th17 cells paves the way toward the design of new Th17-specific therapeutic strategies aimed at improving mucosal immunity in HIV-infected individuals.

Current State of Microbicide Development

Efforts in developing an effective vaccine for human immunodeficiency virus (HIV) has been challenging as HIV strains are highly variable and exhibit extraordinary mutability. Despite condom usage and pre-exposure prophylaxis as excellent prevention strategies, lack of accessibility in some developing countries and low adherence due to sociocultural factors continue to act as barriers in reducing the HIV epidemic. Microbicides are topical therapies developed to prevent HIV and other sexually transmitted infections during intercourse. Microbicides applied vaginally or rectally are intended to prevent HIV infection at the site of transmission by either inhibiting its entry into immune cells or prevent viral replication. This review will summarize some of the current state-of-the-art microbicide formulations that are in preclinical and clinical stages of development and discuss some of the challenges associated with microbicide development.