Bacterial Vaginosis Is Associated with Loss of Gamma Delta T Cells in the Female Reproductive Tract in Women in the Miami Women Interagency HIV Study (WIHS): A Cross Sectional Study

Gamma delta (γδ) T cells in the female reproductive tract: active participants or indifferent bystanders in reproductive success?

The female reproductive tract accommodates and balances the unique immunological challenges of protection from sexually transmitted pathogens and tolerance of the fetus and placenta in pregnancy. Leukocytes in the female reproductive tract actively engage in extensive maternal adaptations that are imperative for embryo implantation, placental development, and fetal growth support. γδ T cells are abundant at many mucosal sites in the body, where they provide protection against pathogens and cancer, and have roles in tissue renewal and homeostasis. In this review, we summarize studies in humans and rodents showing that γδ T cells are prevalent in the female reproductive tract and fluctuate in response to hormone changes across the reproductive cycle. Emerging evidence points to a link between changes in their abundance and molecular repertoire in the uterus and pregnancy disorders including recurrent miscarriage and preterm birth. However, defining the precise functional role of female reproductive tract γδ T cells and understanding their physiological significance in reproduction and pregnancy have remained elusive. Here, we critically analyze whether reproductive tract γδ T cells could be active participants in reproductive events-or whether their principal function is immune defense, in which case they may compromise pregnancy success unless adequately regulated.

Double-edged sword: γδ T cells in mucosal homeostasis and disease

The mucosa is a tissue that covers numerous body surfaces, including the respiratory tract, digestive tract, eye, and urogenital tract. Mucosa is in direct contact with pathogens, and γδ T cells perform various roles in the tissue. γδ T cells efficiently defend the mucosa from various pathogens, such as viruses, bacteria, and fungi. In addition, γδ T cells are necessary for the maintenance of homeostasis because they select specific organisms in the microbiota and perform immunoregulatory functions. Furthermore, γδ T cells directly facilitate pregnancy by producing growth factors. However, γδ T cells can also play detrimental roles in mucosal health by amplifying inflammation, thereby worsening allergic responses. Moreover, these cells can act as major players in autoimmune diseases. Despite their robust roles in the mucosa, the application of γδ T cells in clinical practice is lacking because of factors such as gaps between mice and human cells, insufficient knowledge of the target of γδ T cells, and the small population of γδ T cells. However, γδ T cells may be attractive targets for clinical use due to their effector functions and low risk of inducing graft-versus-host disease. Therefore, robust research on γδ T cells is required to understand the crucial features of these cells and apply these knowledges to clinical practices.

HIV-1-Host Interaction in Gut-Associated Lymphoid Tissue (GALT): Effects on Local Environment and Comorbidities

HIV-1 replication in the gastrointestinal (GI) tract causes severe CD4+ T-cell depletion and disruption of the protective epithelial barrier in the intestinal mucosa, causing microbial translocation, the main driver of inflammation and immune activation, even in people living with HIV (PLWH) taking antiretroviral drug therapy. The higher levels of HIV DNA in the gut compared to the blood highlight the importance of the gut as a viral reservoir. CD4+ T-cell subsets in the gut differ in phenotypic characteristics and differentiation status from the ones in other tissues or in peripheral blood, and little is still known about the mechanisms by which the persistence of HIV is maintained at this anatomical site. This review aims to describe the interaction with key subsets of CD4+ T cells in the intestinal mucosa targeted by HIV-1 and the role of gut microbiome and its metabolites in HIV-associated systemic inflammation and immune activation that are crucial in the pathogenesis of HIV infection and related comorbidities.

The Female Reproductive Tract Microbiota: Friends and Foe

We do not seem to be the only owner of our body; it houses a large population of microorganisms. Through countless years of coevolution, microbes and hosts have developed complex relationships. In the past few years, the impact of microbial communities on their host has received significant attention. Advanced molecular sequencing techniques have revealed a remarkable diversity of the organ-specific microbiota populations, including in the reproductive tract. Currently, the goal of researchers has shifted to generate and perceive the molecular data of those hidden travelers of our body and harness them for the betterment of human health. Recently, microbial communities of the lower and upper reproductive tract and their correlation with the implication in reproductive health and disease have been extensively studied. Many intrinsic and extrinsic factors influences the female reproductive tract microbiota (FRTM) that directly affects the reproductive health. It is now believed that FRTM dominated by Lactobacilli may play an essential role in obstetric health beyond the woman's intimate comfort and well-being. Women with altered microbiota may face numerous health-related issues. Altered microbiota can be manipulated and restored to their original shape to re-establish normal reproductive health. The aim of the present review is to summarize the FRTM functional aspects that influence reproductive health.

Gardnerella subgroup dominant microbiomes are associated with divergent cervicovaginal immune responses in a longitudinal cohort of Kenyan women

Most cervicovaginal microbiome-immunology studies to date have relied on 16S rDNA microbial profiling which does not resolve the molecular subgroups of Gardnerella, believed to be central to the pathogenesis of bacterial vaginosis (BV) and subsequent risk of HIV acquisition. Here we used the cpn60 universal target which in addition to other microbial taxa, resolves four Gardnerella subgroups, for cervicovaginal microbial profiling in a longitudinal cohort of Kenyan women to examine associations with cellular and soluble markers of inflammation and HIV susceptibility. Participants (N = 41) were sampled, contributing 362 samples for microbiome analysis. All non-Lactobacillus dominant microbial communities were associated with high pro-inflammatory cytokine levels. Divergent associations were observed among different Gardnerella subgroup dominated communities with respect to the chemokine IP-10. Specifically, Gardnerella subgroup A dominant and polymicrobial communities were associated with reduced concentrations of IP-10 in adjusted linear mixed models (p<0.0001), compared to microbial communities dominated by Lactobacillus (non-iners) species. However, these associations did not translate to significant differences in the proportion or absolute number of CCR5, HLA-DR and CD38 expressed on cervical CD4⁺ T- cells. These findings suggest that some associations between Gardnerella subgroup dominant microbiomes and mucosal immunity differ and are relevant for the study of BV-pathogenesis and understanding the mechanisms of BV-associated HIV risk.

Interactions between microbiota and cervical epithelial, immune, and mucus barrier

The female reproductive tract harbours hundreds of bacterial species and produces numerous metabolites. The uterine cervix is located between the upper and lower parts of the female genital tract. It allows sperm and birth passage and hinders the upward movement of microorganisms into a relatively sterile uterus. It is also the predicted site for sexually transmitted infection (STI), such as Chlamydia, human papilloma virus (HPV), and human immunodeficiency virus (HIV). The healthy cervicovaginal microbiota maintains cervical epithelial barrier integrity and modulates the mucosal immune system. Perturbations of the microbiota composition accompany changes in microbial metabolites that induce local inflammation, damage the cervical epithelial and immune barrier, and increase susceptibility to STI infection and relative disease progression. This review examined the intimate interactions between the cervicovaginal microbiota, relative metabolites, and the cervical epithelial-, immune-, and mucus barrier, and the potent effect of the host-microbiota interaction on specific STI infection. An improved understanding of cervicovaginal microbiota regulation on cervical microenvironment homeostasis might promote advances in diagnostic and therapeutic approaches for various STI diseases.

(Not) Home alone: Antigen presenting cell - T Cell communication in barrier tissues

Priming of T cells by antigen presenting cells (APCs) is essential for T cell fate decisions, enabling T cells to migrate to specific tissues to exert their effector functions. Previously, these interactions were mainly explored using blood-derived cells or animal models. With great advances in single cell RNA-sequencing techniques enabling analysis of tissue-derived cells, it has become clear that subsets of APCs are responsible for priming and modulating heterogeneous T cell effector responses in different tissues. This composition of APCs and T cells in tissues is essential for maintaining homeostasis and is known to be skewed in infection and inflammation, leading to pathological T cell responses. This review highlights the commonalities and differences of T cell priming and subsequent effector function in multiple barrier tissues such as the skin, intestine and female reproductive tract. Further, we provide an overview of how this process is altered during tissue-specific infections which are known to cause chronic inflammation and how this knowledge could be harnessed to modify T cell responses in barrier tissue.

A Syndemic Approach to Explore Factors Associated with Bacterial Vaginosis

Bacterial vaginosis (BV) is the most common genital infection in women and is associated with an increased risk of sexually transmitted infections and HIV. This study uses a syndemic approach to evaluate factors associated with BV. Non-pregnant, HIV-negative, sexually active, cis-gender women aged 18-45 years living in Miami, Florida were recruited from Nov.2018- Jun.2021. Participants completed a sociodemographic and behavioral questionnaire along with gynecological examinations. BV was diagnosed by Amsel criteria and confirmed by a Nugent score ≥ 4. A syndemic score was calculated as the sum of factors associated with BV. The association between syndemic score and BV was assessed using logistic regression. Of 166 women included, 60.2% had BV. Race, ethnicity, education, vaginal sex, recent cannabis use, and reasons for intravaginal practices were included in the syndemic score. Higher odds of BV were found in women with a score of ≥ 3 compared to women with a score of 0/1. A higher syndemic score was associated with increased odds of having BV. Multilevel interventions to decrease BV are needed to decrease women's risk of acquiring HIV.

Role of Vγ9vδ2 T lymphocytes in infectious diseases

The T cell receptor Vγ9Vδ2 T cells bridge innate and adaptive antimicrobial immunity in primates. These Vγ9Vδ2 T cells respond to phosphoantigens (pAgs) present in microbial or eukaryotic cells in a butyrophilin 3A1 (BTN3) and butyrophilin 2A1 (BTN2A1) dependent manner. In humans, the rapid expansion of circulating Vγ9Vδ2 T lymphocytes during several infections as well as their localization at the site of active disease demonstrates their important role in the immune response to infection. However, Vγ9Vδ2 T cell deficiencies have been observed in some infectious diseases such as active tuberculosis and chronic viral infections. In this review, we are providing an overview of the mechanisms of Vγ9Vδ2 T cell-mediated antimicrobial immunity. These cells kill infected cells mainly by releasing lytic mediators and pro-inflammatory cytokines and inducing target cell apoptosis. In addition, the release of chemokines and cytokines allows the recruitment and activation of immune cells, promoting the initiation of the adaptive immune response. Finaly, we also describe potential new therapeutic tools of Vγ9Vδ2 T cell-based immunotherapy that could be applied to emerging infections.

Innate immune response against HPV: Possible crosstalking with endocervical γδ T cells

Cervical carcinoma is significantly associated with the human papillomavirus (HPV). Persistent infection with high risk-HPV is necessary but not sufficient for the development of cervical cancer. It is not fully understood which immunological mechanisms lead to persistence in some patients. During the life cycle, HPV uses excellent immune evasion mechanisms. Keratinocytes, Langerhans cells (LC), dendritic cells (DC), tissue-resident macrophages, and intraepithelial gamma-delta T cells (γδ T cells) are cellular components of the mucosal immune defense of the female genital tract against HPV. γδ T cells, the prototype of unconventional T cells, play a major role in the first line defense of epithelial barrier protection. γδ T cells connect the innate and adaptive immunity and behave like a guardian of the epithelium against any form of damage such as trauma and infection. Any changes in γδ T cell distribution and functional capability may have a role in persistent HPV infection and cervical carcinogenesis in the early phase. Poor stimulation and maturation of APCs (LC/DC) might lead to persistent HPV infection which all point out pivotal role of γδ T cells in HPV persistence. If such an intriguing link is proven, γδ T cells can be used in potential therapeutics against HPV in infected patients.

Activation of Toll-Like Receptors Differentially Modulates Inflammation in the Human Reproductive Tract: Preliminary Findings

The female reproductive tract (FRT) is the main site of entry of sexually transmitted infections (STIs). Toll-like receptors (TLRs) that recognize pathogenic motifs are widely expressed in the FRT. TLR stimulation induces immune activation and local production of inflammatory mediators. In the FRT, this response should also be compatible with reproductive functions and symbiosis with host microbiota. With a view to develop efficient mucosal vaccines to prevent STI acquisition, the role of TLR ligands in the FRT needs to be explored. We have therefore investigated the cytokine profiles of the different compartments of the FRT (vagina, endocervix, ectocervix, and uterus) before and after stimulation of mononuclear cells from human tissue specimens. The comparison with PBMCs allowed us to highlight the FRT specificities. We first characterized the main immune cell populations in each compartment and observed that their distribution was different through the compartments. The CD45⁺ cells represented a maximum of 11% in the FRT in contrast to 96% in PBMCs. We identified two main populations among the CD45⁺ cells in the four compartments of the FRT: CD3⁺ T cells (CD4⁺ and CD8⁺) and CD14⁺ APCs. B cell populations (CD19⁺) were much less frequent than T cells in all the FRT regions and were equally distributed. NK CD56⁺ cells were detected in all compartments and were more abundant in the uterus. Stimulation of the mononuclear cells was then performed with TLR agonists: R848 for TLR7/8, Poly I:C for TLR3, LPS for TLR4 and ODN CpG for TLR9. Cytokine levels in unstimulated cultures of cells isolated from all FRT compartments were higher than in cultures of unstimulated PBMCs. In contrast, after stimulation with TLR agonists, cytokine responses induced by TLR agonists were moderate in the FRT and significantly lower than in PBMCs. These responses were varied with different TLR ligands and FRT compartments. The cytokine profile induced by TLR activation in the FRT supports the role of these tissues in genital anti-microbial immunity and in the control of inflammation while allowing maintenance of its reproductive function.

Impact of Standard Bacterial Vaginosis Treatment on the Genital Microbiota, Immune Milieu, and Ex Vivo Human Immunodeficiency Virus Susceptibility

BACKGROUND

Genital immunology is a key determinant of human immunodeficiency virus (HIV) susceptibility. Both factors are modulated by bacterial vaginosis (BV) and, to some extent, by Lactobacillus iners, the genital Lactobacillus spp. that predominates in African, Caribbean, and other Black (ACB) women. We conducted a clinical trial to assess the impact of oral metronidazole treatment on the genital immune parameters of HIV acquisition risks in Kenyan women with BV.

METHODS

The primary endpoint was ex vivo cervical CD4+ T-cell HIV susceptibility after 1 month; secondary endpoints included genital cytokine/chemokine levels, cervical immune cell populations, and the composition of the cervico-vaginal microbiota by 16S ribosomal RNA gene amplicon sequencing.

RESULTS

BV resolved (Nugent score ≤ 3) at 1 month in 20/45 participants, and cervical CD4+ T-cell HIV entry was moderately reduced in all participants, regardless of treatment outcome. Resolution of BV and reduced abundances of BV-associated gram-negative taxa correlated with reduced genital interleukin (IL)-1α/β. However, BV resolution and the concomitant colonization by Lactobacillus iners substantially increased several genital chemokines associated with HIV acquisition, including interferon-γ inducible protein (IP)-10, macrophage inflammatory protein (MIP)-3α, and monokine induced by gamma interferon (MIG). In an independent cohort of ACB women, most of whom were BV-free, vaginal chemokines were again closely linked with L. iners abundance, though not other Lactobacillus spp.

CONCLUSIONS

BV treatment reduced genital CD4+ T-cell HIV susceptibility and IL-1 levels, but dramatically increased the genital chemokines that may enhance HIV susceptibility; the latter effect was related to the restoration of an Lactobacillus iners-dominated microbiota. Further studies are needed before treatment of asymptomatic BV can be recommended for HIV prevention in ACB communities.

Shenfu injection prolongs survival and protects the intestinal mucosa in rats with sepsis by modulating immune response

BACKGROUND/AIMS

The aim of present study was to assess the protective effects of Shenfu injection (SI) on the intestinal mucosa and its regulation on the mucosal immune responses in rats with sepsis.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly divided into the sham, model, low-dose SI (LSF), and high-dose SI (HSF) groups. Sham animals underwent laparotomy only, whereas sepsis was modeled by cecal ligation and puncture in the remaining groups. At 2 h post-surgery, the LSF and HSF groups were intraperitoneally administered 5 and 20 mL/kg SI, respectively, whereas other animals with saline. At 12 h and 24 h post-surgery, eight rats per group were sacrificed, and blood and intestinal tissues were collected. The intestinal mucosa was analyzed by hematoxylin and eosin staining. Serum tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations, as well as secretory immunoglobulin A (sIgA) content in the intestinal mucosa, were evaluated by enzyme-linked immunosorbent assay. CD3 and γδT lymphocytes were quantified by flow cytometry. Animal survival until 72 h was also recorded.

RESULTS

Intestinal mucosal injury was significantly higher in model animals than in sham animals at postoperative 12 h and 24 h. Serum TNF-α and IL-6 levels were markedly increased, whereas sIgA and CD3 and γδT cell amounts were overtly decreased (p<0.01). The LSF and HSF rats showed lower mortality, intestinal mucosal injury, and serum TNF-α and IL-6 levels (p<0.05), as well as higher sIgA levels and CD3 and γδT cell amounts, than the model group (p<0.01), with a dose-dependent manner.

CONCLUSION

SI dose-dependently prolongs survival and protects the intestinal mucosa in rats with sepsis, possibly through strengthening innate immunity instead of acquired immunity.

Immune responses in the human female reproductive tract

Mucosal surfaces are key interfaces between the host and its environment, but also constitute ports of entry for numerous pathogens. The gut and lung mucosae act as points of nutrient and gas exchange, respectively, but the physiological purpose of the female reproductive tract (FRT) is to allow implantation and development of the fetus. Our understanding of immune responses in the FRT has traditionally lagged behind our grasp of the situation at other mucosal sites, but recently reproductive immunologists have begun to make rapid progress in this challenging area. Here, we review current knowledge of immune responses in the human FRT and their heterogeneity within and between compartments. In the commensal-rich vagina, the immune system must allow the growth of beneficial microbes, whereas the key challenge in the uterus is allowing the growth of the semi-allogeneic fetus. In both compartments, these objectives must be balanced with the need to eliminate pathogens. Our developing understanding of immune responses in the FRT will help us develop interventions to prevent the spread of sexually transmitted diseases and to improve outcomes of pregnancy for mothers and babies.

Mechanisms of sexually transmitted infection-induced inflammation in women: implications for HIV risk

INTRODUCTION

Globally, sexually transmitted infections (STI) affect >300 million people annually, and are a major cause of sexual and reproductive health complications in women. In this commentary, we describe how STIs interact with the immune and non-immune cells, both within and below the cervicovaginal mucosal barrier, to cause inflammation, which in turn has been associated with increased HIV acquisition risk.

DISCUSSION

STIs have a major impact on the female genital mucosa, which is an important biological and physical barrier that forms the first line of defence against invading microorganisms such as HIV. Pattern recognition of STI pathogens, by receptors expressed either on the cell surface or inside the cell, typically triggers inflammation at the mucosal barrier. The types of mucosal responses vary by STI, and can be asymptomatic or culminate in the formation of discharge, ulcers and/or warts. While the aim of this response is to clear the invading microbes, in many cases these responses are either evaded or cause pathology that impairs barrier integrity and increases HIV access to target cells in the sub-mucosa. In addition, innate responses to STIs can result in an increased number of immune cells, including those that are the primary targets of HIV, and may contribute to the association between STIs and increased susceptibility to HIV acquisition. Many of these cells are mediators of adaptive immunity, including tissue-resident cells that may also display innate-like functions. Bacterial vaginosis (BV) is another common cause of inflammation, and evidence for multiple interactions between BV, STIs and HIV suggest that susceptibility to these conditions should be considered in concert.

CONCLUSIONS

STIs and other microbes can induce inflammation in the genital tract, perturbing the normal robust function of the mucosal barrier against HIV. While the impact of STIs on the mucosal immune system and HIV acquisition is often under-appreciated, understanding their interactions of the infections with the immune responses play an important role in improving treatment and reducing the risk of HIV acquisition. The frequent sub-clinical inflammation associated with STIs underscores the need for better STI diagnostics to reverse the immunological consequences of infection.

Interplay among Vaginal Microbiome, Immune Response and Sexually Transmitted Viral Infections

The vaginal ecosystem is important for women's health and for a successful reproductive life, and an optimal host-microbial interaction is required for the maintenance of eubiosis. The vaginal microbiota is dominated by Lactobacillus species in the majority of women. Loss of Lactobacillus dominance promotes the colonization by anaerobic bacterial species with an increase in microbial diversity. Vaginal dysbiosis is a very frequent condition which affects the immune homeostasis, inducing a rupture in the epithelial barrier and favoring infection by sexually transmitted pathogens. In this review, we describe the known interactions among immune cells and microbial commensals which govern health or disease status. Particular attention is given to microbiota compositions which, through interplay with immune cells, facilitate the establishment of viral infections, such as Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV), Herpes Simplex Virus 2 (HSV2).

Meta-Analysis of The Prevalence of Genital Infections Among Hiv Carriers and Uninfected Women

Background & Aim:

The risk factors in acquiring genital co-infections associated with HIV infection still present many questions. We conducted a systematic review and meta-analysis to compare the prevalence of genital infection among HIV-infected and uninfected women.

Methods:

We searched PubMed, Web of Science, Scopus and Scielo for the relevant studies up until October 2017. Data were collected from the included studies and methodologically assessed. Odds ratios (OR) and 95% confidence intervals (CI) were pooled using fixed or random-effects models.

Results:

Thirty-six articles involving 23,863 women with retroviruses were included. HIV-infected women were significantly more diagnosed with the following genital infections:Herpes simplexvirus type 2 (HSV-2) (OR 3.70; 95% CI: 2.42–5.65),Neisseria gonorrhoeae(GC) (OR 4.18; 95% CI: 2.15-8.13),Chlamydia trachomatis(CT) (OR 2.25; 95% CI: 1.20-4.23) and Human papillomavirus (HPV) (OR 3.99, 95% CI: 3.35-4.75). There was no significant difference in the prevalence of bacterial vaginosis (OR 1.09; 95% CI: 0.91-1.30),Candida sp. (OR 1.51; 95% CI: 0.71-3.25),Treponema pallidum(OR 1.56; 95% CI: 1.00-2.45) andTrichomonas vaginalis(OR 1.00; 95% CI: 0.47-2.15).

Conclusion:

The prevalence of HPV, HSV-2, GC and CT genital infection was significantly higher among HIV-positive women.

Secretion of autoimmune antibodies in the human subcutaneous adipose tissue

The adipose tissue (AT) contributes to systemic and B cell intrinsic inflammation, reduced B cell responses and secretion of autoimmune antibodies. In this study we show that adipocytes in the human obese subcutaneous AT (SAT) secrete several pro-inflammatory cytokines and chemokines, which contribute to the establishment and maintenance of local and systemic inflammation, and consequent suboptimal immune responses in obese individuals, as we have previously shown. We also show that pro-inflammatory chemokines recruit immune cells expressing the corresponding receptors to the SAT, where they also contribute to local and systemic inflammation, secreting additional pro-inflammatory mediators. Moreover, we show that the SAT generates autoimmune antibodies. During the development of obesity, reduced oxygen and consequent hypoxia and cell death lead to further release of pro-inflammatory cytokines, “self” protein antigens, cell-free DNA and lipids. All these stimulate class switch and the production of autoimmune IgG antibodies which have been described to be pathogenic. In addition to hypoxia, we have measured cell cytotoxicity and DNA damage mechanisms, which may also contribute to the release of “self” antigens in the SAT. All these processes are significantly elevated in the SAT as compared to the blood. We definitively found that fat-specific IgG antibodies are secreted by B cells in the SAT and that B cells express mRNA for the transcription factor T-bet and the membrane marker CD11c, both involved in the production of autoimmune IgG antibodies. Finally, the SAT also expresses RNA for cytokines known to promote Germinal Center formation, isotype class switch, and plasma cell differentiation. Our results show novel mechanisms for the generation of autoimmune antibody responses in the human SAT and allow the identification of new pathways to possibly manipulate in order to reduce systemic inflammation and autoantibody production in obese individuals.

Toll-like receptors in immunity and inflammatory diseases: Past, present, and future

The immune system is a very diverse system of the host that evolved during evolution to cope with various pathogens present in the vicinity of environmental surroundings inhabited by multicellular organisms ranging from achordates to chordates (including humans). For example, cells of immune system express various pattern recognition receptors (PRRs) that detect danger via recognizing specific pathogen-associated molecular patterns (PAMPs) and mount a specific immune response. Toll-like receptors (TLRs) are one of these PRRs expressed by various immune cells. However, they were first discovered in the Drosophila melanogaster (common fruit fly) as genes/proteins important in embryonic development and dorso-ventral body patterning/polarity. Till date, 13 different types of TLRs (TLR1-TLR13) have been discovered and described in mammals since the first discovery of TLR4 in humans in late 1997. This discovery of TLR4 in humans revolutionized the field of innate immunity and thus the immunology and host-pathogen interaction. Since then TLRs are found to be expressed on various immune cells and have been targeted for therapeutic drug development for various infectious and inflammatory diseases including cancer. Even, Single nucleotide polymorphisms (SNPs) among various TLR genes have been identified among the different human population and their association with susceptibility/resistance to certain infections and other inflammatory diseases. Thus, in the present review the current and future importance of TLRs in immunity, their pattern of expression among various immune cells along with TLR based therapeutic approach is reviewed.

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TLRs are first described PRRs that revolutionized the biology of host-pathogen interaction and immune response

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The discovery of different TLRs in humans proved milestone in the field of innate immunity and inflammation

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The pattern of expression of all the TLRs expressed by human immune cells

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An association of various TLR SNPs with different inflammatory diseases

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Currently available drugs or vaccines based on TLRs and their future in drug targeting along with the role in reproduction, and regeneration

Vaginal microbiota and susceptibility to HIV

: Bacterial vaginosis, characterized by the replacement of the Lactobacillus-dominant microbiota with anaerobic bacteria and facultative Gram-negative rods, has been associated with adverse reproductive health outcomes including HIV acquisition. With the advent of newer molecular techniques, the vaginal microbiota can be investigated in more detail and the association with HIV examined more thoroughly. This review examines recent evidence suggesting that vaginal dysbiosis with increased microbial diversity, specific vaginal bacterial communities, and the presence and concentrations of some individual bacterial species, may increase HIV susceptibility. Potential mechanisms through which vaginal microbiota could impact HIV susceptibility are discussed. On the basis of the available data, this review finds that there is a modest, but growing, body of evidence linking vaginal microbiota to HIV susceptibility in women. The evidence could be strengthened through two main pathways. First, laboratory studies such as ex-vivo or animal experiments are needed to move from plausible mechanisms towards proven mechanisms that explain an effect of the vaginal microbiota on HIV susceptibility. Second, experimental evidence could directly test the hypothesis that sustaining optimal microbiota reduces HIV risk, though there are important obstacles to conducting such studies. Finally, this review examines strong evidence from a recent publication suggesting that deviations from an optimal vaginal microbiome, and particularly the presence of some bacterial communities with high relative abundance of Gardnerella vaginalis, reduces the efficacy of vaginal tenofovir-based microbicides.

The Role of Skin and Orogenital Microbiota in Protective Immunity and Chronic Immune-Mediated Inflammatory Disease

The skin and orogenital mucosae, which constitute complex protective barriers against infection and injuries, are not only the first to come into contact with pathogens but are also colonized by a set of microorganisms that are essential to maintain a healthy physiological environment. Using 16S ribosomal RNA metagenomic sequencing, scientists recognized that the microorganism colonization has greater diversity and variability than previously assumed. These microorganisms, such as commensal bacteria, affect the host’s immune response against pathogens and modulate chronic inflammatory responses. Previously, a single pathogen was thought to cause a single disease, but current evidence suggests that dysbiosis of the tissue microbiota may underlie the disease status. Dysbiosis results in aberrant immune responses at the surface and furthermore, affects the systemic immune response. Hence, understanding the initial interaction between the barrier surface immune system and local microorganisms is important for understanding the overall systemic effects of the immune response. In this review, we describe current evidence for the basis of the interactions between pathogens, microbiota, and immune cells on surface barriers and offer explanations for how these interactions may lead to chronic inflammatory disorders.

Differentiating Immune Cell Targets in Gut-Associated Lymphoid Tissue for HIV Cure

The single greatest challenge to an HIV cure is the persistence of latently infected cells containing inducible, replication-competent proviral genomes, which constitute only a small fraction of total or infected cells in the body. Although resting CD4+ T cells in the blood are a well-known source of viral rebound, more than 90% of the body's lymphocytes reside elsewhere. Many are in gut tissue, where HIV DNA levels per million CD4+ T cells are considerably higher than in the blood. Despite the significant contribution of gut tissue to viral replication and persistence, little is known about the cell types that support persistence of HIV in the gut; importantly, T cells in the gut have phenotypic, functional, and survival properties that are distinct from T cells in other tissues. The mechanisms by which latency is established and maintained will likely depend on the location and cytokine milieu surrounding the latently infected cells in each compartment. Therefore, successful HIV cure strategies require identification and characterization of the exact cell types that support viral persistence, particularly in the gut. In this review, we describe the seeding of the latent HIV reservoir in the gut mucosa; highlight the evidence for compartmentalization and depletion of T cells; summarize the immunologic consequences of HIV infection within the gut milieu; propose how the damaged gut environment may promote the latent HIV reservoir; and explore several immune cell targets in the gut and their place on the path toward HIV cure.

High Levels of Inflammatory Cytokines in the Reproductive Tract of Women with BV and Engaging in Intravaginal Douching: A Cross-Sectional Study of Participants in the Women Interagency HIV Study

High levels of inflammatory cytokines in the genital tract suggest mucosal vulnerability and increased risk of HIV and sexually transmitted infection (STI) acquisition. Intravaginal douching is associated with bacterial vaginosis (BV) in women in the United States, and both douching and BV are linked to HIV and STI acquisition. This study evaluates inflammatory cytokines in the genital tract to increase understanding of the effects of both BV and intravaginal douching to the vaginal mucosa. A cross-sectional study of participants in the Miami WIHS investigated 72 reproductive age women (45 HIV⁺ and 27 high-risk HIV^-) who completed intravaginal douching questionnaires and underwent collection of vaginal swabs and cervicovaginal lavages (CVLs). BV was assessed using the Nugent score. Inflammatory cytokines in the CVLs (interleukin [IL]-6, IL-8, IL-1α, IL-1β, soluble intracellular adhesion molecule-1 [sICAM-1], interferon [IFN]α2, chemokine C ligand 5 (CCL5), vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP1), tumor necrosis factor alpha (TNFα), and secretory leukocyte protease inhibitor [SLPI]) were measured. Fourteen (19%) women reported intravaginal douching; 24 (33%) had BV. BV, intravaginal douching, and HIV were associated with higher levels of inflammatory cytokines. After controlling for demographic and risk factors and HIV status, women who had BV and douched had higher levels of inflammatory cytokines than those without BV and who did not douche, or who only had BV or only douched. These findings suggest that BV and douching are associated with greater mucosal inflammation and may facilitate HIV acquisition and transmission. Although longitudinal studies are needed to determine temporal associations and causality, interventions to decrease rates of intravaginal douching and BV could significantly decrease women's risks of acquiring STIs and HIV and limit the spread of HIV.

Addressing intravaginal practices in women with HIV and at-risk for HIV infection, a mixed methods pilot study

Intravaginal practices (IVPs), include intravaginal cleansing (cleansing the inside of the vagina) or intravaginal insertion of products for hygiene, health or sexuality reasons. IVPs are associated with adverse female health outcomes, development of bacterial vaginosis, HIV acquisition and transmission. A mixed methods approach was used in this study to examine the prevalence of IVP, assess reasons for engagement, and perceptions of IVP among a sample of minority (African-American and Hispanic) women infected, or at-risk, for HIV in Miami, USA, a city with increasing numbers of sexually transmitted infections (STIs) and HIV. Three focus groups (total n=20) and quantitative assessments (n=72) were conducted with women infected or uninfected with HIV. In the qualitative assessments, most women reported engaging in both intravaginal cleansing and intravaginal insertion, and stated the main motivation for IVP was hygiene. The quantitative assessments confirmed that cleansing with water alone, soap with water or using commercial douches was common, as well as intravaginal insertion using a cloth or a rag in both HIV-infected and uninfected women. Women with HIV infection reported less use of water and water and soap for IVPs, and reported learning about the potential harm of IVP from their HIV health care providers. Despite their health risks, IVP appeared common in both HIV-infected and at-risk minority women, and interventions to decrease IVP could have important health implications among populations with high rates of IVP, STIs and HIV.

Isolation and Flow Cytometric Analysis of Human Endocervical Gamma Delta T Cells

The female reproductive tract (FRT) mucosal immune system serves as the first line of defense. Better knowledge of the genital mucosa is therefore essential for understanding pathogenicity of different pathogens including HIV. Gamma delta (GD) T cells are the prototype of 'unconventional' T cells and represent a relatively small subset of T cells defined by their expression of heterodimeric T-cell receptors (TCRs) composed of gamma and delta chains. This sets them apart from the classical and much better known CD4⁺ helper T cells and CD8⁺ cytotoxic T cells that are defined by alpha-beta TCRs. GD T cells often show tissue-specific localization and are enriched in epithelium. GD T cells orchestrate immune responses in inflammation, tumor surveillance, infectious disease, and autoimmunity. Here, we present a method to reproducibly isolate and analyze human endocervical intraepithelial GD T lymphocytes. We have used endocervical cytobrush samples from women participating in the Women's Interagency HIV Infection Study (WIHS). Knowledge about GD T cells interactions during conditions in which there is an insult to the vaginal mucosal could be applied to any clinical study in which mucosal vulnerability is addressed, including the development of vaginal microbicides.In addition, knowledge about mucosal GD T cell responses has potential for application of GD T cell-based immune therapy in treating infectious diseases.

Immune Regulation in Pregnancy: A Matter of Perspective?

The maternal immune system is complex and governed by multiple hormonal and metabolic factors, including those provided to the mother via the fetus. Understanding of the balance between maternal tolerance and protection of the fetus may require thinking from multiple theoretical approaches to the general problem of immune activation and tolerance. This article provides a brief review of the immune system, with aspects relevant to pregnancy. The references include reviews that expand on the elements discussed. The article also uses different models of immune system activation and tolerance to provide a theoretical understanding of the problem of maternal tolerance.

Immune Regulation in Pregnancy: A Matter of Perspective?

The maternal immune system is complex and governed by multiple hormonal and metabolic factors, including those provided to the mother via the fetus. Understanding of the balance between maternal tolerance and protection of the fetus may require thinking from multiple theoretical approaches to the general problem of immune activation and tolerance. This article provides a brief review of the immune system, with aspects relevant to pregnancy. The references include reviews that expand on the elements discussed. The article also uses different models of immune system activation and tolerance to provide a theoretical understanding of the problem of maternal tolerance.