Endogenous Transforming Growth Factor-? Inhibits Toll-Like Receptor Mediated Activation of Human Uterine Natural Killer Cells

The β6 Integrin Negatively Regulates TLR7-Mediated Epithelial Immunity via Autophagy During Influenza A Virus Infection

Integrins are essential surface receptors that sense extracellular changes to initiate various intracellular signaling cascades. The rapid activation of the epithelial-intrinsic β6 integrin during influenza A virus (IAV) infection has been linked to innate immune impairments. Yet, how β6 regulates epithelial immunity remains undefined. Here, we identify the role of β6 in mediating the Toll-like receptor 7 (TLR7) through the regulation of intracellular trafficking. We demonstrate that deletion of the β6 integrin in lung epithelial cells significantly enhances the TLR7-mediated activation of the type I interferon (IFN) response during homeostasis and respiratory infection. IAV-induced β6 facilitates TLR7 trafficking to lysosome-associated membrane protein (LAMP2a) components, leading to a reduction in endosomal compartments and associated TLR7 signaling. Our findings reveal an unappreciated role of β6-induced autophagy in influencing epithelial immune responses during influenza virus infection.

Benzo[a]pyrene immunogenetics and immune archetype reprogramming of lung

Overexposure to carcinogenic precursor, benzo[a]pyrene [BaP], modulates the lung immune microenvironment. The present review seeks to elucidate novel pathways behind the tumor effect of BaP in the lungs, emphasizing immunomodulatory mediators and immune cells. In this review, BaP reprograms lung immune microenvironment through modulating transforming growth factor-beta (TGF-β), programmed cell death 1 (PD-1), cytotoxic T lymphocyte antigen-4 (CTLA-4), Interleukin 12 (IL-12), indoleamine 2,3 dioxygenase (IDO), forkhead box protein P3 (FOXP3) and interferon-gamma (IFN-γ) levels. Moreover, BaP modulated lung immune cellular architecture such as dendritic cells, T cells, Tregs, macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs). All mentioned changes in immune architecture and mediators lead to the induction of lung cancer.

The COVID-19 pandemic: an increased risk of rheumatoid arthritis

COVID-19 is a respiratory infection similar to viral pneumonia and is caused by SARS-CoV-2. Chloroquine and hydroxychloroquine make up the major part of the treatment regimen for the management of COVID-19 infections, which are also commonly used in treatment of patients with malaria as well as autoimmune diseases like rheumatoid arthritis (RA). In this review, we analyzed the scientific evidences pertaining to any possible association of SARS-CoV-2 infection with RA. We thus believe that people predisposed to RA carry a higher infection risk than the general population both due to the iatrogenic effects of the RA related drug therapy. Thus COVID-19 pandemic may bring a higher risk of health emergency in complex diseases such as RA.

Regulation of the Immune Response by TGF-β: From Conception to Autoimmunity and Infection

Transforming growth factor β (TGF-β) is a pleiotropic cytokine involved in both suppressive and inflammatory immune responses. After 30 years of intense study, we have only begun to elucidate how TGF-β alters immunity under various conditions. Under steady-state conditions, TGF-β regulates thymic T-cell selection and maintains homeostasis of the naïve T-cell pool. TGF-β inhibits cytotoxic T lymphocyte (CTL), Th1-, and Th2-cell differentiation while promoting peripheral (p)Treg-, Th17-, Th9-, and Tfh-cell generation, and T-cell tissue residence in response to immune challenges. Similarly, TGF-β controls the proliferation, survival, activation, and differentiation of B cells, as well as the development and functions of innate cells, including natural killer (NK) cells, macrophages, dendritic cells, and granulocytes. Collectively, TGF-β plays a pivotal role in maintaining peripheral tolerance against self- and innocuous antigens, such as food, commensal bacteria, and fetal alloantigens, and in controlling immune responses to pathogens.

Immunity in urogenital protozoa

Innate and adaptive immunity play a significant role in urogenital infections. Innate immunity is provided by the epithelial cells and mucus lining along with acidic pH, which forms a strong physical barrier against the pathogens in female reproductive tract. Cells of innate immune system, antimicrobial peptides, cytokines, chemokines and adaptive immunity in the reproductive tract are evolved during infection, and a pro-inflammatory response is generated to fight against the invading pathogen Trichomonas vaginalis, a primary urogenital protozoa, the etiological agent of human trichomoniasis, a curable sexually transmitted infection. The involvement of the urogenital tract by other protozoal infections such as P. falciparum, Trypanosoma, Leishmania, Toxoplasma, Entamoeba histolytica and Acanthamoeba infection is rarely reported. Trichomonas induce pro-inflammatory and immunosuppressive responses in infected subjects. Multifactorial pathogenic mechanisms including parasite adherence, cysteine proteases, lipophosphoglycan, free radical, cytokine generation and Toll-like receptors appear to interplay with the induction of local and systemic immune responses that ultimately determine the outcome of the infection. However, the involvement of urogenital pathogen-specific immune mechanisms and effect of normal local resident flora on the outcome (symptomatic vs. asymptomatic) of infection are poorly understood. Moreover, immune interactions in trichomoniasis subjects co-infected with bacterial and viral pathogens need to be elucidated.

Mucosal immunity in the female genital tract, HIV/AIDS

Mucosal immunity consists of innate and adaptive immune responses which can be influenced by systemic immunity. Despite having been the subject of intensive studies, it is not fully elucidated what exactly occurs after HIV contact with the female genital tract mucosa. The sexual route is the main route of HIV transmission, with an increased risk of infection in women compared to men. Several characteristics of the female genital tract make it suitable for inoculation, establishment of infection, and systemic spread of the virus, which causes local changes that may favor the development of infections by other pathogens, often called sexually transmitted diseases (STDs). The relationship of these STDs with HIV infection has been widely studied. Here we review the characteristics of mucosal immunity of the female genital tract, its alterations due to HIV/AIDS, and the characteristics of coinfections between HIV/AIDS and the most prevalent STDs.

Regulation of mucosal immunity in the female reproductive tract: the role of sex hormones in immune protection against sexually transmitted pathogens

The immune system in the female reproductive tract (FRT) does not mount an attack against human immunodeficiency virus (HIV) or other sexually transmitted infections (STI) with a single endogenously produced microbicide or with a single arm of the immune system. Instead, the body deploys dozens of innate antimicrobials to the secretions of the FRT. Working together, these antimicrobials along with mucosal antibodies attack viral, bacterial, and fungal targets. Within the FRT, the unique challenges of protection against sexually transmitted pathogens coupled with the need to sustain the development of an allogeneic fetus, has evolved in such a way that sex hormones precisely regulate immune function to accomplish both tasks. The studies presented in this review demonstrate that estradiol (E2 ) and progesterone secreted during the menstrual cycle act both directly and indirectly on epithelial cells, fibroblasts and immune cells in the reproductive tract to modify immune function in a way that is unique to specific sites throughout the FRT. As presented in this review, studies from our laboratory and others demonstrate that the innate and adaptive immune systems are under hormonal control, that protection varies with the stage of the menstrual cycle and as such, is dampened during the secretory stage of the cycle to optimize conditions for fertilization and pregnancy. In doing so, a window of STI vulnerability is created during which potential pathogens including HIV enter the reproductive tract to infect host targets.

Role of the innate immunity in female reproductive tract

The mucosal immune system in the female reproductive tract (FRT) is well equipped to meet the sexually transmitted pathogens, allogeneic sperm, and the immunologically distinct fetus. Analysis of the FRT indicates that epithelial cells provide a physical barrier against pathogens and microbial infections as well as secretions containing anti-microbial peptides, cytokines, and chemokines which recruit and activate immune cells. Epithelial and immune cells confer protection in part through Toll-like receptors. The aim of this literature is to review the diverse components of the innate immune system, contributing to an exclusive protection system throughout the FRT.

Human endometrial endothelial cells generate distinct inflammatory and antiviral responses to the TLR3 agonist, Poly(I:C) and the TLR8 agonist, viral ssRNA

PROBLEM

Human endometrial endothelial cell (HEEC) innate immunity remains poorly characterized. Based on their direct contact with the circulation, HEECs are uniquely positioned to be exposed to viral infections. This study evaluated the innate immune response generated by HEECs after exposure to the TLR3 agonist, Poly(I:C) and the TLR8 agonist, viral ssRNA.

METHOD OF STUDY

HEECs were treated with or without Poly(I:C) or ssRNA. Culture supernatants were measured for cytokines by multiplex analysis. RNA was analyzed by qRT-PCR for type I interferons and antiviral factors.

RESULTS

Treatment of HEECs with Poly(I:C) rapidly upregulated the secretion of IL-2, IL-6, IL-8, IFN-γ, G-CSF, GM-CSF, MCP-1, MIP-1β, RANTES, and GRO-α after 12 hr, while ssRNA treatment induced the slower secretion of IL-6, IL-8, IFN-γ, G-CSF, VEGF, and GRO-α after 24 hr. Both viral components induced HEEC IFN-α and IFN-β expression. While treatment with Poly(I:C) induced APOBEC3G and OAS expression, treatment with ssRNA upregulated APOBEC3G and M×A mRNA.

CONCLUSION

Our findings demonstrate that HEECs can differentially sense and respond to viral components by generating distinct inflammatory and antiviral immune responses, indicating that these cells likely play an active role in the immune protection of the uterus toward viral infections.

Influence of lactic acid on endogenous and viral RNA-induced immune mediator production by vaginal epithelial cells

OBJECTIVE

To evaluate the influence of lactic acid on immune mediator release from vaginal epithelial cells.

METHODS

The human vaginal epithelial cell line, VK2/E6E7, was cultured in the presence or absence of physiological concentrations of lactic acid, and in the presence or absence of the viral Toll-like receptor 3 agonist, poly (inosinic acid:cytidylic acid). Supernatants were assayed by enzyme-linked immunosorbent assay (ELISA) for interleukin (IL)-1β, IL-6, IL-8, IL-23, transforming growth factor (TGF)-β and secretory leukocyte protease inhibitor.

RESULTS

Vaginal epithelial cells spontaneously released IL-1β (25.9 pg/mL), IL-8 (1.0 ng/mL), TGF-β (175 pg/mL), and secretory leukocyte protease inhibitor (33.8 ng/mL). Only TGF-β production was marginally enhanced (49%) by addition of lactic acid alone. Poly (inosinic acid:cytidylic acid) by itself stimulated the release of IL-6 (305 pg/mL) and enhanced IL-8 production (2.8 ng/mL). The combination of poly (inosinic acid:cytidylic acid) and lactic acid markedly increased IL-8 production (5.0 ng/mL) and induced the release of IL-1β (96.2 pg/mL). The poly (inosinic acid:cytidylic acid)-mediated lactic acid effect on IL-1β and IL-8 release was abrogated when the lactic acid was neutralized or if acetic acid was substituted for lactic acid.

CONCLUSION

Lactic acid enhances the release of selective mediators from vaginal epithelial cells and stimulates antiviral immune responses.

Gimme shelter: the immune system during pregnancy

Antigen-presenting molecules vary between individuals of the same species, making it more difficult for pathogens to evade immune recognition and spread through the whole population. As a result of this genetic diversity, transplants between individuals are recognized as foreign and are rejected. This alloreactivity turns placental viviparity into a major immunological challenge. The maternal immune system has to balance the opposing needs of maintaining robust immune reactivity to protect both mother and fetus from invading pathogens, while at the same time tolerating highly immunogenic paternal alloantigens in order to sustain fetal integrity. Regulatory T cells are responsible for the establishment of tolerance by modulating the immune response, and uterine natural killer cells direct placentation by controlling trophoblast invasion. A variety of other cell types, including decidual stromal cells, dendritic cells, and immunomodulatory multipotent mesenchymal stromal cells, are found at the fetal-maternal interface. These cells conspire to establish a suitable environment for fetal development without compromising systemic immunity. Defects in any of these components can lead to gestational failure despite successful fertilization.

Diversion of the immune response to Neisseria gonorrhoeae from Th17 to Th1/Th2 by treatment with anti-transforming growth factor β antibody generates immunological memory and protective immunity

The immune response to Neisseria gonorrhoeae is poorly understood, but its extensive antigenic variability and resistance to complement are thought to allow it to evade destruction by the host’s immune defenses. We propose that N. gonorrhoeae also avoids inducing protective immune responses in the first place. We previously found that N. gonorrhoeae induces interleukin-17 (IL-17)-dependent innate responses in mice and suppresses Th1/Th2-dependent adaptive responses in murine cells in vitro through the induction of transforming growth factor β (TGF-β). In this study using a murine model of vaginal gonococcal infection, mice treated with anti-TGF-β antibody during primary infection showed accelerated clearance of N. gonorrhoeae, with incipient development of Th1 and Th2 responses and diminished Th17 responses in genital tract tissue. Upon secondary reinfection, mice that had been treated with anti-TGF-β during primary infection showed anamnestic recall of both Th1 and Th2 responses, with the development of antigonococcal antibodies in sera and secretions, and enhanced resistance to reinfection. In mouse knockout strains defective in Th1 or Th2 responses, accelerated clearance of primary infection due to anti-TGF-β treatment was dependent on Th1 activity but not Th2 activity, whereas resistance to secondary infection resulting from anti-TGF-β treatment during primary infection was due to both Th1- and Th2-dependent memory responses. We propose that N. gonorrhoeae proactively elicits Th17-driven innate responses that it can resist and concomitantly suppresses Th1/Th2-driven specific adaptive immunity that would protect the host. Blockade of TGF-β reverses this pattern of host immune responsiveness and facilitates the emergence of protective antigonococcal immunity.

Pathogen-host interactions during infectious disease are conventionally thought of as two-way reactions, that of the host against the pathogen and vice versa, with the outcome dependent on which one ultimately prevails. We propose that Neisseria gonorrhoeae, a pathogen that has become extremely well adapted to its exclusive human host, proactively directs the manner in which the host responds in ways that are beneficial to its own survival but detrimental to the host. Gonorrhea is a widely prevalent sexually transmitted infection, and naturally occurring gonococcal strains are becoming resistant to most available antibiotics, yet no effective vaccine has been developed. These new insights into the immune response to N. gonorrhoeae should lead to novel therapeutic strategies and facilitate new approaches to vaccine development.

TLRs, macrophages, and NK cells: our understandings of their functions in uterus and ovary

Inflammation involves multiple changes in many aspects of immune system. Interactions between immune system and female reproductive system strongly impact fertility and reproductive health in general. Many normal events of female reproduction system including ovulation, menstruation, implantation and labor onset are considered as inflammatory process. Emerging evidence reveals that three components of immune system that are critical to initiate and resolve inflammation, Toll-like receptors (TLRs), macrophages, and natural killer (NK) cells, play important roles not only to provide protection against infections by exogenous pathogens but also to regulate essential functions of uterus and ovary. This review will briefly summarize our understanding of the functions of TLRs, macrophages and NK cells in uterus and ovary.

Lipopolysaccharide (LPS)-induced Interferon (IFN)-gamma production by decidual mononuclear cells (DMNC) is interleukin (IL)-2 and IL-12 dependent

PROBLEM

Th1-shifted immune response is believed to be harmful for successful pregnancy because of activation of maternal cytotoxic T lymphocytes and natural killer cells. However, its effects on Toll-like receptor (TLR)-mediated innate immune response are so far unknown and this study has been undertaken to address the issue.

METHOD OF STUDY

decidual tissues were obtained from 16 pregnant women undergoing elective termination during the first trimester pregnancy for socioeconomic reasons. Decidual Mononuclear Cells (DMNC) were stimulated with suboptimal doses of IL-2 and IL-12 with/without LPS, considered to be a TLR4 ligand, for 48 hr. Productions of IFN-γ and tumor necrosis factor (TNF)-α in culture supernatant were measured with ELISA.

RESULTS

(i) IFN-γ production was induced with LPS alone which was strongly up-regulated in the presence of IL-2 and IL-12. (ii) TNF-α was also induced by LPS but was not affected by the presence of IL-2 and IL-12.

CONCLUSION

IL-2 and IL-12 up-regulated the production of IFN-γ in DMNC through increasing their susceptibility to LPS. TNF-α production is independent of such a mechanism.

Innate and adaptive immunity at mucosal surfaces of the female reproductive tract: stratification and integration of immune protection against the transmission of sexually transmitted infections

This review examines the multiple levels of pre-existing immunity in the upper and lower female reproductive tract. In addition, we highlight the need for further research of innate and adaptive immune protection of mucosal surfaces in the female reproductive tract. Innate mechanisms include the mucus lining, a tight epithelial barrier and the secretion of antimicrobial peptides and cytokines by epithelial and innate immune cells. Stimulation of the innate immune system also serves to bridge the adaptive arm resulting in the generation of pathogen-specific humoral and cell-mediated immunity. Less understood are the multiple components that act in a coordinated way to provide a network of ongoing protection. Innate and adaptive immunity in the human female reproductive tract are influenced by the stage of menstrual cycle and are directly regulated by the sex steroid hormones, progesterone and estradiol. Furthermore, the effect of hormones on immunity is mediated both directly on immune and epithelial cells and indirectly by stimulating growth factor secretion from stromal cells. The goal of this review is to focus on the diverse aspects of the innate and adaptive immune systems that contribute to a unique network of protection throughout the female reproductive tract.

Tolerance and protection against infection in the genital tract

The genital tract is a unique immunological environment that must support the reproductive function and resist infection. Particularly in the female tract, immunoregulatory and immunosuppressive activities that permit the growth of the fetus create an environment that can readily be exploited by microbes that have become well-adapted to this location. Cellular and molecular mediators of immune responses differ from those found at other mucosal surfaces. Mechanisms of immune response induction and delivery, as well as immune effector functions at the genital mucosae need to be considered in the development of vaccines against infections of the genital tract.

Pattern recognition via the toll-like receptor system in the human female genital tract

The mucosal surface of the female genital tract is a complex biosystem, which provides a barrier against the outside world and participates in both innate and acquired immune defense systems. This mucosal compartment has adapted to a dynamic, non-sterile environment challenged by a variety of antigenic/inflammatory stimuli associated with sexual intercourse and endogenous vaginal microbiota. Rapid innate immune defenses against microbial infection usually involve the recognition of invading pathogens by specific pattern-recognition receptors recently attributed to the family of Toll-like receptors (TLRs). TLRs recognize conserved pathogen-associated molecular patterns (PAMPs) synthesized by microorganisms including bacteria, fungi, parasites, and viruses as well as endogenous ligands associated with cell damage. Members of the TLR family, which includes 10 human TLRs identified to date, recognize distinct PAMPs produced by various bacterial, fungal, and viral pathogens. The available literature regarding the innate immune system of the female genital tract during human reproductive processes was reviewed in order to identify studies specifically related to the expression and function of TLRs under normal as well as pathological conditions. Increased understanding of these molecules may provide insight into site-specific immunoregulatory mechanisms in the female reproductive tract.

Sex hormone regulation of innate immunity in the female reproductive tract: the role of epithelial cells in balancing reproductive potential with protection against sexually transmitted pathogens

The immune system in the female reproductive tract (FRT) does not mount an attack against HIV or other sexually transmitted infections (STI) with a single endogenously produced microbicide or with a single arm of the immune system. Instead, the body deploys dozens of innate antimicrobials to the secretions of the female reproductive tract. Working together, these antimicrobials along with mucosal antibodies attack many different viral, bacterial and fungal targets. Within the FRT, the unique challenges of protection against sexually transmitted pathogens coupled with the need to sustain the development of an allogeneic fetus have evolved in such a way that sex hormones precisely regulate immune function to accomplish both tasks. The studies presented in this review demonstrate that estradiol and progesterone secreted during the menstrual cycle act both directly and indirectly on epithelial cells and other immune cells in the reproductive tract to modify immune function in a way that is unique to specific sites throughout the FRT. As presented in this review, studies from our laboratory and others demonstrate that the innate immune response is under hormonal control, varies with the stage of the menstrual cycle, and as such is suppressed at mid-cycle to optimize conditions for successful fertilization and pregnancy. In doing so, a window of STI vulnerability is created during which potential pathogens including HIV enter the reproductive tract to infect host targets.

UNK cells: their role in tissue re-modelling and preeclampsia

In different species of mammal, uterine natural killer (uNK) cells are massively recruited and presented at the fetal maternal interface with a spatio-temporal pattern, and regarded as a constructive element to support reproductive development. Recent insights highlight the uNK cells activation, function and interaction with local compartments, which all contribute to the initiation of vascular structural changes. New trends of uNK cells research will benefit the diagnosis, management and test treatment strategy of preeclampsia. Furthermore, we suggest that more efforts and specific studies are needed to further explore the role of uNK cells at the unique micro-environment.

Toll‐like receptors in the gonads and reproductive tract: emerging roles in reproductive physiology and pathology

Interactions between the immune system and reproductive system have important consequences for fertility and reproductive health in general. There is increasing evidence that many of the interactions between the immune and reproductive systems involve the Toll-like receptors (TLRs). While there is no doubt that TLRs are important in providing protection against infection in the reproductive tract, there is increasing evidence for the involvement of TLRs in more basic pathology and physiology of reproduction. In the female, TLRs have been implicated in critical aspects of ovarian, endometrial and placental function, as well as in ovarian cancer, pelvic inflammatory disease, intrauterine growth restriction, pre-eclampsia and preterm birth. In the male, TLRs appear to play a role in the control of testicular steroidogenesis and spermatogenesis in disease and, potentially, during normal function, as well. Recent studies also have begun to highlight the role of various TLRs in the aetiology of prostatitis and prostatic cancer. Given the nascent state of knowledge concerning this important area, it is clear that more studies are needed, which should provide valuable new insights into the biology of the TLRs and reproductive function in general.