Expression profiling of human milk derived exosomal microRNAs and their targets in HIV-1 infected mothers.

Despite the use of antiretroviral therapy (ART) in HIV-1 infected mothers approximately 5% of new HIV-1 infections still occur in breastfed infants annually, which warrants for the development of novel strategies to prevent new HIV-1 infections in infants. Human milk (HM) exosomes are highly enriched in microRNAs (miRNAs), which play an important role in neonatal immunity. Furthermore, HM exosomes from healthy donors are known to inhibit HIV-1 infection and transmission; however, the effect of HIV-1 on HM exosomal miRNA signatures remains unknown.

TLR10 Senses HIV-1 Proteins and Significantly Enhances HIV-1 Infection.

Toll-like receptors (TLRs) play a crucial role in innate immunity and provide a first line of host defense against invading pathogens. Of the identified human TLRs, TLR10 remains an orphan receptor whose ligands and functions are poorly understood. In the present study, we sought to evaluate the level of TLR10 expression in breast milk (BM) and explore its potential function in the context of HIV-1 infection.

Breastfeeding mitigates the effects of maternal HIV on infant infectious morbidity in the Option B+ era.

Objective: The effects of in-utero HIV-exposure on infectious morbidity and mortality in settings with universal maternal treatment and high breastfeeding rates are unclear. Further, the benefits of exclusive feeding options have not been assessed in the Option B+ era. We investigated these in two African settings with high breastfeeding uptake and good HIV treatment infrastructure during the first year of life.

Breastfeeding Behaviors and the Innate Immune System of Human Milk: Working Together to Protect Infants against Inflammation, HIV-1, and Other Infections.

The majority of infants' breastfeeding from their HIV-infected mothers do not acquire HIV-1 infection despite exposure to cell-free virus and cell-associated virus in HIV-infected breast milk. Paradoxically, exclusive breastfeeding regardless of the HIV status of the mother has led to a significant decrease in mother-to-child transmission (MTCT) compared with non-exclusive breastfeeding. Although it remains unclear how these HIV-exposed infants remain uninfected despite repeated and prolonged exposure to HIV-1, the low rate of transmission is suggestive of a multitude of protective, short-lived bioactive innate immune factors in breast milk.

Insights into Soluble Toll-Like Receptor 2 as a Downregulator of Virally Induced Inflammation.

The ability to distinguish pathogens from self-antigens is one of the most important functions of the immune system. However, this simple self versus non-self assignment belies the complexity of the immune response to threats. Immune responses vary widely and appropriately according to a spectrum of threats and only recently have the mechanisms for controlling this highly textured process emerged.

Afri-Can Forum 2 : Johannesburg, South Africa. 16-18 February 2015.

A1 Introduction to the 2nd synchronicity forum of GHRI/CHVI-funded Canadian and African HIV prevention and vaccine teams O1 Voluntary medical male circumcision for prevention of heterosexual transmission of HIV in adult males in Soweto: What do indicators and incidence rate show? Hillary Mukudu, Neil Martinson, Benn Sartorius O2 Developing a peer-led community mobilization program for sex workers in Soweto: HIV risk and demographics Jenny Coetzee, Janan Dietrich, Kgaugelo Mokgatswana, Rachel Jewkes, Glenda E. Gray O3 Salient beliefs about adherence: A qualitative survey conducted as part of the demonstration study on "treatment as prevention" (TasP) and "pre-exposure prophylaxis" (PrEP) among female sex workers (FSWS) in Cotonou, Benin Marylène Dugas, Luc Béhanzin, Fernand A. Guédou, Marie-Pierre Gagnon, Michel Alary O4 Relative perception of risk as a driver of unsafe sexual practices among key populations: Cases of fisherfolk and women and their partners involved in multiple sexual partnerships in Uganda Rwamahe Rutakumwa, Martin Mbonye, Thadeus Kiwanuka, Sarah Nakamanya, Richard Muhumuza, Winfred Nalukenge, Janet Seeley O5 Exploring the acceptability of new biomedical HIV prevention technologies among MSM, adolescents and heterosexual adults in South Africa Millicent Atujuna, Melissa Wallace, Ben Brown, Linda Gail Bekker, Peter A.

HIV-1 Structural Proteins Serve as PAMPs for TLR2 Heterodimers Significantly Increasing Infection and Innate Immune Activation.

Immune activation is critical to HIV infection and pathogenesis; however, our understanding of HIV innate immune activation remains incomplete. Recently we demonstrated that soluble TLR2 (sTLR2) physically inhibited HIV-induced NFκB activation and inflammation, as well as HIV-1 infection. In light of these findings, we hypothesized that HIV-1 structural proteins may serve as pathogen-associated molecular patterns (PAMPs) for cellular TLR2 heterodimers.

Soluble toll-like receptor 2 is significantly elevated in HIV-1 infected breast milk and inhibits HIV-1 induced cellular activation, inflammation and infection.

Objectives: We previously demonstrated that immunodepletion of soluble Toll-like receptor 2 (sTLR2) from human breast milk significantly increased HIV infection in vitro. The aims of this study were to characterize sTLR2 levels in breast milk from HIV-infected and uninfected women, and identify a mechanism by which sTLR2 inhibits HIV-induced cellular activation and infection.

Design: Blinded studies of breast milk from HIV-infected and uninfected Nigerian and Canadian women were evaluated for levels of sTLR2, proinflammatory cytokines and viral antigenemia.

Anti-HIV-1 activity of elafin depends on its nuclear localization and altered innate immune activation in female genital epithelial cells.

Elafin (E) and its precursor trappin-2 (Tr) are alarm antiproteases with antimicrobial and immunomodulatory activities. Tr and E (Tr/E) have been associated with HIV-1 resistance. We recently showed that Tr/E reduced IL-8 secretion and NF-κB activation in response to a mimic of viral dsRNA and contributed to anti-HIV activity of cervicovaginal lavage fluid (CVL) of HIV-resistant (HIV-R) commercial sex workers (CSWs).

Trappin-2/elafin modulate innate immune responses of human endometrial epithelial cells to PolyI:C.

Background: Upon viral recognition, innate and adaptive antiviral immune responses are initiated by genital epithelial cells (ECs) to eradicate or contain viral infection. Such responses, however, are often accompanied by inflammation that contributes to acquisition and progression of sexually transmitted infections (STIs). Hence, interventions/factors enhancing antiviral protection while reducing inflammation may prove beneficial in controlling the spread of STIs.

War and peace between WAP and HIV: role of SLPI, trappin-2, elafin and ps20 in susceptibility to HIV infection.

Despite tremendous advances in our understanding of HIV/AIDS since the first cases were reported 30 years ago, we are still a long way from understanding critical steps of HIV acquisition, pathogenesis and correlates of protection. Our new understanding of the importance of the mucosa as a target for HIV infection, as well as our recent observations showing that altered expression and responses of innate pattern recognition receptors are significantly associated with pathogenesis and resistance to HIV infection, indicate that correlates of immunity to HIV are more likely to be associated with mucosal and innate responses. Most of the heterosexual encounters do not result in productive HIV infection, suggesting that the female genital tract is protected against HIV by innate defence molecules, such as antiproteases, secreted mucosally.

Herpes simplex virus type 2 virion host shutoff protein suppresses innate dsRNA antiviral pathways in human vaginal epithelial cells.

Viruses that establish persistent infections have evolved numerous strategies to evade host innate antiviral responses. We functionally assessed the role of herpes simplex virus type 2 (HSV-2) virion host shutoff (vhs) protein on innate immune sensing pathways in human vaginal epithelial cells (VK2 ECs). Infection of cells with wild-type (WT) HSV-2 significantly decreased expression of innate immune sensors of viral infection, Toll-like receptor (TLR)2, TLR3, retinoic acid inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (Mda-5), relative to cells infected with a mutant that lacks vhs (vhsB) or mock-infected cells.

IL-15 and type I interferon are required for activation of tumoricidal NK cells by virus-infected dendritic cells.

There is increasing evidence that natural killer (NK) cells play an important role in antitumor immunity following dendritic cell (DC) vaccination. Little is known, however, about the optimal stimulation of DCs that favors NK activation in tumor-bearing hosts. In this study, we demonstrate that treatment with toll-like receptor (TLR) ligands and infection with a mutant vesicular stomatitis virus (VSV-ΔM51) both induced DC maturation.

Multiple tandem copies of conserved gp41 epitopes incorporated in gag virus-like particles elicit systemic and mucosal antibodies in an optimized heterologous vector delivery regimen.

Induction of neutralizing antibodies to prevent HIV infection, especially at the mucosa, is a critical goal of future vaccines. In this study, we have designed chimeric HIV-gag virus-like particles (VLPs) that contain multiple copies of the two highly conserved gp41 membrane-proximal external region (MPER) epitopes, ELDKWA and NWFDIT, with the objective of generating high titers of MPER-specific antibodies. We have shown that the implementation of optimized vector design, delivery regimens and appropriate delivery methods is critical to significantly increase epitope-specific antibody titers.

Intravaginal infection with herpes simplex virus type-2 (HSV-2) generates a functional effector memory T cell population that persists in the murine genital tract.

Although the female genital tract is the main portal of entry for sexually transmitted infections in women, we still have limited understanding of the generation, maintenance and characteristics of memory T cells in the local tissue. Here, we utilized a mouse model of intravaginal HSV-2 infection and tetramers against the immunodominant HSV glycoprotein B epitope recognized by CD8+ T cells to examine the generation, maintenance and characteristics of anti-HSV memory T cells in the genital tract following acute infection. Our results show that the highest percentage of HSVgB-specific CD8+ T cells was found in the genital tract compared to the spleen or iliac lymphnode.

Development of functional human NK cells in an immunodeficient mouse model with the ability to provide protection against tumor challenge.

Studies of human NK cells and their role in tumor suppression have largely been restricted to in vitro experiments which lack the complexity of whole organisms, or mouse models which differ significantly from humans. In this study we showed that, in contrast to C57BL/6 Rag2(-/-)/gamma(c) (-/-) and NOD/Scid mice, newborn BALB/c Rag2(-/-)/gamma(c) (-/-) mice can support the development of human NK cells and CD56+ T cells after intrahepatic injection with hematopoietic stem cells. The human CD56(+) cells in BALB/c Rag2(-/-)/gamma(c) (-/-) mice were able to produce IFN-gamma in response to human IL-15 and polyI:C.

Mucosal innate and adaptive immune responses against herpes simplex virus type 2 in a humanized mouse model.

Genital herpes, caused by herpes simplex virus type 2 (HSV-2), is one of the most prevalent sexually transmitted diseases worldwide and a risk factor for acquiring human immunodeficiency virus. Although many vaccine candidates have shown promising results in animal models, they have failed to be effective in human trials. In this study, a humanized mouse strain was evaluated as a potential preclinical model for studying human immune responses to HSV-2 infection and vaccination.

HIV-1 RNA dysregulates the natural TLR response to subclinical endotoxemia in Kenyan female sex-workers.

Background: Subclinical endotoxemia has been reported in HIV-1 infected persons and may drive systemic immune activation and pathogenesis. Proinflammatory responsiveness to endotoxin (LPS) is mediated by Toll-like receptor 4 (TLR4). We therefore examined the association between plasma LPS levels, HIV RNA, and TLR4 expression and cytokine responses in the blood of HIV infected and uninfected participants in a cohort of female sex-workers in Kenya.

Differential induction of innate anti-viral responses by TLR ligands against Herpes simplex virus, type 2, infection in primary genital epithelium of women.

Genital epithelial cells (GECs) are the first line of mucosal defense against sexually transmitted infections. We exploited the ability of GECs to mount innate immune responses, by using TLR ligands to induce anti-viral activity against Herpes simplex virus, type 2 (HSV-2). Primary cultures of GECs were grown to confluent, polarized monolayers and found to express different levels of mRNA for TLR1-10.

Tweaking Innate Immunity: the Promise of Innate Immunologicals As Anti-infectives.

New and exciting insights into the importance of the innate immune system are revolutionizing our understanding of immune defense against infections, pathogenesis, and the treatment and prevention of infectious diseases. The innate immune system uses multiple families of germline-encoded pattern recognition receptors (PRRs) to detect infection and trigger a variety of antimicrobial defense mechanisms. PRRs are evolutionarily highly conserved and serve to detect infection by recognizing pathogen-associated molecular patterns that are unique to microorganisms and essential for their survival.

Toll-like receptor expression and responsiveness are increased in viraemic HIV-1 infection.

Objectives: Toll-like receptors (TLR) are important in pathogen recognition and may play a role in HIV disease. We evaluated the effect of chronic untreated and treated HIV-1 infection on systemic TLR expression and TLR signalling.

Methods: Two hundred HIV-infected and uninfected women from a Kenya cohort participated in the studies.

Susceptibility of human female primary genital epithelial cells to herpes simplex virus, type-2 and the effect of TLR3 ligand and sex hormones on infection.

Genital epithelial cells (ECs) are the first line of defense that sexually transmitted viruses encounter. The mechanism of viral pathogenesis in these cells is not well understood. Here, we show that a primary cell culture model from human reproductive tract tissues can be used as a novel ex vivo model in examining the interaction of herpes simplex virus, type 2 (HSV-2), with female genital mucosa.