Seminal plasma components stimulate interleukin-8 and interleukin-10 release

A synthetic review: natural history of amniote reproductive modes in light of comparative evolutionary genomics

There is a current lack of consensus on whether the ancestral parity mode was oviparity (egg-laying) or viviparity (live-birth) in amniotes and particularly in squamates (snakes, lizards, and amphisbaenids). How transitions between parity modes occur at the genomic level has primary importance for how science conceptualises the origin of amniotes, and highly variable parity modes in Squamata. Synthesising literature from medicine, poultry science, reproductive biology, and evolutionary biology, I review the genomics and physiology of five broad processes (here termed the 'Main Five') expected to change during transitions between parity modes: eggshell formation, embryonic retention, placentation, calcium transport, and maternal-fetal immune dynamics. Throughout, I offer alternative perspectives and testable hypotheses regarding proximate causes of parity mode evolution in amniotes and squamates. If viviparity did evolve early in the history of lepidosaurs, I offer the nucleation site hypothesis as a proximate explanation. The framework of this hypothesis can be extended to amniotes to infer their ancestral state. I also provide a mechanism and hypothesis on how squamates may transition from viviparity to oviparity and make predictions about the directionality of transitions in three species. After considering evidence for differing perspectives on amniote origins, I offer a framework that unifies (i) the extended embryonic retention model and (ii) the traditional model which describes the amniote egg as an adaptation to the terrestrial environment. Additionally, this review contextualises the origin of amniotes and parity mode evolution within Medawar's paradigm. Medawar posited that pregnancy could be supported by immunosuppression, inertness, evasion, or immunological barriers. I demonstrate that this does not support gestation or gravidity across most amniotes but may be an adequate paradigm to explain how the first amniote tolerated internal fertilization and delayed egg deposition. In this context, the eggshell can be thought of as an immunological barrier. If serving as a barrier underpins the origin of the amniote eggshell, there should be evidence that oviparous gravidity can be met with a lack of immunological responses in utero. Rare examples of two species that differentially express very few genes during gravidity, suggestive of an absent immunological reaction to oviparous gravidity, are two skinks Lampropholis guichenoti and Lerista bougainvillii. These species may serve as good models for the original amniote egg. Overall, this review grounds itself in the historical literature while offering a modern perspective on the origin of amniotes. I encourage the scientific community to utilise this review as a resource in evolutionary and comparative genomics studies, embrace the complexity of the system, and thoughtfully consider the frameworks proposed.

Contribution of the seminal microbiome to paternal programming

The field of Developmental Origins of Health and Disease has primarily focused on maternal programming of offspring health. However, emerging evidence suggests that paternal factors, including the seminal microbiome, could potentially play important roles in shaping the developmental trajectory and long-term offspring health outcomes. Historically, the microbes present in the semen were regarded as inherently pathogenic agents. However, this dogma has recently been challenged by the discovery of a diverse commensal microbial community within the semen of healthy males. In addition, recent studies suggest that the transmission of semen-associated microbes into the female reproductive tract during mating has potentials to not only influence female fertility and embryo development but could also contribute to paternal programming in the offspring. In this review, we summarize the current knowledge on the seminal microbiota in both humans and animals followed by discussing their potential involvement in paternal programming of offspring health. We also propose and discuss potential mechanisms through which paternal influences are transmitted to offspring via the seminal microbiome. Overall, this review provides insights into the seminal microbiome-based paternal programing, which will expand our understanding of the potential paternal programming mechanisms which are currently focused primarily on the epigenetic modifications, oxidative stresses, and cytokines.

Effects of natural mating, artificial insemination and intravaginal deposition of raw semen or seminal plasma on vaginal and uterine blood flow in German Holstein cows

AIM

The present study was performed to characterize and compare the perfusion of vaginal and uterine arteries after challenging the reproductive tract of dairy cows via natural mating, artificial insemination (AI), or intravaginal deposition (vaginal fundus) of different biological fluids or a placebo.

MATERIALS AND METHODS

In a double-blind study, six German Holstein cows were administered PGF2α during dioestrus and 48 h later treated with GnRH. Intravaginal or intrauterine treatments were carried out 12 h after GnRH was administered. Animals served as their controls, using a cross-over design with an interval of 14 days between experiments. The experimental animals were allocated to receive the following treatments: natural mating (N), intrauterine artificial insemination (A), intravaginal deposition (vaginal fundus) of 6 mL raw semen (R) or 6 mL seminal plasma (S), and compared to their controls [control 1: 6 mL placebo (P: physiological saline); control 2: no treatment (C)). Corresponding time intervals were chosen for the untreated control oestrus. Blood flow volume (BFV) in the uterine (u) and vaginal (v) arteries ipsilateral to the ovary bearing the preovulatory follicle was determined using transrectal Doppler sonography.

RESULTS

All animals exhibited oestrus and ovulated between 30 and 36 h after GnRH. Transient increases (P < 0.05) in vaginal blood flow occurred between 3 and 12 h following mating as well as 3 to 9 h after deposition of raw semen and seminal plasma, respectively. The most distinct increases (199%) in vBFV occurred 6 h after mating compared to values immediately before mating (= time 0 h). Neither AI nor deposition of a placebo into the vagina affected vBFV (P > 0.05). Only mating and deposition of either raw semen, seminal plasma or AI increased uBFV (P < 0.003). The greatest rise in uBFV occurred after natural mating. Maximum uBFV values were detected 9 h after mating when values were 79% greater (P < 0.05) than at 0 h.

CONCLUSIONS

The natural mating, deposition of raw semen or seminal plasma and conventional AI affect vaginal and/or uterine blood flow to different degrees. The factors responsible for these alterations in blood flow and their effects on fertility remain to be clarified in future studies.

Changes in interleukin-2, -4, -6 and -8 expression in the postovulatory sow endometrium after artificial insemination based on conceived or failed to conceive

The establishment and maintenance of a pregnancy requires proper interaction between the endocrine and immune systems in the uterus. Therefore, it is crucial to understand how changes in endometrial cytokine levels facilitate reproduction. This study aimed to investigate how representative cytokines sequentially changed in the endometrium and whether conception could be attributed to these changes. In this study, artificial insemination was performed twice in 160 sows and ovulation was examined every 3 h using transrectal ultrasonography. Uterine endometrial tissues were obtained via repeated biopsies at 2, 4, 6, 8, 12, 16, and 20 h after ovulation and interleukin (IL)-2, IL-4, IL-6, and IL-8 expression was examined using real-time polymerase chain reaction. The conception rate was 91.9%. The IL-2 levels showed no differences in conception or time. The expression peaks of IL-4 and IL-6 were delayed in sows that failed to conceive within 4-6 h and 2 h, respectively, compared to those that did conceive. In sows that conceived, IL-8 was highest after 2 h, and no difference was observed at other time point, regardless of conception. In sows that failed to conceive, the increase in IL-8 levels might have been cancelled or terminated before the first sampling time. These results highlight the importance of timely increases and subsequent declines in the levels of some cytokines for the establishment of pregnancy. Differences in uterine capacity start just after ovulation; detection and correction of these deviations can improve the reproductive efficiency of sows.

Immune Regulation of Seminal Plasma on the Endometrial Microenvironment: Physiological and Pathological Conditions

Seminal plasma (SP) accounts for more than 90% of semen volume. It induces inflammation, regulates immune tolerance, and facilitates embryonic development and implantation in the female reproductive tract. In the physiological state, SP promotes endometrial decidualization and causes changes in immune cells such as macrophages, natural killer cells, regulatory T cells, and dendritic cells. This leads to the secretion of cytokines and chemokines and also results in the alteration of miRNA profiles and the expression of genes related to endometrial tolerance and angiogenesis. Together, these changes modulate the endometrial immune microenvironment and contribute to implantation and pregnancy. However, in pathological situations, abnormal alterations in SP due to advanced age or poor diet in men can interfere with a woman's immune adaptation to pregnancy, negatively affecting embryo implantation and even the health of the offspring. Uterine pathologies such as endometriosis and endometritis can cause the endometrium to respond negatively to SP, which can further contribute to pathological progress and interfere with conception. The research on the mechanism of SP in the endometrium is conducive to the development of new targets for intervention to improve reproductive outcomes and may also provide new ideas for semen-assisted treatment of clinical infertility.

The effects of nutritional level and body condition score on cytokines in seminal plasma of beef bulls

Introduction

High quality semen is essential for reproductive efficiency. Nutrition and environmental factors impact the ejaculate components, like cytokines, that are essential for pregnancy establishment. We hypothesized that differing nutritional periods and body condition scores would affect seminal plasma cytokine concentrations of bulls.

Methods

Mature Angus bulls (n=11) were individually housed and randomly assigned to either over-fed (n=5) or restricted (n=6) treatment pathways. Bulls were fed different volumes of a single ration creating 8 individual treatment periods. Body weight and body condition scores were taken every 14 d to manage intake volumes. Ejaculates were collected every 84 d to determine seminal plasma cytokine profiles. A complete randomized design was used to evaluate seminal plasma cytokines after each nutritional treatment. Initial cytokine concentrations and volume of the ejaculate were included as covariates.

Results

All cytokines returned to initial concentrations following maintenance treatments at an ideal body condition score of 6. Nutritional treatments affected (P ≤ 0.05) IFN-γ, IL-8, MIP-1α, MIP-1β, TNF-α, IL-1β, and VEGF-A. However, TNF-α, IFN-γ, and MIP-1α had the greatest impact on cytokine profile.

Discussion

Nutritional levels and adiposity altered seminal plasma cytokine concentrations which could potentially impact the inflammatory balance of the uterus and the immune responses necessary for pregnancy establishment.

Starting to have sexual intercourse is associated with increases in cervicovaginal immune mediators in young women: a prospective study and meta-analysis

Background

Adolescent girls and young women (AGYW) are at high risk of sexually transmitted infections (STIs). It is unknown whether beginning to have sexual intercourse results in changes to immune mediators in the cervicovaginal tract that contribute to this risk.

Methods

We collected cervicovaginal lavages from Kenyan AGYW in the months before and after first penile-vaginal sexual intercourse and measured the concentrations of 20 immune mediators. We compared concentrations pre- and post-first sex using mixed effect models. We additionally performed a systematic review to identify similar studies and combined them with our results by meta-analysis of individual participant data.

Results

We included 180 samples from 95 AGYW, with 44% providing only pre-first sex samples, 35% matched pre and post, and 21% only post. We consistently detected 19/20 immune mediators, all of which increased post-first sex (p<0.05 for 13/19; Holm-Bonferroni-adjusted p<0.05 for IL-1β, IL-2, and CXCL8). Effects remained similar after excluding samples with STIs and high Nugent scores. Concentrations increased cumulatively over time after date of first sex, with an estimated doubling time of about 5 months.Our systematic review identified two eligible studies, one of 93 Belgian participants, and the other of 18 American participants. Nine immune mediators were measured in at least two-thirds of studies. Meta-analysis confirmed higher levels post-first sex for 8/9 immune mediators (p<0.05 for six mediators, most prominently IL-1α, IL-1β, and CXCL8).

Conclusions

Cervicovaginal immune mediator concentrations were higher in women who reported that they started sexual activity. Results were consistent across three studies conducted on three different continents.

Funding

This research was funded by R01 HD091996-01 (ACR), by P01 AI 030731-25 (Project 1) (AW), R01 AI116292 (FH), R03 AI154366 (FH) and by the Center for AIDS Research (CFAR) of the University of Washington/Fred Hutchinson Cancer Research Center AI027757.

Semen: A modulator of female genital tract inflammation and a vector for HIV-1 transmission

In order to establish productive infection in women, HIV must transverse the vaginal epithelium and gain access to local target cells. Genital inflammation contributes to the availability of HIV susceptible cells at the female genital mucosa and is associated with higher HIV transmission rates in women. Factors that contribute to genital inflammation may subsequently increase the risk of HIV infection in women. Semen is a highly immunomodulatory fluid containing several bioactive molecules with the potential to influence inflammation and immune activation at the female genital tract. In addition to its role as a vector for HIV transmission, semen induces profound mucosal changes to prime the female reproductive tract for conception. Still, most studies of mucosal immunity are conducted in the absence of semen or without considering its immune impact on the female genital tract. This review discusses the various mechanisms by which semen exposure may influence female genital inflammation and highlights the importance of routine screening for semen biomarkers in vaginal specimens to account for its impact on genital inflammation.

Antioxidants Present in Reproductive Tract Fluids and Their Relevance for Fertility

Nowadays, infertility is classified as a disease of the reproductive system. Although it does not compromise the life of the individual, it can have detrimental effects on the physiological and psychological health of the couple. Male fertility evaluation is mainly focused on the analysis of sperm parameters. However, the ejaculated fluid is also composed of seminal plasma, and the study of this fluid can provide crucial information to help in the assessment of male fertility status. Total antioxidant capacity of the seminal plasma has been positively correlated with the fertility of men. Moreover, evidence highlights to a similar importance as that of female reproductive tract fluid antioxidant capabilities and female fertility. Herein, we describe the functions of seminal plasma and female reproductive tract fluids, as well as their main antioxidant components and their relationships with fertility outcomes. Additionally, this review contains the most up to date information regarding the mechanisms of the interaction between the male and the female reproductive fluids and the importance of proper antioxidant capacity for fertilization.

Leukocytospermia induces intraepithelial recruitment of dendritic cells and increases SIV replication in colorectal tissue explants

Mucosal exposure to infected semen accounts for the majority of HIV-1 transmission events, with rectal intercourse being the route with the highest estimated risk of transmission. Yet, the impact of semen inflammation on colorectal HIV-1 transmission has never been addressed. Here we use cynomolgus macaques colorectal tissue explants to explore the effect of leukocytospermia, indicative of male genital tract inflammation, on SIVmac251 infection. We show that leukocytospermic seminal plasma (LSP) has significantly higher concentration of a number of pro-inflammatory molecules compared to normal seminal plasma (NSP). In virus-exposed explants, LSP enhance SIV infection more efficiently than NSP, being the increased viral replication linked to the level of inflammatory and immunomodulatory cytokines. Moreover, LSP induce leukocyte accumulation on the apical side of the colorectal lamina propria and the recruitment of a higher number of intraepithelial dendritic cells than with NSP. These results suggest that the outcome of mucosal HIV-1 infection is influenced by the inflammatory state of the semen donor, and provide further insights into mucosal SIV/HIV-1 pathogenesis.

What's Sex Got to Do With It? Understanding Potential Confounding and Exposure Misclassification in Mechanistic Sexually Transmitted Infection Research

We conducted a prospective study of 13 heterosexual couples to understand the impact of recent condomless vaginal sex on vaginal immune marker measurement and potential exposure misclassification due to the presence of semen. All immune markers were detectable in semen and concentrations of vaginal immune markers varied by sex recency.

Conditioned medium derived from seminal extracellular vesicles-exposed endometrial stromal cells induces inflammatory cytokine secretion by macrophages

OBJECTIVE

Seminal plasma (SP) contains large numbers of sub-cellular structures called extracellular vesicles (EV) which have been postulated to have immunological functions due to their bioactive contents including proteins and small non-coding RNAs. Although the response of endometrial cells to seminal EV (SEV) is recently being elucidated, the impact of these signaling vesicles on stroma-immune crosstalk is still unknown. Herein, we aimed to investigate the effect of conditioned medium (CM) derived from SEV-exposed endometrial stromal cells (eSC) on cytokine secretion by macrophages.

STUDY DESIGN

SEV were isolated from SP samples of healthy donors and characterized by common methods needed for EV characterization, including size determination by dynamic light scattering (DLS), transmission electron microscopy (TEM), and western blot analysis of EV markers. Endometrial biopsies were obtained from healthy individuals and eSC were isolated and characterized. EV internalization assay was performed by labeling the SEV with PKH67 green fluorescent dye. Then, the eSC were exposed to SEV and the CM was collected. Finally, the CM from SEV-exposed eSC was added to the macrophage culture and the level of inflammatory (interleukin (IL)-1α and IL-6) and anti-inflammatory (IL-10) cytokines were measured in the culture supernatant of macrophages.

RESULTS

The results demonstrated that the CM derived from SEV-exposed eSC induce IL-1α and IL-6 secretion by the macrophages, while the secretion of IL-10 was reduced.

CONCLUSION

Our results support the idea that the stroma-immune interaction is affected by SEV. This effect may be a part of immunoregulatory function of SP inside upper female genital tract and have an obvious impact during peri-implantation period.

The Impact of Semen Exposure on the Immune and Microbial Environments of the Female Genital Tract

Background: Semen induces an immune response at the female genital tract (FGT) to promote conception. It is also the primary vector for HIV transmission to women during condomless sex. Since genital inflammation and immune activation increase HIV susceptibility in women, semen-induced alterations at the FGT may have implications for HIV risk. Here we investigated the impact of semen exposure, as measured by self-reported condom use and Y-chromosome DNA (YcDNA) detection, on biomarkers of female genital inflammation associated with HIV acquisition. Methods: Stored genital specimens were collected biannually (mean 5 visits) from 153 HIV-negative women participating in the CAPRISA 008 tenofovir gel open-label extension trial. YcDNA was detected in cervicovaginal lavage (CVL) pellets by RT-PCR and served as a biomarker of semen exposure within 15 days of genital sampling. Protein concentrations were measured in CVL supernatants by multiplexed ELISA, and the frequency of activated CD4+CCR5+ HIV targets was assessed on cytobrush-derived specimens by flow cytometry. Common sexually transmitted infections (STIs) and bacterial vaginosis (BV)-associated bacteria were measured by PCR. Multivariable linear mixed models were used to assess the relationship between YcDNA detection and biomarkers of inflammation over time. Results: YcDNA was detected at least once in 69% (106/153) of women during the trial (median 2, range 1-5 visits), and was associated with marital status, cohabitation, the frequency of vaginal sex, and Nugent Score. YcDNA detection but not self-reported condom use was associated with elevated concentrations of several cytokines: IL-12p70, IL-10, IFN-γ, IL-13, IP-10, MIG, IL-7, PDGF-BB, SCF, VEGF, β-NGF, and biomarkers of epithelial barrier integrity: MMP-2 and TIMP-4; and with reduced concentrations of IL-18 and MIF. YcDNA detection was not associated with alterations in immune cell frequencies but was related to increased detection of P. bivia (OR = 1.970; CI 1.309-2.965; P = 0.001) at the FGT. Conclusion: YcDNA detection but not self-reported condom use was associated with alterations in cervicovaginal cytokines, BV-associated bacteria, and matrix metalloproteinases, and may have implications for HIV susceptibility in women. This study highlights the discrepancies related to self-reported condom use and the need for routine screening for biomarkers of semen exposure in studies of mucosal immunity to HIV and other STIs.

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Inflammatory Cytokine Profiles of Semen Influence Cytokine Responses of Cervicovaginal Epithelial Cells

Genital inflammatory cytokine responses increase HIV risk. Since male partner semen is a complex mixture of immune-modulatory prostaglandins and cytokines, we hypothesized that exposure to semen may influence genital inflammation in women. Here, we investigated cytokine response kinetics of cervical cells following stimulation with seminal plasma from HIV-negative and HIV-positive men characterized as having low or high concentrations of inflammatory cytokines. Irrespective of the HIV status or semen cytokine profile, in vitro stimulation of cervical cells with seminal plasma resulted in significantly elevated concentrations of secreted IL-6, IL-8, TNF-β, MCP-1, GM-CSF, and VEGF within 8 h of stimulation, which tended to decline by 24 h, although this was only significant for TNF-β. Consistent with this, cervical cells responded to seminal plasma with increases in IL-8 and IL-1β mRNA expression of 10-fold. These findings suggest that the impact of semen on local female genital cytokines is likely transient. Although these findings suggest that the impact of semen on local female genital cytokines may not be sustained long-term, this heightened genital inflammation may have implications for HIV risk in women.

Seminal plasma and cryopreservation alter ram sperm surface carbohydrates and interactions with neutrophils

Spermatozoa deposited vaginally must navigate the physical, chemical and immune barriers of the cervix to reach the site of fertilisation. Characteristics that favour successful cervical transit remain largely unknown beyond the obvious factors of motility and viability. Epididymal and cryopreserved ram spermatozoa demonstrate poor cervical transit, for unknown reasons. We hypothesised that seminal plasma exposure and cryopreservation alter the surface sugars of these sperm populations and, consequently, their interaction with immune cells, both potential factors for successful cervical transit. The carbohydrate profiles of epididymal, ejaculated and frozen–thawed ram spermatozoa were assessed by flow cytometry and western blotting using lectins for galactose, sialic acid, N-acetylglucosamine and mannose. Seminal plasma exposure and cryopreservation caused significant changes to the relative amounts of surface sugars detected by flow cytometry and lectin blotting. Immune cell interaction was characterised using a neutrophil-binding assay. Seminal plasma acted as a robust protective mechanism, limiting binding of spermatozoa, whereas the media used for cryopreservation caused a significant disruption to opsonin-mediated binding. We were unable to demonstrate a link between changes to surface sugars and neutrophil susceptibility. Seminal plasma and cryopreservation clearly alter the sperm glycocalyx, as well as the interaction of spermatozoa with immune cells.

A Bayesian view of murine seminal cytokine networks

It has long been established that active agents in seminal fluid are key to initiating and coordinating mating-induced immunomodulation. This is in part governed by the actions of a network of cytokine interactions which, to date, remain largely undefined, and whose interspecific evolutionary conservation is unknown. This study applied Bayesian methods to illustrate the interrelationships between seminal profiles of interleukin (IL)-1alpha, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12 (p70), IL-13, IL-17, eotaxin, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), interferon (IFN)-gamma, keratinocyte-derived chemokine (KC), monocyte chemoattractant protein (MCP-1), macrophage inflammatory protein (MIP-1) alpha, MIP-1beta, regulated on activation normal T cell expressed and secreted (RANTES), tumour necrosis factor (TNF)-alpha, leptin, inducible protein (IP)-10 and vascular endothelial growth factor (VEGF) in a rat model. IL-2, IL-9, IL-12 (p70), IL-13, IL-18, eotaxin, IFN-gamma, IP-10, KC, leptin, MCP-1, MIP-1alpha and TNF-alpha were significantly higher in serum, whilst IL-1beta, IL-5, IL-6, IL-10, IL-17, G-CSF and GM-CSF were significantly higher in seminal fluid. When compared to mouse profiles, only G-CSF was present at significantly higher levels in the seminal fluid in both species. Bayesian modelling highlighted key shared features across mouse and rat networks, namely TNF-alpha as the terminal node in both serum and seminal plasma, and MCP-1 as a central coordinator of seminal cytokine networks through the intermediary of KC and RANTES. These findings reveal a marked interspecific conservation of seminal cytokine networks.

Seminal plasma induces inflammation and enhances HIV-1 replication in human cervical tissue explants

The most immediate and evident effect of mucosal exposure to semen in vivo is a local release of proinflammatory mediators accompanied by an influx of leukocytes into the female genital mucosa (FGM). The implication of such response in HIV-1 transmission has never been addressed due to limitations of currently available experimental models. Using human tissue explants from the uterine cervix, we developed a system of mucosal exposure to seminal plasma (SP) that supports HIV-1 replication. Treatment of ectocervical explants with SP resulted in the upregulation of inflammatory and growth factors, including IL-6, TNF, CCL5, CCL20, CXCL1, and CXCL8, and IL1A, CSF2, IL7, PTGS2, as evaluated by measuring protein levels in explant conditioned medium (ECM) and gene expression in tissue. SP treatment was also associated with increased recruitment of monocytes and neutrophils, as observed upon incubation of peripheral blood leukocytes with ECM in a transwell system. To evaluate the impact of the SP-mediated response on local susceptibility to HIV-1, we infected ectocervical explants with the CCR5-tropic variant HIV-1BaL either in the presence of SP, or after explant pre-incubation with SP. In both experimental settings SP enhanced virus replication as evaluated by HIV-1 p24gag released in explant culture medium over time, as well as by HIV-1 DNA quantification in explants infected in the presence of SP. These results suggest that a sustained inflammatory response elicited by SP soon after coitus may promote HIV-1 transmission to the FGM. Nevertheless, ectocervical tissue explants did not support the replication of transmitted/founder HIV-1 molecular clones, regardless of SP treatment. Our system offers experimental and analytical advantages over traditional models of HIV-1 transmission for the study of SP immunoregulatory effect on the FGM, and may provide a useful platform to ultimately identify new determinants of HIV-1 infection at this site.

Immune Aspects of Female Infertility

Immune infertility, in terms of reproductive failure, has become a serious health issue involving approximately 1 out of 5 couples at reproductive age. Semen that is defined as a complex fluid containing sperm, cellular vesicles and other cells and components, could sensitize the female genital tract. The immune rejection of male semen in the female reproductive tract is explained as the failure of natural tolerance leading to local and/or systemic immune response. Present active immune mechanism may induce high levels of anti-seminal/sperm antibodies. It has already been proven that iso-immunization is associated with infertility. Comprehensive studies with regards to the identification of antibody-targets and the determination of specific antibody class contribute to the development of effective immuno-therapy and, on the other hand, potential immuno-contraception, and then of course to complex patient diagnosis. This review summarizes the aspects of female immune infertility.

Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress?

This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species (ROS). According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial ROS generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells.

The Impact of Sex Work Interruption on Blood-Derived T Cells in Sex Workers from Nairobi, Kenya

BACKGROUND

Unprotected sexual intercourse exposes the female genital tract (FGT) to semen-derived antigens, which leads to a proinflammatory response. Studies have shown that this postcoital inflammatory response can lead to recruitment of activated T cells to the FGT, thereby increasing risk of HIV infection.

OBJECTIVE

The purpose of this study was to evaluate the impact of sex work on activation and memory phenotypes of peripheral T cells among female sex workers (FSW) from Nairobi, Kenya.

SUBJECTS

Thirty FSW were recruited from the Pumwani Sex Workers Cohort, 10 in each of the following groups: HIV-exposed seronegative (at least 7 years in active sex work), HIV positive, and New Negative (HIV negative, less than 3 years in active sex work). Blood was obtained at three different phases (active sex work, abstinence from sex work-sex break, and following resumption of sex work). Peripheral blood mononuclear cells were isolated and stained for phenotypic markers (CD3, CD4, CD8, and CD161), memory phenotype markers (CD45RA and CCR7), activation markers (CD69, HLA-DR, and CD95), and the HIV coreceptor (CCR5). T-cell populations were compared between groups.

RESULTS

In HIV-positive women, CD8+CCR5+ T cells declined at the sex break period, while CD4+CD161+ T cells increased when returning to sex work. All groups showed no significant changes in systemic T-cell activation markers following the interruption of sex work, however, significant reductions in naive CD8+ T cells were noted. For each of the study points, HIV positives had higher effector memory and CD8+CD95+ T cells and lower naive CD8+ T cells than the HIV-uninfected groups.

CONCLUSIONS

Interruption of sex work had subtle effects on systemic T-cell memory phenotypes.

The ubiquitous hyaluronan: Functionally implicated in the oviduct?

Hyaluronan (hyaluronic acid) is a simple, nonantigenic, nonsulfated glycosaminoglycan present everywhere in the extracellular compartments of the body. Noteworthy, it is highly conserved phylogenetically, from sauropsida to mammals; and plays a plethora of roles from embryonic/fetal development to adult physiological and pathological events, including tumor development. In reproduction, hyaluronan has proven related to initial events as sperm survival, buildup of the sperm reservoir in the oviduct, regulation of sperm capacitation, and prefertilization to later participate in embryo, fetal, and placental development. Synthesis, binding (via the CD44 membrane receptor), and degradation of hyaluronan occur in male and female genital organs, the oviduct being no exception. This review discusses our current knowledge on roles of this ubiquitous glycosaminoglycan on the survival of immunologically foreign spermatozoa in the pig oviduct, a relevant event for fertility. During preovulatory storage in the functional tubal sperm reservoir, spermatozoa are entrapped in a mucus-like tubal fluid. This fluid contains fluctuating levels of hyaluronan, which is synthesized by the lining epithelium by hyaluronan synthase 3. Both hyaluronan and its CD44 receptor are particularly evident in the deep mucosal furrows of the sperm reservoir, in which most spermatozoa are embedded in; kept alive, uncapacitated but also undetected by the immune system of the female. Hyaluronan is also present in the seminal plasma, and evidence points toward an involvement of hyaluronan and its receptor in the local (tubal and possibly uterine) production of antiinflammatory cytokines, such as interleukin-10, pertaining maternal immune tolerance of these foreign cells.

The Paternal Contribution to Fetal Tolerance

Recognition of foreign paternal antigens expressed in the semi-allogeneic fetus by maternal immune cells is a requirement for successful pregnancy. However, despite intensive research activity during the last decades, the precise mechanisms contributing to the acceptance of the paternal alloantigens are still puzzling and pregnancy remains a fascinating phenomenon. Moreover, most studies focused on the maternal and fetal contribution to pregnancy success, and relatively little is known about the paternal involvement. In the current review, we address the contribution of paternal-derived factors to fetal-tolerance induction. First, we discuss data suggesting that in both humans and mice, the female body gets prepared for a pregnancy in every cycle, also in regard to male alloantigens delivered at coitus. Then, we provide an overview about factors present in seminal fluid and how these factors influence immune responses in the female reproductive tract. We further discuss ways of paternal alloantigen presentation and identify the immune modulatory properties of seminal fluid-derived factors with a special focus on Treg biology. Finally, we highlight the therapeutic potential of seminal fluid in different clinical applications.

Seminal Fluid Signalling in the Female Reproductive Tract: Implications for Reproductive Success and Offspring Health

Carriage of sperm is not the only function of seminal fluid in mammals. Studies in mice show that at conception, seminal fluid interacts with the female reproductive tract to induce responses which influence whether or not pregnancy will occur, and to set in train effects that help shape subsequent fetal development. In particular, seminal fluid initiates female immune adaptation processes required to tolerate male transplantation antigens present in seminal fluid and inherited by the conceptus. A tolerogenic immune environment to facilitate pregnancy depends on regulatory T cells (Treg cells), which recognise male antigens and function to suppress inflammation and immune rejection responses. The female response to seminal fluid stimulates the generation of Treg cells that protect the conceptus from inflammatory damage, to support implantation and placental development. Seminal fluid also elicits molecular and cellular changes in the oviduct and endometrium that directly promote embryo development and implantation competence. The plasma fraction of seminal fluid plays a key role in this process with soluble factors, including TGFB, prostaglandin-E, and TLR4 ligands, demonstrated to contribute to the peri-conception immune environment. Recent studies show that conception in the absence of seminal plasma in mice impairs embryo development and alters fetal development to impact the phenotype of offspring, with adverse effects on adult metabolic function particularly in males. This review summarises our current understanding of the molecular responses to seminal fluid and how this contributes to the establishment of pregnancy, generation of an immune-regulatory environment and programming long-term offspring health.

Development of HIV-1 rectal-specific microbicides and colonic tissue evaluation

The gastrointestinal tract is structurally and functionally different from the vagina. Thus, the paradigm of topical microbicide development and evaluation has evolved to include rectal microbicides (RMs). Our interest was to create unique RM formulations to safely and effectively deliver antiretroviral drugs to mucosal tissue. RMs were designed to include those that spread and coat all surfaces of the rectum and distal colon rapidly (liquid) and those that create a deformable, erodible barrier and remain localized at the administration site (gel). Tenofovir (TFV) (1%) was formulated as an aqueous thermoreversible fluid and a carbopol-based aqueous hydrogel. Lipid-based liquid and gel formulations were prepared for UC781 (0.1%) using isopropyl myristate and GTCC (Caprylic/Capric Triglycerides), respectively. Formulations were characterized for pH, viscosity, osmolality, and drug content. Pre-clinical testing incorporated ex vivo colonic tissue obtained through surgical resections and flexible sigmoidoscopy (flex sig). As this was the first time using tissue from both sources side-by-side, the ability to replicate HIV-1 was compared. Efficacy of the RM formulations was tested by applying the products with HIV-1 directly to polarized colonic tissue and following viral replication. Safety of the formulations was determined by MTT assay and histology. All products had a neutral pH and were isoosmolar. While HIV-1_BaL and HIV-1_JR-CSF alone and in the presence of semen had similar replication trends between surgically resected and flex sig tissues, the magnitude of viral replication was significantly better in flex sig tissues. Both TFV and UC781 formulations protected the colonic tissue, regardless of tissue source, from HIV-1 and retained tissue viability and architecture. Our in vitro and ex vivo results show successful formulation of unique RMs. Moreover, the results of flex sig and surgically resected tissues were comparable suggesting the incorporation of both in pre-clinical testing algorithms.

Semen lactoferrin promotes CCL20 production by epithelial cells: Involvement in HIV transmission

AIM: To study the effect of seminal plasma on Chemokine (C-C motif) ligand 20 (CCL20) production by epithelial cells and its relationship with lactoferrin.

METHODS: HEC-1A cells, a cell line derived from a monostratified endocervical epithelium, were incubated with samples of seminal plasma (diluted 1:10 in culture medium) recovered from human immunodeficiency virus (HIV) seronegative (HIV-) or HIV seropositive (HIV+) subjects. Recombinant human interleukin 1 beta (IL-1β) was used as positive control, and culture medium only as negative control. The measurement of CCL20 production in the supernatants of HEC-1A cells and of lactoferrin in seminal plasma was determined by enzyme-linked immunosorbent assay techniques. A fractionation of seminal plasma proteins was performed by ion exchange chromatography on a pool of seminal plasma specimens from HIV- subjects. Each fraction was tested for its ability to stimulate the production of CCL20 by HEC-1A cells and for its lactoferrin concentration. The HIV viral load in seminal plasma samples from HIV+ patients was measured using the HIV-Monitor kit (Roche Diagnostic Systems, Branchburg, NJ, United States).

RESULTS: The positive control IL-1β was responsible for an increase of 11.36 ± 3.36 times in the production of CCL20. Stimulation of HEC-1A cells was performed in 34 seminal plasma samples (22 from HIV+ subjects and 12 from HIV- subjects). The mean production of CCL20 by HEC-1A in presence of seminal plasma from HIV- and HIV+ subjects was respectively 5.38 ± 0.91 and 7.57 ± 3.26 times higher than that obtained with the untreated cells (P < 0.05 between the two groups). Using the same 34 specimens of seminal plasma, no correlation was observed between the concentration of total proteins in seminal plasma and their ability to stimulate the secretion of CCL20 by HEC-1 cells. In contrast, the ability to produce CCL20 by HEC-1A cells correlated to the concentration of lactoferrin in the seminal plasma samples (r coefficient = 0.56; CI: 0.26-0.76; P < 0.001). After fractionation by ion exchange chromatography, the seminal plasma fractions exhibiting the highest concentrations of lactoferrin were responsible for the greatest stimulation of CCL20 production by HEC-1A cells (r coefficient = 0.89; CI: 0.78-0.95; P < 0.0001).

CONCLUSION: Lactoferrin present in seminal plasma correlated with an increased production of CCL20 by HEC-1A cells and therefore could facilitate HIV entry through the genital mucosa.

Role of semen in altering the balance between inflammation and tolerance in the female genital tract: does it contribute to HIV risk?

While the main reproduction aim of semen is the transport of spermatozoa to the female genital tract, seminal plasma is a complex fluid that also carries a broad array of immunologically active molecules. Seminal plasma has been shown to contain a diverse array of anti-inflammatory and pro-inflammatory soluble mediators that regulate immune responses within the female reproductive tract than can facilitate fertilization. Since the natural inflammatory response to semen deposition in the female genital tract may result in recruitment of activated HIV target cells into the female genital mucosa, we discuss the constituents of semen that may increase the risk for HIV infection in women.

Association of sex work with reduced activation of the mucosal immune system

BACKGROUND

Unprotected intercourse and seminal discharge are powerful activators of the mucosal immune system and are important risk factors for transmission of human immunodeficiency virus (HIV). This study was designed to determine if female sex work is associated with changes in the mucosal immunity.

METHODS

Cervicovaginal lavage and plasma from 122 HIV-uninfected female sex workers (FSW) and 44 HIV-uninfected low-risk non-FSW from the same socioeconomic district of Nairobi were analyzed for evidence of immune activation (IA). The cervico-mononuclear cells (CMC) were analyzed for cellular activation by flow cytometry.

RESULTS

Lower IA was observed in FSW compared to the low-risk women as demonstrated by the lower level of MIP-3α (P < .001), ITAC (P < .001), MIG (p.0001), IL-1α (P < .001), IL-1β (P < .001), IL-1Rα (P = .0002), IL-6 (P < .001), IL-8 (P < .001), IL-10 (P = .01), IP-10 (P = .0001), MDC (P < .001), MIP-1α, (P < .001), MIP-1β (P = .005), MCP-1 (P = .03), and TNF-α (P = .006). Significant differences were noted as early as 1 year following initiation of sex work and increased with duration of sex work.

CONCLUSION

This study showed that sex work is associated with important changes in the mucosal immune system. By analyzing chemokine/cytokine levels and CMC activation, we observed a lower mucosal IA in HIV-uninfected FSW compared to low-risk women.

A role for the chemokine receptor CCR6 in mammalian sperm motility and chemotaxis

Although recent evidence indicates that several chemokines and defensins, well-known as inflammatory mediators, are expressed in the male and female reproductive tracts, the location and functional significance of chemokine networks in sperm physiology and sperm reproductive tract interactions are poorly understood. To address this deficiency in our knowledge, we examined the expression and function in sperm of CCR6, a receptor common to several chemoattractant peptides, and screened several reproductive tract fluids for the presence of specific ligands. CCR6 protein is present in mouse and human sperm and mainly localized in the sperm tail with other minor patterns in sperm from mice (neck and acrosomal region) and men (neck and midpiece regions). As expected from the protein immunoblotting and immunofluorescence results, mouse Ccr6 mRNA is expressed in the testis. Furthermore, the Defb29 mRNA encoding the CCR6 ligand, β-defensin DEFB29, is expressed at high levels in the epididymis. As determined by protein chip analysis, several chemokines (including some that act through CCR6, such as CCL20/MIP-3α (formerly macrophage inflammatory protein 3α) and protein hormones were present in human follicular fluid, endometrial secretions, and seminal plasma. In functional chemotaxis assays, capacitated human sperm exhibited a directional movement towards CCL20, and displayed modifications in motility parameters. Our data indicate that chemokine ligand/receptor interactions in the male and female genital tracts promote sperm motility and chemotaxis under non-inflammatory conditions. Therefore, some of the physiological reactions mediated by CCR6 ligands in male reproduction extend beyond a pro-inflammatory response and might find application in clinical reproduction and/or contraception.

Seminal fluid and the generation of regulatory T cells for embryo implantation

T regulatory (Treg) cells are essential mediators of the maternal immune adaptation necessary for embryo implantation. In mice, insufficient Treg cell activity results in implantation failure, or constrains placental function and fetal growth. In women, Treg cell deficiency is linked with unexplained infertility, miscarriage, and pre-eclampsia. To devise strategies to improve Treg cell function, it is essential to define the origin of the Treg cells in gestational tissues, and the regulators that control their functional competence and recruitment. Male seminal fluid is a potent source of the Treg cell-inducing agents TGFβ and prostaglandin E, and coitus is one key factor involved in expanding the pool of inducible Treg cells that react with paternal alloantigens shared by conceptus tissues. In mice, coitus initiates a sequence of events whereby female dendritic cells cross-present seminal fluid antigens and activate T cells, which in turn circulate via the blood to be sequestered into the endometrium. Similar events may occur in the human genital tract, where seminal fluid induces immune cell changes that appear competent to prime Treg cells. Improved understanding of how seminal fluid influences Treg cells in women should ultimately assist in the development of new therapies for immune-mediated pathologies of pregnancy.

Seminal plasma enhances cervical adenocarcinoma cell proliferation and tumour growth in vivo

Cervical cancer is one of the leading causes of cancer-related death in women in sub-Saharan Africa. Extensive evidence has shown that cervical cancer and its precursor lesions are caused by Human papillomavirus (HPV) infection. Although the vast majority of HPV infections are naturally resolved, failure to eradicate infected cells has been shown to promote viral persistence and tumorigenesis. Furthermore, following neoplastic transformation, exposure of cervical epithelial cells to inflammatory mediators either directly or via the systemic circulation may enhance progression of the disease. It is well recognised that seminal plasma contains an abundance of inflammatory mediators, which are identified as regulators of tumour growth. Here we investigated the role of seminal plasma in regulating neoplastic cervical epithelial cell growth and tumorigenesis. Using HeLa cervical adenocarcinoma cells, we found that seminal plasma (SP) induced the expression of the inflammatory enzymes, prostaglandin endoperoxide synthase (PTGS1 and PTGS2), cytokines interleukin (IL) -6, and -11 and vascular endothelial growth factor-A(VEGF-A). To investigate the role of SP on tumour cell growth in vivo, we xenografted HeLa cells subcutaneously into the dorsal flank of nude mice. Intra-peritoneal administration of SP rapidly and significantly enhanced the tumour growth rate and size of HeLa cell xenografts in nude mice. As observed in vitro, we found that SP induced expression of inflammatory PTGS enzymes, cytokines and VEGF-A in vivo. Furthermore we found that SP enhances blood vessel size in HeLa cell xenografts. Finally we show that SP-induced cytokine production, VEGF-A expression and cell proliferation are mediated via the induction of the inflammatory PTGS pathway.

Seminal fluid induces leukocyte recruitment and cytokine and chemokine mRNA expression in the human cervix after coitus

In mice, seminal fluid elicits an inflammation-like response in the female genital tract that activates immune adaptations to advance the likelihood of conception and pregnancy. In this study, we examined whether similar changes in leukocyte and cytokine parameters occur in the human cervix in response to the male partner's seminal fluid. After a period of abstinence in proven-fertile women, duplicate sets of biopsies were taken from the ectocervix in the periovulatory period and again 48 h later, 12 h after unprotected vaginal coitus, vaginal coitus with use of a condom, or no coitus. A substantial influx of CD45(+) cells mainly comprising CD14(+) macrophages and CD1a(+) dendritic cells expressing CD11a and MHC class II was evident in both the stratified epithelium and deeper stromal tissue after coitus. CD3(+)CD8(+)CD45RO(+) T cells were also abundant and increased after coitus. Leukocyte recruitment did not occur without coitus or with condom-protected coitus. An accompanying increase in CSF2, IL6, IL8, and IL1A expression was detected by quantitative RT-PCR, and microarray analysis showed genes linked with inflammation, immune response, and related pathways are induced by seminal fluid in cervical tissues. We conclude that seminal fluid introduced at intercourse elicits expression of proinflammatory cytokines and chemokines, and a robust recruitment of macrophages, dendritic cells, and memory T cells. The leukocyte and cytokine environment induced in the cervix by seminal fluid appears competent to initiate adaptations in the female immune response that promote fertility. This response is also relevant to transmission of sexually transmitted pathogens and potentially, susceptibility to cervical metaplasia.

Seminal plasma proteins: what role do they play?

PROBLEM

Semen is a heterogeneous and complex cell suspension in a protein-rich fluid with different functions, some of them well known, others still obscure.

METHOD OF STUDY

This paper reviews, comparatively, our current knowledge on the growing field of proteomics of the SP and its relevance in relation to the in vivo situation, for the sake of reproductive biology, diagnostics and treatment.

RESULTS

Ejaculated spermatozoa, primarily bathing in cauda epididymal fluid, are (in vitro) bulky, exposed to most, if not all, secretions from the accessory sexual glands. In vivo, however, not all spermatozoa are necessarily exposed to all secretions from these glands, because sperm cohorts are delivered in differential order and bathe in seminal plasma (SP) with different concentrations of constituents, including peptides and proteins. Proteins are relevant for sperm function and relate to sperm interactions with the various environments along the female genital tract towards the oocyte vestments. Specific peptides and proteins act as signals for the female immune system to modulate sperm rejection or tolerance, perhaps even influencing the relative intrinsic fertility of the male and/or couple by attaining a status of maternal tolerance towards embryo and placental development.

CONCLUSIONS

Proteins of the seminal plasma have an ample panorama of action, and some appear responsible for establishing fertility.

Prokineticin 1 induces inflammatory response in human myometrium: a potential role in initiating term and preterm parturition

The infiltration of human myometrium and cervix with leukocytes and the formation of a pro-inflammatory environment within the uterus have been associated with the initiation of both term and preterm parturition. The mechanism regulating the onset of this pro-inflammatory cascade is not fully elucidated. We demonstrate that prokineticin 1 (PROK1) is up-regulated in human myometrium and placenta during labor. The expression of PROK1 receptor remains unchanged during labor and is abundantly expressed in the myometrium. Gene array analysis identified 65 genes up-regulated by PROK1 in human myometrium, mainly cytokines and chemokines, including IL-1β, chemokine C-C motif ligand 3, and colony-stimulating factor 3. In addition, we demonstrate that PROK1 increases the expression of chemokine C-C motif ligand 20, IL-6, IL-8, prostaglandin synthase 2, and prostaglandin E(2) and F(2α) secretion. The treatment of myometrial explants with 100 ng/mL of lipopolysaccharide up-regulates the expression of PROK1, PROK1 receptor, and inflammatory mediators. The infection of myometrial explants with lentiviral microRNA targeting PROK1, preceding treatment with lipopolysaccharide, reduces the expression of inflammatory genes. We propose that PROK1 is a novel inflammatory mediator that can contribute to the onset of human parturition at term and partially mediate premature onset of inflammatory pathways during bacterial infection.

Coming of age: reconstruction of heterosexual HIV-1 transmission in human ex vivo organ culture systems

Heterosexual transmission of human immunodeficiency virus-1 (HIV-1), from men to women, involves exposure to infectious HIV-1 in semen. Therefore, the cellular and molecular processes that underlie HIV-1 transmission are closely interconnected with fundamental principles of human reproductive biology. Human ex vivo organ culture systems allow experimental reconstruction of HIV-1 transmission, using human semen and premenopausal cervicovaginal mucosal tissue, with specific emphasis on the progression from exposure to development of primary HIV-1 infection. Clearly, an isolated piece of human tissue cannot duplicate the full complexity of events in natural infections, but with correct observation of conventional medical and ethical standards, there is no opportunity to study HIV-1 exposure and primary infection in young women. Human mucosal organ cultures allow direct study of HIV-1 infection in a reproducible format while retaining major elements of complexity and variability that typify community-based HIV-1 transmission. Experimental manipulation of human mucosal tissue both allows and requires acquisition of new insights into basic processes of human mucosal immunology. Expanding from the current foundations, we believe that human organ cultures will become increasingly prominent in experimental studies of HIV-1 transmission and continuing efforts to prevent HIV-1 infection at human mucosal surfaces.

Effect of seminal plasma on uterine inflammation, contractility and pregnancy rates in mares

REASONS FOR PERFORMING STUDY

There is conflicting evidence over the role seminal plasma plays in sperm transport and inflammation within the uterus of mares. In in vitro studies, seminal plasma has been shown to reduce polymorphonuclear neutrophil (PMN) function, but the opposite effect on uterine inflammation has been reported in vivo.

OBJECTIVES

To study the effect of seminal plasma on uterine contractility, inflammation and pregnancy rates by inseminating mares with low doses of sperm free from seminal plasma (Group 1) and containing seminal plasma (Group 2).

METHODS

Synchronised mares were inseminated with 50 x 10(6) sperm in either skim milk extender or seminal plasma. Uterine lavage was performed 6 h after insemination to assess the inflammatory response. The contraction frequency of the uterus was measured over a 4 min period 10 mins and 6 h after insemination, using B-mode ultrasonography. Pregnancy rates were assessed 16 days after insemination.

RESULTS

Uterine contractions were less frequent in Group 1 mares inseminated with seminal plasma and significantly more PMNs were found in the lavage fluid of those mares. Pregnancy rates were identical in both groups (62%).

CONCLUSIONS

This study provides evidence that seminal plasma decreases uterine contractility and increases the inflammatory response of the uterus to semen. No effect of seminal plasma on pregnancy rates was demonstrated.

POTENTIAL RELEVANCE

Mares that develop persistent mating-induced endometritis may have inherently poor uterine contractility and impaired uterine clearance. The presence of seminal plasma during breeding may not be desirable in these mares. The role of seminal plasma in problem mares warrants additional study.

Sex-specific variation in the emphasis, inducibility and timing of the post-mating immune response in Drosophila melanogaster

Ecological immunology attempts to explain variation in immune function. Much of this work makes predictions about how potential hosts should invest in overall immunity. However, this 'overall' perspective under-emphasizes other critical aspects, such as the specificity, inducibility and timing of an immune response. Here, we investigate these aspects by examining gene regulation across several immune system components in both male and female Drosophila melanogaster prior to and after mating. To elucidate potentially important temporal dynamics, we also assayed several genes over time. We found that males and females emphasized different components of their immune system, however overall investment was similar. Specifically, the sexes emphasized different gene paralogues within major gene families, and males tended to invest more in gram-negative defence. By contrast, the inducibility of the immune response was both transient (lasting approx. 24 hours) and equal between the sexes. Furthermore, mating tended to induce humoral gene upregulation, while cell-mediated genes were unaffected. Within the humoral system, gram-negative bacterial defence genes exhibited a greater inducibility than those associated with fungal or gram-positive bacterial defence. Our results suggest that variation in the effectiveness of the immune response between the sexes may be driven by differences in emphasis rather than overall investment.

Evaluation of semen detection in vaginal secretions: comparison of four methods

PROBLEM

To determine the best method to detect semen in human vaginal secretions.

METHOD OF STUDY

Vaginal secretions from 302 pregnant women at mean 11.8 weeks' gestation were analyzed. Semen detection was assessed with: (i) measurement of total prostate-specific antigen (PSA), (ii) acid phosphatase activity, (iii) microscopic measurement of spermatozoa on Gram stain, and (iv) self-reported sexual intercourse in the past 2 days. Sensitivity and specificity were calculated for each technique in comparison with PSA levels.

RESULTS

A total of 119 (39.4%) women had a detectable PSA. Compared with measurable PSA, the sensitivity and specificity for other methods were: acid phosphatase (26.9%, 98.4%), Gram stain (36.1%, 98.4%), and self-report of intercourse in the past 48 hr (41.9%, 88.8%).

CONCLUSION

Compared with PSA levels, commonly used assays for recent semen exposure are inaccurate. This inaccuracy may affect the results of studies, which measure vaginal immune factors like cytokines or retrieve DNA from vaginal specimens.

Prokineticin 1 signaling and gene regulation in early human pregnancy

Prokineticin 1 (PROK1) is a recently described protein with a wide range of functions including tissue-specific angiogenesis, modulation of inflammatory responses, and regulation of hematopoiesis. The objective of this study was to investigate the role of PROK1 and prokineticin receptor 1 (PROKR1) in human endometrium during early pregnancy. PROK1 and PROKR1 expression is significantly elevated in first-trimester decidua, compared with nonpregnant endometrium. Expression of PROK1 and PROKR1 was localized in glandular epithelial and various cellular compartments within the stroma. To investigate the signaling pathways and target genes activated by PROK1, we generated an endometrial epithelial cell line stably expressing PROKR1 (Ishikawa PROKR1 cells). PROK1-PROKR1 interaction induced inositol phosphate mobilization and sequential phosphorylation of c-Src, epidermal growth factor receptor, and ERK 1/2. Gene microarray analysis on RNA extracted from Ishikawa PROKR1 cells treated with 40 nm PROK1 for 8 h revealed 49 genes to be differentially regulated. A number of these genes, including cyclooxygenase (COX)-2, leukemia inhibitory factor, IL-6, IL-8, and IL-11 are regulated in the endometrium during implantation and early pregnancy. We subsequently investigated the effect of PROK1 on expression of COX-2 in Ishikawa PROKR1 cells and first-trimester decidua. COX-2 mRNA and protein expression, and prostaglandin synthesis, were elevated in response to treatment with PROK1. Moreover, expression of COX-2 by PROK1 was dependent on activation of the Gq-phospholipase C-beta-cSrc-epidermal growth factor receptor-MAPK/ERK kinase pathway. These data demonstrate that PROK1 and PROKR1 expression is elevated in human decidua during early pregnancy and that PROK1-PROKR1 interaction regulates expression of a host of implantation-related genes.

Granulocyte-macrophage colony stimulating factor and interleukin-8 in the reproductive tract of ewes following oestrus and mating

Cytokines produced in the female reproductive tract after mating may enhance reproductive success. The present study investigated the distribution of granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin (IL)-8 in tissues and luminal secretions from different sites in the reproductive tract of the ewe following oestrus and after natural mating. Fifteen ewes were mated with a ram for 1 h and their reproductive tracts collected 3, 6, 18, 24 or 48 h later. Another 15 ewes were used as oestrous controls. Luminal secretions and tissue samples were collected from seven sites in each reproductive tract. Secretions were analysed by enzyme-linked immunosorbent assay and tissues were stained immunohistochemically using anti-sheep GM-CSF and anti-sheep IL-8 antibodies. Both cytokines were found in luminal and glandular endometrial epithelium and, to a lesser extent, in cervical epithelium; neither was found in the vaginal epithelium. Twice as many (P < 0.05) luminal samples from mated ewes than non-mated ewes were positive for GM-CSF. The vaginal lumen contained significantly higher (P < 0.01) concentrations of IL-8 compared with other sites, irrespective of mating status. Significant differences (P < 0.05) were found in staining intensity of GM-CSF and IL-8 from different sites. Production of GM-CSF and IL-8 by reproductive tissues is likely to contribute to leucocyte infiltration into the ovine reproductive tract.

Post-mating disparity between potential and realized immune response in Drosophila melanogaster

Reproductive costs are an essential component of evolutionary theory. For instance, an increase in reproduction is generally coupled with a decrease in immunocompetence shortly after mating. However, recent work in Drosophila melanogaster suggests that the potential to mount an immune response, as measured by the levels of immune gene expression, increases after mating. These data are in contrast to previous studies, which suggest that mating can reduce a fly's ability to survive an actual bacterial challenge (realized immunity). This pattern may be driven by some aspect of mating, independent of resource limitation, which reduces immune function by inhibiting the effective deployment of immune gene products. Though several studies have examined both the potential and the realized immunity after mating, none have examined these immune measures simultaneously. Here, we examined the link between the potential and the realized immunity in a sterile mutant of D. melanogaster. Shortly after mating, we found that female immune gene expression was high, but survival against infection was low. Surprisingly, this pattern was reversed within 24 h. Thus, estimates of immunity based on gene expression do not appear to reflect an actual ability to defend against pathogens in the hours following copulation. We discuss the possible mechanisms that may account for this pattern.

Immune parameters in mares resistant and susceptible to persistent post-breeding endometritis: Effects of immunomodulation

Our objective was to characterize immune parameters in susceptible (SM) and resistant (RM) mares, with and without artificial insemination (AI) and immunomodulation. Eight RM and eight SM were selected based on their reproductive history and functional tests. Both groups of mares were evaluated during three consecutive cycles: Cycle 1, untreated cycle (control); Cycle 2, AI with dead semen; Cycle 3, AI with dead semen and immunomodulation. Endometrial biopsies were taken during the three cycles as follows: Cycle 1--at estrus, when follicles > or =35mm and at diestrus (7+/-1 days after ovulation); Cycle 2--at estrus 24h post-AI, and at diestrus; Cycle 3--at estrus 24h after treatment with a Mycobacterium phlei cell-wall extract (MCWE) and AI, and at diestrus. The mRNA transcription (mRNAT) of IL-8 and IL-10 were determined by real-time PCR. Image analysis of immunohistochemistry slides was performed using digital software (Image-Pro Plus v 5.0; Media Cybernetics); the percentage of stained area was determined for Major Histocompatibility Complex II (MHC-II), polymorphonuclear leukocytes (PMN) and T lymphocytes (TL) on each tissue section. In Cycle 1, SM had significantly higher MHC-II, TL, PMN and IL-8 than RM during estrus (P<0.006, P<0.0005, P<0.05, respectively), while transcription of IL-10 was significantly lower than in RM (P<0.0001). During diestrus, SM had higher levels of TL, PMN and IL-8 than RM (P<0.0001). After AI (Cycle 2), SM had higher levels of IL-8 and lower levels of IL-10 than RM at estrus and no differences were detected for MHC-II, TL and PMN positive cells. During diestrus in the same cycle, all the immune parameters were higher in SM mares (P<0.005, P<0.0004, P<0.0001, P<0.02, respectively). When MCWE was applied at the time of AI (Cycle 3), SM expressed significant higher levels of IL-10 24h after treatment (P<0.005), which were also higher than in the control Cycle 2 or after AI (Cycle 2). However, no significant differences were detected for MHC-II, lymphocytes-PMN or IL-8 between SM and RM during diestrus in Cycle 3. This study showed that SM had higher levels of all immune parameters except IL-10 than RM during Cycle 1. After AI (Cycle 2), the inflammatory condition persisted in SM but not RM mares until day 7 post-ovulation. Following treatment with MCWE at the time of AI (Cycle 3) uterine immunological changes in SM resulted in an endometrial immune environment similar to that found in normal RM.

Seminal plasma differentially regulates inflammatory cytokine gene expression in human cervical and vaginal epithelial cells

Exposure to semen elicits an inflammatory response in the female reproductive tract of rodents and other animals. The nature and regulation of any similar response in humans is poorly understood. This study investigated seminal plasma induction of inflammatory cytokine and chemokine gene regulation in human cervical and vaginal epithelial cells in vitro. Affymetrix microarray gene profiling revealed that inflammatory cytokine genes were prevalent among 317 known genes differentially expressed in immortalized ectocervical epithelial (Ect1) cells after incubation with pooled human seminal plasma. A dose- and time-dependent induction by seminal plasma of IL8, IL6, CSF2 and CCL2 mRNA expression in Ect1 cells was verified by quantitative RT-PCR. This was accompanied by increases in Ect1 secretion of immunoactive gene products IL-8, IL-6, GM-CSF and MCP-1. Similar cytokine responses were elicited in primary ectocervical epithelial cells. Endocervical epithelial (End1) and vaginal epithelial (Vk2) cells were less responsive to seminal fluid, with induction of IL-8 and MCP-1, but not GM-CSF or IL-6. In a panel of 10 seminal plasma samples, considerable variation in inflammatory cytokine-inducing activity was evident. These experiments show that seminal plasma can elicit expression of a range of inflammatory cytokines and chemokines in reproductive tract epithelia, and implicate the ectocervix as the primary site of responsiveness, with gene-specific differences in the kinetics and site-restrictedness of the response. Seminal factor regulation of inflammatory cytokines in the cervical epithelium is implicated in controlling the immune response to seminal antigens, and defence against infectious agents introduced at intercourse.

Comparative sequence analyses reveal rapid and divergent evolutionary changes of the WFDC locus in the primate lineage

The initial comparison of the human and chimpanzee genome sequences revealed 16 genomic regions with an unusually high density of rapidly evolving genes. One such region is the whey acidic protein (WAP) four-disulfide core domain locus (or WFDC locus), which contains 14 WFDC genes organized in two subloci on human chromosome 20q13. WAP protease inhibitors have roles in innate immunity and/or the regulation of a group of endogenous proteolytic enzymes called kallikreins. In human, the centromeric WFDC sublocus also contains the rapidly evolving seminal genes, semenogelin 1 and 2 (SEMG1 and SEMG2). The rate of SEMG2 evolution in primates has been proposed to correlate with female promiscuity and semen coagulation, perhaps related to post-copulatory sperm competition. We mapped and sequenced the centromeric WFDC sublocus in 12 primate species that collectively represent four different mating systems. Our analyses reveal a 130-kb region with a notably complex evolutionary history that has included nested duplications, deletions, and significant interspecies divergence of both coding and noncoding sequences; together, this has led to striking differences of this region among primates and between primates and rodents. Further, this region contains six closely linked genes (WFDC12, PI3, SEMG1, SEMG2, SLPI, and MATN4) that show strong patterns of adaptive selection, although an unambiguous correlation between gene mutation rates and mating systems could not be established.

Reciprocal cross talk between gonadotropin-releasing hormone (GnRH) and prostaglandin receptors regulates GnRH receptor expression and differential gonadotropin secretion

The asynchronous secretion of gonadotrope LH and FSH under the control of GnRH is crucial for ovarian cyclicity but the underlying mechanism is not fully resolved. Because prostaglandins (PG) are autocrine regulators in many tissues, we determined whether they have this role in gonadotropes. We first demonstrated that GnRH stimulates PG synthesis by induction of cyclooxygenase-2, via the protein kinase C/c-Src/phosphatidylinositol 3'-kinase/MAPK pathway in the LbetaT2 gonadotrope cell line. We then demonstrated that PGF(2alpha) and PGI2, but not PGE2 inhibited GnRH receptor expression by inhibition of phosphoinositide turnover. PGF(2alpha), but not PGI2 or PGE2, reduced GnRH-induction of LHbeta gene expression, but not the alpha-gonadotropin subunit or the FSHbeta subunit genes. The prostanoid receptors EP1, EP2, FP, and IP were expressed in rat gonadotropes. Incubations of rat pituitaries with PGF(2alpha), but not PGI2 or PGE2, inhibited GnRH-induced LH secretion, whereas the cyclooxygenase inhibitor, indomethacin, stimulated GnRH-induced LH secretion. None of these treatments had any effect on GnRH-induced FSH secretion. The findings have thus elaborated a novel GnRH signaling pathway mediated by PGF(2alpha)-FP and PGI2-IP, which acts through an autocrine/paracrine modality to limit autoregulation of the GnRH receptor and differentially inhibit LH and FSH release. These findings provide a mechanism for asynchronous LH and FSH secretions and suggest the use of combination therapies of GnRH and prostanoid analogs to treat infertility, diseases with unbalanced LH and FSH secretion and in hormone-dependent diseases such as prostatic cancer.

Interleukin-10 promoter polymorphisms in male and female fertility and fecundity

Interleukin-10 (IL10) is assumed beneficial for a successful pregnancy; it may increase fertility and fecundity. Allele frequencies of IL10 polymorphisms at position -2849, -1082 and -592 were analyzed in association with a past history of fertility and fecundity in men and women of at least 85 years old. Fertility was decreased in association with the -2849 A allele in females; 27% of the AA genotype carriers produced no offspring in marriage compared to 14% of the G allele carriers (odds ratio (OR): 2.2, 95% confidence interval (CI): 1.2-4.2, P=0.01). Effective fecundability was decreased in association with the -2849 A allele in females; 7% of female -2849 AA genotype carriers had a child within 371 days of marriage (therefore, conceived within 3 months of marriage) compared to 28% of female G allele carriers (OR: 0.2, 95% CI: 0.04-0.7, P=0.01). This suggests an association between the -2849 AA genotype and a decreased fertility and fecundity in females.

Seminal plasma promotes the attraction of Langerhans cells via the secretion of CCL20 by vaginal epithelial cells: involvement in the sexual transmission of HIV

BACKGROUND

Heterosexual human immunodeficiency virus (HIV) transmission implies the crossing of the vaginal mucosa by virions present in the semen, potentially using Langerhans cells as transporters. The recruitment of these cells in the mucosa is mediated by the chemokine macrophage inflammatory protein 3alpha (CCL20). The aim of this study was to evaluate the capacity of the semen to induce Langerhans cell recruitment via the production of CCL20 by vaginal epithelial cells.

METHODS AND RESULTS

Using a vaginal epithelium model based on the SiHa cell line and human seminal plasma, we demonstrated that semen enhanced the production of CCL20. This secretion was regulated by the nuclear factor-kappaB intracellular signalling pathway. Fractionation of the seminal plasma indicated that the secretion of CCL20 was stimulated by high molecular weight compounds present in semen. Migration assays demonstrated that secreted CCL20 was able to promote the recruitment of Langerhans cell precursors (LCps), which remain permissive to X4 and R5 HIV infection.

CONCLUSIONS

Our results demonstrate that epithelial cells respond to factors present in semen by secreting CCL20, leading to the enhancement of LCp recruitment. These data argue in favour of the implication of epithelial cells in the heterosexual transmission of HIV.