T lymphocytes and macrophages, but not motile spermatozoa, are a significant source of human immunodeficiency virus in semen

Mucosal application of the broadly neutralizing antibody 10-1074 protects macaques from cell-associated SHIV vaginal exposure

Passive immunization using broadly neutralizing antibodies (bNAbs) is investigated in clinical settings to inhibit HIV-1 acquisition due to the lack of a preventive vaccine. However, bNAbs efficacy against highly infectious cell-associated virus transmission has been overlooked. HIV-1 transmission mediated by infected cells present in body fluids likely dominates infection and aids the virus in evading antibody-based immunity. Here, we show that the anti-N-glycans/V3 loop HIV-1 bNAb 10-1074 formulated for topical vaginal application in a microbicide gel provides significant protection against repeated cell-associated SHIV162P3 vaginal challenge in non-human primates. The treated group has a significantly lower infection rate than the control group, with 5 out of 6 animals fully protected from the acquisition of infection. The findings suggest that mucosal delivery of potent bnAbs may be a promising approach for preventing transmission mediated by infected cells and support the use of anti-HIV-antibody-based strategies as potential microbicides in human clinical trials.

Recommendations for reducing the risk of viral transmission during fertility treatment with the use of autologous gametes: a committee opinion

Sexually transmitted infections are of major concern to reproductive specialists. Heading the list are human immunodeficiency virus types 1 and 2 and hepatitis B and C viruses. These pathogens, which may cause incurable chronic infections, can be transmitted through assisted reproductive technologies and from infected mothers to the fetus or newborn. This document replaces the document of the same name, last published in 2020.

ESHRE guideline: medically assisted reproduction in patients with a viral infection/disease

STUDY QUESTION

What is the recommended management for medically assisted reproduction (MAR) in patients with a viral infection or disease, based on the best available evidence in the literature?

SUMMARY ANSWER

The ESHRE guideline on MAR in patients with a viral infection/disease makes 78 recommendations on prevention of horizontal and vertical transmission before, during and after MAR, and the impact on its outcomes, and these also include recommendations regarding laboratory safety on the processing and storage of gametes and embryos testing positive for viral infections.

WHAT IS KNOWN ALREADY

The development of new and improved anti-viral medications has resulted in improved life expectancy and quality of life for patients with viral infections/diseases. Patients of reproductive age are increasingly exploring their options for family creation.

STUDY DESIGN SIZE DURATION

The guideline was developed according to the structured methodology for the development of ESHRE guidelines. After the formulation of nine key questions for six viruses (hepatitis B virus, hepatitis C virus, human immunodeficiency virus, human papilloma virus, human T-lymphotropic virus I/II and Zika virus) by a group of experts, literature searches and assessments were performed. Papers published up to 2 November 2020 and written in English were included in the review. Evidence was analyzed by female, male or couple testing positive for the virus.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on the collected evidence, recommendations were formulated and discussed until consensus was reached within the guideline group. There were 61 key questions to be answered by the guideline development group (GDG), of which 12 were answered as narrative questions and 49 as PICO (Patient, Intervention, Comparison, Outcome) questions. A stakeholder review was organized after the finalization of the draft. The final version was approved by the GDG and the ESHRE Executive Committee.

MAIN RESULTS AND THE ROLE OF CHANCE

This guideline aims to help providers meet a growing demand for guidance on the management of patients with a viral infection/disease presenting in the fertility clinic.The guideline makes 78 recommendations on prevention of viral transmission before and during MAR, and interventions to reduce/avoid vertical transmission to the newborn. Preferred MAR treatments and interventions are described together with the effect of viral infections on outcomes. The GDG formulated 44 evidence-based recommendations-of which 37 were formulated as strong recommendations and 7 as weak-33 good practice points (GPP) and one research only recommendation. Of the evidence-based recommendations, none were supported by high-quality evidence, two by moderate-quality evidence, 15 by low-quality evidence and 27 by very low-quality evidence. To support future research in the field of MAR in patients with a viral infection/disease, a list of research recommendations is provided.

LIMITATIONS REASONS FOR CAUTION

Most interventions included are not well-studied in patients with a viral infection/disease. For a large proportion of interventions, evidence was very limited and of very low quality. More evidence is required for these interventions, especially in the field of human papilloma virus (HPV). Such future studies may require the current recommendations to be revised.

WIDER IMPLICATIONS OF THE FINDINGS

The guideline provides clinicians with clear advice on best practice in MAR for patients with a viral infection/disease, based on the best evidence currently available. In addition, a list of research recommendations is provided to stimulate further studies in the field.

STUDY FUNDING/COMPETING INTERESTS

The guideline was developed and funded by ESHRE, covering expenses associated with the guideline meetings, with the literature searches and with the dissemination of the guideline. The guideline group members did not receive any financial incentives, all work was provided voluntarily. A.D. reports research fees from Ferring and Merck, consulting fees from Ferring, outside the submitted work. C.P. reports speakers fees from Merck and MSD outside the submitted work. K.T. reports speakers fees from Cooper Surgical and Ferring and consultancy fees as member of the advisory board BioTeam of Ferring, outside the submitted work. The other authors have no conflicts of interest to declare.

DISCLAIMER

This guideline represents the views of ESHRE, which were achieved after careful consideration of the scientific evidence available at the time of preparation. In the absence of scientific evidence on certain aspects, a consensus between the relevant ESHRE stakeholders has been obtained. Adherence to these clinical practice guidelines does not guarantee a successful or specific outcome, nor does it establish a standard of care. Clinical practice guidelines do not replace the need for application of clinical judgment to each individual presentation, nor variations based on locality and facility type. ESHRE makes no warranty, express or implied, regarding the clinical practice guidelines and specifically excludes any warranties of merchantability and fitness for a particular use or purpose. (Full disclaimer available at  www.eshre.eu/guidelines.).

The Impact of SARS-CoV-2 on Sperm Cryostorage, Theoretical or Real Risk?

Cryopreservation of human gametes and embryos as well as human reproductive tissues has been characterized as an essential process and aspect of assisted reproductive technology (ART). Notably, sperm cryopreservation is a fundamental aspect of cryopreservation in oncological patients or patients undergoing gonadotoxic treatment. Given that there is a risk of contamination or cross-contamination, either theoretical or real, during the procedures of cryopreservation and cryostorage, both the European Society for Human Reproduction and Embryology (ESHRE) and the American Society for Reproductive Medicine (ASRM) have provided updated guidelines for preventing or reducing the contamination risk of sexually transmitted viruses. Given the ongoing and worldwide COVID-19 pandemic, there is considerable interest in what measures should be taken to mitigate SARS-CoV-2 contamination during cryopreservation and cryostorage of semen samples. The SARS-CoV-2 virus is the virus that causes COVID-19, and whose transmission and infection is mainly aerosol-mediated. Several ART professional societies, including ESHRE and ASRM have proposed measures to mitigate the spread of the SARS-CoV-2 virus. Whether the proposed safety directives are enough to mitigate the possible SARS-CoV-2-contamination of sperm samples during cryopreservation or whether the policies should be re-evaluated will be discussed in this review. Additionally, insights regarding the possible impact of COVID-19 vaccination on the safety of sperm cryopreservation will be discussed.

Recommendations for reducing the risk of viral transmission during fertility treatment with the use of autologous gametes: a committee opinion

Sexually transmitted infections are of major concern to reproductive specialists. Heading the list are human immunodeficiency virus types 1 and 2 and hepatitis B and C viruses. These pathogens, which may cause incurable chronic infections, can be transmitted through assisted reproductive technologies and from infected mothers to the fetus or newborn. This document replaces the document of the same name last published in 2013 (Fertil Steril 2013;99:340-6).

Potential for Virus Endogenization in Humans through Testicular Germ Cell Infection: the Case of HIV

Viruses have colonized the germ line of our ancestors on several occasions during evolution, leading to the integration in the human genome of viral sequences from over 30 retroviral groups and a few nonretroviruses. Among the recently emerged viruses infecting humans, several target the testis (e.g., human immunodeficiency virus [HIV], Zika virus, and Ebola virus). Here, we aimed to investigate whether human testicular germ cells (TGCs) can support integration by HIV, a contemporary retrovirus that started to spread in the human population during the last century. We report that albeit alternative receptors enabled HIV-1 binding to TGCs, HIV virions failed to infect TGCs in vitro Nevertheless, exposure of TGCs to infected lymphocytes, naturally present in the testis from HIV+ men, led to HIV-1 entry, integration, and early protein expression. Similarly, cell-associated infection or bypassing viral entry led to HIV-1 integration in a spermatogonial cell line. Using DNAscope, HIV-1 and simian immunodeficiency virus (SIV) DNA were detected within a few TGCs in the testis from one infected patient, one rhesus macaque, and one African green monkey in vivo Molecular landscape analysis revealed that early TGCs were enriched in HIV early cofactors up to integration and had overall low antiviral defenses compared with testicular macrophages and Sertoli cells. In conclusion, our study reveals that TGCs can support the entry and integration of HIV upon cell-associated infection. This could represent a way for this contemporary virus to integrate into our germ line and become endogenous in the future, as happened during human evolution for a number of viruses.IMPORTANCE Viruses have colonized the host germ line on many occasions during evolution to eventually become endogenous. Here, we aimed at investigating whether human testicular germ cells (TGCs) can support such viral invasion by studying HIV interactions with TGCs in vitro Our results indicate that isolated primary TGCs express alternative HIV-1 receptors, allowing virion binding but not entry. However, HIV-1 entered and integrated into TGCs upon cell-associated infection and produced low levels of viral proteins. In vivo, HIV-1 and SIV DNA was detected in a few TGCs. Molecular landscape analysis showed that TGCs have overall weak antiviral defenses. Altogether, our results indicate that human TGCs can support HIV-1 early replication, including integration, suggesting potential for endogenization in future generations.

Cryopreservation and IVF in the time of Covid-19: what is the best good tissue practice (GTP)?

Examine good tissue practices as relates to in vitro fertilization, biopsying, and vitrificationto compare current knowledge of ova, sperm, and embryos as vectors for disease transmission as it relates to our current knowledge regarding the SARS-CoV-2 virus.Unknown risks relating to the SARS-CoV-2 virus and sperm, ova, and embryos necessitate a reexamining of how human IVF is performed. Over the last decade, improvements in cryosurvival and live birth outcomes have been associated with zona pellucida breaching procedures (e.g., blastocyst collapsing and biopsying). In turn, today embryos are generally no longer protected by an intact zona pellucida when vitrified and in cryostorage. Additionally, high security storage containers have proven to be resilient to potential cross-contamination and reliable for routine human sperm freezing and embryo vitrification.Several options to current IVF practices are presented that can effectively mitigate the risks of cross-contamination and infection due to the current Covid-19 pandemic or other viral exposures. The question remains; is heightened security and change warranted where the risks of disease transmission likely remain negligible?

Vpr Is a VIP: HIV Vpr and Infected Macrophages Promote Viral Pathogenesis

HIV infects several cell types in the body, including CD4+ T cells and macrophages. Here we review the role of macrophages in HIV infection and describe complex interactions between viral proteins and host defenses in these cells. Macrophages exist in many forms throughout the body, where they play numerous roles in healthy and diseased states. They express pattern-recognition receptors (PRRs) that bind viral, bacterial, fungal, and parasitic pathogens, making them both a key player in innate immunity and a potential target of infection by pathogens, including HIV. Among these PRRs is mannose receptor, a macrophage-specific protein that binds oligosaccharides, restricts HIV replication, and is downregulated by the HIV accessory protein Vpr. Vpr significantly enhances infection in vivo, but the mechanism by which this occurs is controversial. It is well established that Vpr alters the expression of numerous host proteins by using its co-factor DCAF1, a component of the DCAF1-DDB1-CUL4 ubiquitin ligase complex. The host proteins targeted by Vpr and their role in viral replication are described in detail. We also discuss the structure and function of the viral protein Env, which is stabilized by Vpr in macrophages. Overall, this literature review provides an updated understanding of the contributions of macrophages and Vpr to HIV pathogenesis.

Viruses in the reproductive tract: On their way to the germ line?

Studies of vertebrate genomes have indicated that all species contain in their chromosomes stretches of DNA with sequence similarity to viral genomes. How such 'endogenous' viral elements (EVEs) ended up in host genomes is usually explained in general terms such as 'they entered the germ line at some point during evolution'. This seems a correct statement, but is also rather imprecise. The vast number of endogenous viral sequences suggest that common routes to the 'germ line' may exist, as relying on chance alone may not easily explain the abundance of EVEs in modern mammalian genomes. An increasing number of virus types have been detected in human semen and a growing number of studies have reported on viral infections that cause male infertility or subfertility and on viral infections that threaten in vitro fertilisation practices. Thus, it is timely to survey the pathway(s) that viruses can use to gain access to the human germ line. Embryo transfer and semen quality studies in livestock form another source of relevant information because virus infection during reproduction is clearly unwanted, as is the case for the human situation. In this review, studies on viruses in the male and female reproductive tract and in the early embryo will be discussed to propose a plausible viral route to the mammalian germ line.

The importance of semen leukocytes in HIV-1 transmission and the development of prevention strategies

HIV-1 sexual transmission occurs mostly through contaminated semen, which is a complex mixture of soluble factors with immunoregulatory functions and cells. It is well established that semen cells from HIV-1-infected men are able to produce the virus and that are harnessed to efficiently interact with mucosal barriers exposed during sexual intercourse. Several cofactors contribute to semen infectivity and may enhance the risk of HIV-1 transmission to a partner by increasing local HIV-1 replication in the male genital tract, thereby increasing the number of HIV-1-infected cells and the local HIV-1 shedding in semen. The introduction of combination antiretroviral therapy has improved the life expectancy of HIV-1 infected individuals; however, there is evidence that systemic viral suppression does not always reflect full viral suppression in the seminal compartment. This review focus on the role semen leukocytes play in HIV-1 transmission and discusses implications of the increased resistance of cell-mediated transmission to immune-based prevention strategies.

Broadly neutralizing antibodies potently inhibit cell-to-cell transmission of semen leukocyte-derived SHIV162P3

BACKGROUND

HIV-1 sexual transmission occurs mostly through infected semen, which contains both free virions and infected leukocytes. Transmission initiated by infected cells has been shown by several in vitro and in vivo studies and a reduced capacity of broadly neutralizing antibodies (bNAbs) to inhibit cell-to-cell transmission has also been reported. However, due to limitations of available experimental models, there is yet no clarity to which extend bNAbs can prevent transmission mediated by semen leukocytes.

METHODS

We developed a novel in vitro assay to measure cell-cell transmission that makes use of splenocytes or CD45+ semen leukocytes collected from acutely SHIV162P3-infected cynomolgus macaques. A panel of 11 bNAbs was used either alone or in combination to assess their inhibitory potential against both cell-free and cell-cell infection.

FINDINGS

Splenocytes and semen leucocytes displayed a similar proportion of CD4+T-cell subsets. Either cell type transferred infection in vitro to target TZM-bl cells and PBMCs. Moreover, infection of macaques was achieved following intravaginal challenge with splenocytes. The anti-N-glycans/V3 loop bNAb 10-1074 was highly efficient against cell-associated transmission mediated by infected spleen cells and its potency was maintained when transmission was mediated by CD45+ semen leukocytes.

INTERPRETATION

These results support the use of bNAbs in preventative or therapeutic studies aiming to block transmission events mediated not only by free viral particles but also by infected cells. Our experimental system could be used to predict in vivo efficacy of bNAbs.

FUNDING

This work was funded by the ANRS and the European Commission.

Innate and Adaptive Anti-SIV Responses in Macaque Semen: Implications for Infectivity and Risk of Transmission

HIV-1 infection is transmitted primarily by sexual exposure, with semen being the principal contaminated fluid. However, HIV-specific immune response in semen has been understudied. We investigated specific parameters of the innate, cellular, and humoral immune response that may affect semen infectivity in macaques infected with SIVmac251. Serial semen levels of cytokines and chemokines, SIV-specific antibodies, neutralization, and FcγR-mediated functions and SIV-specific T-cell responses were assessed and compared to systemic responses across 53 cynomolgus macaques. SIV infection induced an overall inflammatory state in the semen. Several pro-inflammatory molecules correlated with SIV virus levels. Effector CD8+ T cells were expanded in semen upon infection. SIV-specific CD8+ T-cells that expressed multiple effector molecules (IFN-γ+MIP-1β+TNF+/-) were induced in the semen of a subset of SIV-infected macaques, but this did not correlate with local viral control. SIV-specific IgG, commonly capable of engaging the FcγRIIIa receptor, was detected in most semen samples although this positively correlated with seminal viral load. Several inflammatory immune responses in semen develop in the context of higher levels of SIV seminal plasma viremia. These inflammatory immune responses could play a role in viral transmission and should be considered in the development of preventive and prophylactic vaccines.

Hyperviscous Semen Causes Poor Sperm Quality and Male Infertility through Induction of Oxidative Stress

Background/Aims

Semen hyperviscosity (SHV) is one of the significant factors involved in poor semen quality and male infertility. It also leads major problems during assisted reproduction techniques and in vitro fertilization process. Although influence of SHV on sperm quality, fertilization rate and male infertility have been widely considered, molecular and cellular mechanisms for these abnormalities are not well understood. In this review, we aimed to discuss the proposed cellular and molecular mechanisms of SHV on male reproductive system, the importance of oxidative stress (OS) and the mechanisms by which SHV induces OS and impairment of other antioxidants.

Methods

A PubMed/Medline and EM-BASE search was performed using keywords: "hyperviscosity semen", "oxidative stress", and "male infertility".

Conclusion

OS induced by reactive oxygen species can be considered as a major mechanism in patients with hyperviscosity semen that is associated with DNA fragmentation, lipid peroxidation and sperm membrane disintegrity, apoptosis, depletion of antioxidants, and subsequently poor sperm quality and male infertility. Therefore, antioxidant therapy may improve main pathological effects of hyperviscosity semen, especially oxidative damages and inflammation, on sperm quality and function. Further, randomized controlled studies are necessary to confirm these results and make a comparison between effects of various antioxidants such as N-acethyl-cysteine and Curcumin on fertility problem in patients with hyperviscous semen.

Improvement of Sperm Quality in Hyperviscous Semen following DNase I Treatment

Semen hyperviscosity impairs sperm motility and can lead to male infertility. This prospective study aimed at assessing the ability of exogenous DNase in improving sperm quality, taking into consideration that DNase has been found in the seminal plasma of several species and that neutrophils release chromatin in order to trap bacteria. A total of seventy-seven semen samples with high seminal viscosity (HSV) as the study group and sixty-two semen samples with normal seminal viscosity (NSV) as the control group were compared in this analysis. These semen samples were divided into three groups of receiving treatment (a) with DNase I at 37°C for 15 min, (b) by density gradient centrifugation, and (c) with a combination of the above two methods. Following a fifteen-minute treatment of hyperviscous semen, the motility of spermatozoa in 83% of semen samples increased to a statistically significant degree. On the contrary, DNase treatment of semen with normal viscosity had no such effects. The above treatment was also accompanied by a significant increase in the percentage of normal spermatozoa, resulting in a major decrease of the teratozoospermia index. Comparison between semen samples that underwent density gradient centrifugation following DNase I treatment, to those collected after density gradient treatment alone, showed that in the first case the results were more spectacular. The evaluation of each preparation in terms of yield (% total progressively motile sperm count after treatment in relation to the initial total sperm count) revealed that the combined approach resulted in 29.8% vs. 18.5% with density treatment alone (p=0.0121). DNase I treatment results in an improvement of sperm motility and morphology and could be beneficial to men with hyperviscous semen in assisted reproduction protocols.

HIV and SIV in Body Fluids: From Breast Milk to the Genitourinary Tract

HIV-1 is present in many secretions including oral, intestinal, genital, and breast milk. However, most people exposed to HIV-1 within these mucosal compartments do not become infected despite often frequent and repetitive exposure over prolonged periods of time. In this review, we discuss what is known about the levels of cell-free HIV RNA, cell-associated HIV DNA and cell-associated HIV RNA in external secretions. Levels of virus are usually lower than contemporaneously obtained blood, increased in settings of inflammation and infection, and decreased in response to antiretroviral therapy. Additionally, each mucosal compartment has unique innate and adaptive immune responses that affect the composition and presence of HIV-1 within each external secretion. We discuss the current state of knowledge about the types and amounts of virus present in the various excretions, touch on innate and adaptive immune responses as they affect viral levels, and highlight important areas for further study.

Monocytes but Not Lymphocytes Carrying HIV-1 on Their Surface Transmit Infection to Human Tissue Ex Vivo

Unprotected sexual intercourse with HIV-infected men is the major cause of new infections. HIV virions are released into semen by various cells of the male genital tract, as well as by infected monocytes and lymphocytes present in semen. Some of these virions may attach to the surfaces of cells, infected or uninfected. We investigated whether cells carrying attached HIV on their surfaces can transmit infection. We addressed this question in a model system of human tissue exposed ex vivo to monocytes and lymphocytes carrying HIV on their surfaces. We gamma irradiated the cells to prevent their productive infection. In spite of comparable amounts of HIV attached to monocytes and lymphocytes, only monocytes were capable of transmitting infection and triggering productive infection in tissue. This HIV-1 transmission was mediated by cell-cell contacts. Our experiments suggest that in vivo, HIV attached to infected or uninfected monocytes, which far outnumber lymphocytes in HIV-infected semen, may contribute to sexual transmission of HIV from men to their partners.

IMPORTANCE

The vast majority of new HIV infections occur through sexual transmission, in which HIV is transferred from the semen of an infected male to an uninfected partner. In semen, HIV-1 particles may exist as free-floating virions; inside infected cells; or attached to the surfaces of cells, whether they are infected or not. Here, we investigated whether HIV attached to the surfaces of monocytes or lymphocytes could transmit infection to human tissue. Incubation of human tissue with monocyte-attached HIV resulted in productive tissue infection. In contrast, there was no infection of tissues when they were incubated with lymphocyte-attached HIV-1. Our results highlight the important role that seminal monocytes may play in HIV transmission in vivo, especially since monocytes far outnumber lymphocytes in the semen of HIV-infected individuals.

Innate and Adaptive Mucosal Immunity in Protection against HIV Infection

The appalling toll on the populations of developing countries as a result of the HIV epidemic shows no signs of abatement. While costly drug therapies are effective in developed nations, the sheer scale of the epidemic elsewhere makes the need for a vaccine an ever more urgent goal. The prevalent DNA prime-viral boost strategy aims to elicit cytotoxic lymphocytes (CTL) against HIV, but this approach is undermined by the rapid mutation of HIV, which thereby escapes CTL control. Alloimmunity has been found to be protective in vertical transmission from infected mothers to their babies, in alloimmunization of women with their partners’ mononuclear cells, and in monkeys immunized with SIV grown in human T-cells. Vaginal mucosal immunization, as a result of unprotected sex with a regular partner, induced in vitro protection against HIV infection, and this was confirmed in macaques. The second type of natural protection is found in persons with the homozygous Δ32 CCR5 mutation, a 32-base-pair deletion of the CCR5 gene, which results in a lack of cell-surface expression of CCR5, which is associated with an increase in CC chemokines and the development of CCR5 antibodies. These two ‘experiments of nature’ have been used to develop vaccine strategies—first, in vaginal immunization of macaques with CCR5 peptides, in addition to HIV envelope (env) and SIV core (gag) antigens, all of which were linked to the 70-kD heat-shock protein (HSP70); and second, in mucosal allo-immunization of macaques, which also gave rise to in vitro protection from infection. Immunization with this vaccine elicited serum and vaginal IgG and IgA antibodies, IFNγ- and IL-12-producing cells, and increased concentrations of CCL-3 and CCL-4. Vaginal challenge with a simian immunodeficiency virus engineered to carry a human envelope protein (SHIV 89.6) showed significant clearance of SHIV in the immunized macaques. This platform strategy will now be developed to activate the co-stimulatory pathways with the aim of enhancing the primary allogeneic and CCR5-directed responses which are involved in natural protection against HIV infection. Abbreviations: IFN-γ, gamma interferon; IL-12, interleukin 12; MIP-1 α,β, Macrophage inflammatory protein-1; RANTES, Regulated on activation normal T-cell expressed and secreted; SDF-1, stromal-derived factor 1; SIV, simian immunodeficiency virus; and SHIV, engineered SIV carrying a human envelope protein.

Guidelines for risk reduction when handling gametes from infectious patients seeking assisted reproductive technologies

According to the Americans with Disabilities Act (1990), couples with blood-borne viruses that lead to infectious disease cannot be denied fertility treatment as long as the direct threat to the health and safety of others can be reduced or eliminated by a modification of policies or procedures. Three types of infectious patients are commonly discussed in the context of fertility treatment: those with human immunodeficiency virus (HIV), hepatitis C or hepatitis B. Seventy-five per cent of hepatitis C or HIV positive men and women are in their reproductive years, and these couples look to assisted reproductive techniques for risk reduction in conceiving a pregnancy. In many cases, only one partner is infected. Legal and ethical questions about treatment of infectious patients aside, the question most asked by clinical embryologists and andrologists is: "What are the laboratory protocols for working with gametes and embryos from patients with infectious disease?" The serostatus of each patient is the key that informs appropriate treatments. This guidance document describes protocols for handling gametes from seroconcordant and serodiscordant couples with infectious disease. With minor modifications, infectious patients with stable disease status and undetectable or low viral load can be accommodated in the IVF laboratory.

Cell-to-Cell Spread of HIV and Viral Pathogenesis

Human immunodeficiency virus type 1 (HIV-1) gives rise to a chronic infection that progressively depletes CD4(+) T lymphocytes. CD4(+) T lymphocytes play a central coordinating role in adaptive cellular and humoral immune responses, and to do so they migrate and interact within lymphoid compartments and at effector sites to mount immune responses. While cell-free virus serves as an excellent prognostic indicator for patient survival, interactions of infected T cells or virus-scavenging immune cells with uninfected T cells can greatly enhance viral spread. HIV can induce interactions between infected and uninfected T cells that are triggered by cell surface expression of viral Env, which serves as a cell adhesion molecule that interacts with CD4 on the target cell, before it acts as the viral membrane fusion protein. These interactions are called virological synapses and promote replication in the face of selective pressure of humoral immune responses and antiretroviral therapy. Other infection-enhancing cell-cell interactions occur between virus-concentrating antigen-presenting cells and recipient T cells, called infectious synapses. The exact roles that these cell-cell interactions play in each stage of infection, from viral acquisition, systemic dissemination, to chronic persistence are still being determined. Infection-promoting immune cell interactions are likely to contribute to viral persistence and enhance the ability of HIV-1 to evade adaptive immune responses.

Chlamydia trachomatis Infection of Endocervical Epithelial Cells Enhances Early HIV Transmission Events

Chlamydia trachomatis causes a predominantly asymptomatic, but generally inflammatory, genital infection that is associated with an increased risk for HIV acquisition. Endocervical epithelial cells provide the major niche for this obligate intracellular bacterium in women, and the endocervix is also a tissue in which HIV transmission can occur. The mechanism by which CT infection enhances HIV susceptibility at this site, however, is not well understood. Utilizing the A2EN immortalized endocervical epithelial cell line grown on cell culture inserts, we evaluated the direct role that CT-infected epithelial cells play in facilitating HIV transmission events. We determined that CT infection significantly enhanced the apical-to-basolateral migration of cell-associated, but not cell-free, HIVBaL, a CCR5-tropic strain of virus, across the endocervical epithelial barrier. We also established that basolateral supernatants from CT-infected A2EN cells significantly enhanced HIV replication in peripheral mononuclear cells and a CCR5+ T cell line. These results suggest that CT infection of endocervical epithelial cells could facilitate both HIV crossing the mucosal barrier and subsequent infection or replication in underlying target cells. Our studies provide a mechanism by which this common STI could potentially promote the establishment of founder virus populations and the maintenance of local HIV reservoirs in the endocervix. Development of an HIV/STI co-infection model also provides a tool to further explore the role of other sexually transmitted infections in enhancing HIV acquisition.

Caprine arthritis encephalitis: an example of risk assessment for embryo trading

The risk of transmission of caprine arthritis encephalitis virus (CAEV) during embryo transfer has been demonstrated in vivo through the detection of CAEV proviral DNA in: (1) flushing media for embryo collection; (2) cells of the cumulus oophorus surrounding the oocytes, ovarian follicle, oviduct and uterine tissues; and (3) testis, epididymis, vas deferens and vesicular glands. Experimentally infected embryos without a zona pellucida (ZP), washed 10 times with Minimum Essential Media (MEM) and 5% Fetal Calf Serum (FCS) solution, were capable of transmitting CAEV. In vitro we demonstrated that granulosa, oviductal, epididymal and embryo cells are fully susceptible to CAEV infection and allow active replication. However, AI with in vitro-infected semen can result in the production, after ten washing, of CAEV-free embryos, and ten washing in vitro- or in vivo-infected embryos with an intact ZP, or ten washing oocytes with an intact ZP, resulted in the production of virus-free female gametes or embryos that can be used for IVF or embryo transfer. Therefore, we have demonstrated that: (1) that CAEV-free embryos can be produced by IVF using spermatozoa infected in vitro by CAEV; and (2) embryo transfer can be used under field conditions to produce CAEV-free kids from CAEV-infected biological mothers.

Monoclonal and Single Domain Antibodies Targeting β-Integrin Subunits Block Sexual Transmission of HIV-1 in In Vitro and In Vivo Model Systems

BACKGROUND

Poor adherence to prevention regimens for gel-based anti-HIV-1 microbicides has been a major obstacle to more effective pre-exposure prophylaxis. Concern persists that the antiretroviral drug containing microbicides might promote development of antiretroviral resistance.

METHODS

Using in vitro transwell systems and a humanized mouse model of HIV-1 sexual transmission, we examined, as candidate microbicides, antibodies targeting the heterodimeric leukocyte function-associated antigen 1 (LFA-1), a non-virally encoded protein acquired by the virus that also plays a critical role cell movement across endothelial and epithelial barriers. LFA-1-specific single domain variable regions from alpaca heavy-chain only antibodies (VHH) were identified and evaluated for their ability to inhibit HIV-1 transmission in the in vitro transwell system.

RESULTS

Monoclonal antibodies targeting the CD11a and CD18 components of LFA-1 significantly reduced cell-free and cell-associated HIV-1 transmission in the in vitro transwell culture system and prevented virus transmission in the humanized mouse model of vaginal transmission. The broadly neutralizing monoclonal antibody b12 was unable to block transmission of cell-free virus. CD11a-specific VHH were isolated and expressed and the purified variable region protein domains reduced in vitro transepithelial transmission with an efficacy comparable with that of the CD11a monoclonal antibody.

CONCLUSIONS

Targeting integrins acquired by HIV-1 during budding and which are critical to interactions between epithelial cells and lymphocytes can reduce viral movement across epithelial barriers and prevent transmission in a humanized mouse model of sexual transmission. VHH capable of being produced by transformed bacteria can significantly reduce transepithelial virus transmission in in vitro model systems.

Critical Review: Immunomodulation by Seminal Factors and Implications for Male-to-Female HIV-1 Transmission

The role of semen in heterosexual transmission of the HIV-1 has been marginally viewed as an inert vehicle for the delivery of virus. However, studies from the field of reproductive biology have made it clear that seminal fluid is a complex and dynamic medium containing high concentrations of factors that play key roles in modulating the local immune response in the female reproductive tract during fertilization and embryogenesis. It is therefore strongly implied that the same seminal factors responsible for guiding the immune response in reproduction also play a role in male-to-female transmission of HIV-1. To begin to understand how these factors affect male-to-female HIV-1 transmission, multiple studies have comparatively profiled the contents of seminal fluid collected from uninfected and HIV-1-infected men. This review provides an overview of these studies, as well as a discussion of the potential impact of semen on HIV-1 transmission.

Nonhuman primate models for cell-associated simian immunodeficiency virus transmission: the need to better understand the complexity of HIV mucosal transmission

Nonhuman primates are extensively used to assess strategies to prevent infection from sexual exposure to human immunodeficiency virus (HIV) and to study mechanisms of mucosal transmission. However, although semen represents one of the most important vehicles for the virus, the vast majority of preclinical challenge studies have used cell-free simian immunodeficiency virus (SIV) or simian/human immunodeficiency virus (SHIV) viral particles inoculated as diluted culture supernatants. Semen is a complex body fluid containing many factors that may facilitate or decrease HIV infectiousness. The virus in semen is present in different forms: as free virus particles or as cell-associated virus (ie, within infected leukocytes). Although cell-to-cell transmission of HIV is highly efficient, the role of cell-associated virus in semen has been surprisingly poorly investigated in nonhuman primate models. Mucosal exposure of macaques to cell-associated SIV by using infected peripheral blood mononuclear cells or spleen cells has been shown to be an efficient means of infection; however, it has yet to be shown that SIV- or SHIV-infected seminal leukocytes can transmit infection in vivo. Improvement of animal models to better recapitulate the complex microenvironment at portals of HIV entry is needed for testing candidate antiretrovirals, microbicides, and vaccines.

Characteristics and quantities of HIV host cells in human genital tract secretions

Human immunodeficiency virus (HIV)-infected leukocytes have been detected in genital secretions from HIV-infected men and women and may play an important role in the sexual transmission of HIV. However, they have been largely overlooked in studies on mechanisms of HIV transmission and in the design and testing of HIV vaccine and microbicide candidates. This article describes the characteristics and quantities of leukocytes in male and female genital secretions under various conditions and also reviews evidence for the involvement of HIV-infected cells in both horizontal and vertical cell-associated HIV transmission. Additional research is needed in this area to better target HIV prevention strategies.

Modeling mucosal cell-associated HIV type 1 transmission in vitro

Human immunodeficiency virus type 1 (HIV-1) can efficiently spread by direct cell-to-cell contact, a mechanism termed cell-associated HIV transmission. By some estimates, cell-associated HIV transmission is 10-1000-fold more effective than cell-free HIV infection. Mucosal cell-associated HIV transmission may occur when HIV-bearing cells in mucosal secretions from an HIV-infected donor transfer virus directly to recipient target cells in or below the mucosal epithelium, or through HIV transcytosis across the mucosal epithelium of a noninfected host. This mechanism may play an important role in the sexual and vertical transmission of HIV-1, yet most in vitro tests of vaccine and microbicide efficacy assess cell-free virus transmission. This article reviews in vitro assays that have been used to model mucosal cell-associated transmission, including microscopy, immune cell cocultures, use of HIV-infected cells in epithelial cell transcytosis assays, and cell-associated infection of mucosal tissue explants. Assays that authentically simulate mucosal cell-associated HIV transmission could provide valuable insight into mechanisms and molecules that can potentially be targeted for HIV prevention, as well as critical models for testing novel HIV prevention strategies for efficacy against cell-associated HIV transmission.

Semen decontamination for the elimination of seminal HIV-1

The risk of human immunodeficiency virus (HIV) transmission to the female partner, or potential offspring of an HIV-1 infected man can be reduced using semen decontamination procedures before assisted reproductive treatment (ART). The objective of this study was to determine the efficiency of decontaminating semen samples (n = 186) from 95 HIV-1 sero-positive patients. Aliquots of neat semen were submitted for viral validation by qualitative and quantitative polymerase chain reaction. Semen samples were processed by density gradient centrifugation in combination with a ProInsert™ tube after which aliquots of the processed sperm samples were analysed for the presence of HIV-1. Fifty-four percent of all tested neat semen samples tested positive for HIV-1 DNA, RNA or both (13.4%, 11.3% and 29.0%, respectively). From a total of 103 processed sperm samples that were submitted for viral validation, two samples tested positive for HIV-1 DNA and none for RNA. In conclusion, semen processing with the ProInsert™ followed by viral validation of processed sperm samples should be carried out when providing ART to couples where the male partner is HIV-1 sero-positive.

Innate and adaptive immune responses in male and female reproductive tracts in homeostasis and following HIV infection

The male and female reproductive tracts are complex microenvironments that have diverse functional demands. The immune system in the reproductive tract has the demanding task of providing a protective environment for a fetal allograft while simultaneously conferring protection against potential pathogens. As such, it has evolved a unique set of adaptations, primarily under the influence of sex hormones, which make it distinct from other mucosal sites. Here, we discuss the various components of the immune system that are present in both the male and female reproductive tracts, including innate soluble factors and cells and humoral and cell-mediated adaptive immunity under homeostatic conditions. We review the evidence showing unique phenotypic and functional characteristics of immune cells and responses in the male and female reproductive tracts that exhibit compartmentalization from systemic immunity and discuss how these features are influenced by sex hormones. We also examine the interactions among the reproductive tract, sex hormones and immune responses following HIV-1 infection. An improved understanding of the unique characteristics of the male and female reproductive tracts will provide insights into improving clinical treatments of the immunological causes of infertility and the design of prophylactic interventions for the prevention of sexually transmitted infections.

Interactions between HIV-1 and mucosal cells in the female reproductive tract

Worldwide, the heterosexual route is the prevalent mode of HIV-1 transmission, and the female reproductive tract accounts for approximately 40% of all HIV-1 transmissions. HIV-1 infection in the female reproductive tract involves three major events: entry through the mucosal epithelium, productive infection in subepithelial mononuclear cells, and delivery to lymph nodes to initiate systemic infection. Here, we provide a focused review of the interaction between HIV-1 and mucosal epithelial cells, lymphocytes, macrophages, and dendritic cells in female genital mucosa. Increased understanding of these interactions could illuminate new approaches for interdicting HIV-1 heterosexual transmission.

Seminal fluid and reproduction: much more than previously thought

The influence of seminal plasma on the cytokine and immune uterine environment is well characterised in mice and humans, while the effects of disruption to uterine seminal plasma exposure on pregnancy and offspring health is becoming more clearly understood. The cellular and molecular environment of the uterus during the pre- and peri-implantation period of early pregnancy is critical for implantation success and optimal foetal and placental development. Perturbations to this environment not only have consequences for the success of pregnancy and neonatal health and viability, but can also drive adverse health outcomes in the offspring after birth, particularly the development of metabolic disorders such as obesity, hypertension and insulin resistance. It is now reported that an absence of seminal plasma at conception in mice promotes increased fat accumulation, altered metabolism and hypertension in offspring. The evidence reviewed here demonstrates that seminal plasma is not simply a transport medium for sperm, but acts also as a key regulator of the female tract environment providing optimal support for the developing embryo and benefiting future health of offspring.

HIV-1 vaginal transmission: cell-free or cell-associated virus?

The vast majority of new HIV infections in male-to-female transmission occurs through semen, where HIV-1 is present in two different forms: as free and as cell-associated virus. In the female lower genital tract, semen mixes with female genital secretions that contain various factors, some of which facilitate or inhibit HIV-1 transmission. Next, HIV-1 crosses the genital epithelia, reaches the regional lymph nodes, and disseminates through the female host. Cervico-vaginal mucosa contains multiple barriers, resulting in a low probability of vaginal transmission. However, in some cases, HIV-1 is able to break these barriers. Although the exact mechanisms of how these barriers function remain unclear, their levels of efficiency against cell-free and cell-associated HIV-1 are different, and both cell-free and cell-associated virions seem to use different strategies to overcome these barriers. Understanding the basic mechanisms of HIV-1 vaginal transmission is required for the development of new antiviral strategies to contain HIV-1 epidemics.

HY immune tolerance is common in women without male offspring

Background

Sex difference is an established risk factor for hematopoietic stem cell transplantation (HSCT)-related complications like graft versus host disease (GVHD). CD8^pos cytotoxic T cells specific for Y chromosome-encoded minor Histocompatibility antigens (HY) play an important role therein. Prior to HSC donation, female donors may encounter HY antigens through fetomaternal or transmaternal cell flow, potentially leading to the induction of HY-specific cytotoxic or regulatory immune responses. Whether HY priming occurs independent of parity, and whether HY priming is dependent on the presence of male microchimerism, is as yet unknown.

Methods

We investigated the presence of HY-specific regulatory T cells (Treg) and male microchimerism in 45 healthy women with a fully documented pregnancy and family history. HY peptide-induced linked suppression, a commonly reported functional feature of CD4^pos and CD8^pos Treg, was measured by trans vivo Delayed Type Hypersensitivity testing. As source of HY antigens, male microchimerism was analyzed by real-time PCR and defined by the presence of male DNA in at least one purified leukocyte cell type.

Results

HLA class I or class II restricted HY-specific Treg were detected in 26/42 (62%) women eligible for analysis. The prevalence of HY-specific Treg was significantly higher in women who had never given birth to sons than in women with male offspring (p = 0.004). Male microchimerism could be detected in 24 out of 45 (53%) women but did not correlate with the presence of HY specific Treg.

Conclusions

HY-specific Treg in women with male offspring have been described previously. Here we show for the first time that, in fact, HY specific Treg are more common in nulliparous women and in parous women with female offspring. Their presence is independent of the presence of male microchimerism. Whether HY-specific Treg presence in female stem cell grafts might decrease the GVHD incidence in male HSCT recipients needs to be investigated.

The oral mucosa immune environment and oral transmission of HIV/SIV

The global spread of human immunodeficiency virus (HIV) is dependent on the ability of this virus to efficiently cross from one host to the next by traversing a mucosal membrane. Unraveling how mucosal exposure of HIV results in systemic infection is critical for the development of effective therapeutic strategies. This review focuses on understanding the immune events associated with the oral route of transmission (via breastfeeding or sexual oral intercourse), which occurs across the oral and/or gastrointestinal mucosa. Studies in both humans and simian immunodeficiency virus (SIV) monkey models have identified viral changes and immune events associated with oral HIV/SIV exposure. This review covers our current knowledge of HIV oral transmission in both infants and adults, the use of SIV models in understanding early immune events, oral immune factors that modulate HIV/SIV susceptibility (including mucosal inflammation), and interventions that may impact oral HIV transmission rates. Understanding the factors that influence oral HIV transmission will provide the foundation for developing immune therapeutic and vaccine strategies that can protect both infants and adults from oral HIV transmission.

Semen CD4+ T cells and macrophages are productively infected at all stages of SIV infection in macaques

The mucosal events of HIV transmission have been extensively studied, but the role of infected cells present in the genital and rectal secretions, and in the semen, in particular, remains a matter of debate. As a prerequisite to a thorough in vivo investigation of the early transmission events through infected cells, we characterized in detail by multi-parameter flow cytometry the changes in macaque seminal leukocytes during SIVmac251 infection, focusing on T cells, macrophages and dendritic cells. Using immunocytofluorescence targeting SIV proteins and real-time quantitative PCR targeting SIV DNA, we investigated the nature of the infected cells on sorted semen leukocytes from macaques at different stages of infection. Finally, we cocultured semen CD4⁺ T cells and macrophages with a cell line permissive to SIV infection to assess their infectivity in vitro. We found that primary infection induced strong local inflammation, which was associated with an increase in the number of leukocytes in semen, both factors having the potential to favor cell-associated virus transmission. Semen CD4⁺ T cells and macrophages were productively infected at all stages of infection and were infectious in vitro. Lymphocytes had a mucosal phenotype and expressed activation (CD69 & HLA-DR) and migration (CCR5, CXCR4, LFA-1) markers. CD69 expression was increased in semen T cells by SIV infection, at all stages of infection. Macrophages predominated at all stages and expressed CD4, CCR5, MAC-1 and LFA-1. Altogether, we demonstrated that semen contains the two major SIV-target cells (CD4+ T cells and macrophages). Both cell types can be productively infected at all stages of SIV infection and are endowed with markers that may facilitate transmission of infection during sexual exposure.

Human Immunodeficiency Virus infection is predominantly transmitted by mucosal exposure, after sexual intercourse. Although substantial progresses have been recently achieved in our understanding of the mechanisms of HIV mucosal transmission, many questions remain. Semen is one of the major sources for HIV which contains both cell-free viral particles and viral infected cells. However, today, the role of cell-associated virus has been largely understudied. We provide here a detailed characterization of the semen leukocyte populations in the highly relevant experiment model of SIV infection of macaques. We demonstrate that the major target cells for the virus, CD4⁺ T cells and macrophages, are present in macaques semen at all stages of infection. Both cell types are productively infected in vivo and are endowed with adhesion and migration markers that may facilitate virus transmission during sexual exposure. The acute phase of infection is associated with a strong seminal inflammation that may increase semen leukocytes infectivity. This work supports for a role of cell-associated virus in HIV transmission which needs to be considered for the design of prevention strategies.

Transmission of chimeric HIV by mating in conventional mice: prevention by pre-exposure antiretroviral therapy and reduced susceptibility during estrus

Heterosexual transmission accounts for the majority of new human immunodeficiency virus (HIV) cases worldwide. The current approach to investigate HIV heterosexual transmission in animals involves application of virus stock to the vaginal surface, a method that does not reproduce the physiological conditions of vaginal intercourse that influence the rate of transmission. We have previously described efficient infection of conventional mice using EcoHIV/NL4-3 and EcoHIV/NDK, chimeric HIV molecular clones constructed to express all HIV structural and regulatory genes except envelope, which is replaced by a rodent-tropic envelope gene. Here we investigated whether EcoHIV/NDK-infected male mice transmit virus to females during coitus, and the sensitivity of this transmission to HIV pre-exposure prophylaxis and the estrus state. Our general approach was to allow mating between EcoHIV/NDK-infected male mice and uninfected females for 1–7 nights. At 1–6 weeks after mating, mice were euthanized and virus burdens were measured by quantitative PCR (qPCR) amplification of HIV RNA or DNA in peritoneal macrophages, inguinal lymph node cells, spleen cells or vas deferens, or by ELISA for antibodies to HIV Gag. We found that 70–100% of female mice mated to EcoHIV/NDK-infected males acquired infection. Pericoital treatment of females with either 2′,3′-dideoxcytidine (ddC) or tenofovir largely prevented their EcoHIV/NDK infection by mating (P<0.05 and P<0.003, respectively). In males, T cells were dispensable for virus transmission. The rate of EcoHIV/NDK sexual transmission to females in estrus declined sharply (P=0.003) but their infection by injection was unaffected, indicating that the local environment in the female reproductive tract influences susceptibility to HIV. We conclude that this system of EcoHIV/NDK transmission during mouse mating reproduces key features of heterosexual transmission of HIV in humans and can be used to investigate its biology and control.

Revising the Role of Myeloid cells in HIV Pathogenesis

Lentiviruses are characterized by their ability to infect resting cells, such as CD4 T cells, macrophages and dendritic cells (DC). Cells of myeloid lineage, which herein we include including monocytes, macrophages, and dendritic cells, play a pivotal role in HIV infection by not only promoting transmission and spread but also serving as viral reservoirs. However, the recent discovery of the HIV restriction factor SAMHD1 within myeloid cells has again led us to question the role of this lineage both in HIV transmission and pathogenesis. Herein we will summarize what the potential role of myeloid cells in HIV pathogenesis is and how recent observations have or haven't reshaped this view. Finally we highlight the idea that cells of myeloid lineage are quality rather than quantity HIV substrates. Thus, whilst is may indeed be difficult for a lentivirus like HIV to infect a resting cell like a macrophage and/or Dendritic cell, there are significant benefits in doing so, even at low frequency.

We are all born as microchimera

It is well accepted that pregnancy establishes microchimerism. Lately, transmaternal passage of cells from elder siblings has been suggested as possible source of non-fetal microchimerism in nulliparous women. Recently, we identified both non-maternal microchimerism and minor H antigen specific cellular immune responses against these microchimeric cells in umbilical cord blood. The identification of the latter microchimeric cells from birth onwards explains the high incidence of microchimerism in healthy people and in people with different diseases. The circulating microchimeric cells of different origin can induce a wealth of antigen specific responses. Thus, nobody is born naïve: we are all microchimera's.

Reproductive assistance in HIV serodiscordant couples

BACKGROUND

Three quarters of individuals infected with human immunodeficiency virus (HIV) are in their reproductive years and may consider pregnancy planning. Techniques have been developed which can minimize the risk of HIV transmission in these couples, and the current literature on this topic is reviewed here.

METHODS

We reviewed the literature for the following topics: risk of HIV transmission, effects of HIV infection on fertility, reproductive assistance in industrialized and low-income countries, pre-exposure chemoprophylaxis (PrEP) and timed intercourse in HIV-discordant couples for both male and female positivity. Relevant publications were identified through searches of the EMBASE Medline and PubMed databases, the Google-indexed scientific literature and periodic specialized magazines from the on-line Library Service of the University of Milan, Italy.

RESULTS

In serodiscordant couples in which the man is positive, the primary method used to prevent HIV transmission is 'sperm washing', followed by IUI or IVF. Data show that sperm washing in HIV-positive men has not produced seroconversion in women or their offspring; however, the evidence is limited. Recently, increasing evidence describing PrEP for HIV prevention has been published and PrEP could be an alternative to ART for fertile couples. Usually HIV-infected women undergo self-insemination around the time of ovulation. Few studies have been published on IVF outcome in HIV-infected women.

CONCLUSIONS

Assisted reproduction programmes should be integrated into global public health services against HIV. For HIV serodiscordant couples with infected men, sperm washing should be the first choice. However, timed intercourse and PrEP for HIV prevention has been reported. Recent data highlight the possible impairment of fertility in HIV-infected women. Efforts to design a multicentric study should be strengthened.

The Impact of Macrophage Nucleotide Pools on HIV-1 Reverse Transcription, Viral Replication, and the Development of Novel Antiviral Agents

Macrophages are ubiquitous and represent a significant viral reservoir for HIV-1. Macrophages are nondividing, terminally differentiated cells, which have a unique cellular microenvironment relative to actively dividing T lymphocytes, all of which can impact HIV-1 infection/replication, design of inhibitors targeting viral replication in these cells, emergence of mutations within the HIV-1 genome, and disease progression. Scarce dNTPs drive rNTP incorporation into the proviral DNA in macrophages but not lymphocytes. Furthermore, the efficacy of a ribose-based inhibitor that potently inhibits HIV-1 replication in macrophages, has prompted a reconsideration of the previously accepted dogma that 2′-deoxy-based inhibitors demonstrate effective inhibition of HIV-1 replication. Additionally, higher levels of dUTP and rNTP incorporation in macrophages, and lack of repair mechanisms relative to lymphocytes, provide a further mechanistic understanding required to develop targeted inhibition of viral replication in macrophages. Together, the concentrations of dNTPs and rNTPs within macrophages comprise a distinctive cellular environment that directly impacts HIV-1 replication in macrophages and provides unique insight into novel therapeutic mechanisms that could be exploited to eliminate virus from these cells.

Transmaternal cell flow leads to antigen-experienced cord blood

Umbilical cord blood (UCB) is used for HSCT. It is known that UCB can comprise Ag-specific T cells. Here we question whether solely transmaternal cell flow may immunize UCB. Twenty-three female UCB samples were collected from healthy mothers and analyzed for minor histocompatibility Ag HY-specific responses. Forty-two of 104 tetramer(pos) T-cell clones, isolated from 16 of 17 UCB samples, showed male-specific lysis in vitro. Male microchimerism was present in 6 of 12 UCB samples analyzed. In conclusion, female UCB comprises HY-specific cytotoxic T cells. The immunization is presumably caused by transmaternal cell flow of male microchimerism present in the mother. The presence of immune cells in UCB that are not directed against maternal foreign Ags is remarkable and may explain the reported clinical observation of improved HSCT outcome with younger sibling donors.

Outcomes of assisted reproductive techniques for HIV-1-discordant couples using thawed washed sperm in Taiwan: comparison with control and testicular sperm extraction/microscopic epididymal sperm aspiration groups

BACKGROUND/PURPOSE

An increasing number of human immunodeficiency virus-1 (HIV-l)-discordant couples in Taiwan have been seeking fertility help. We conducted the first clinical trial in Taiwan of assisted reproductive technology (ART) using sperm washing and viral load measurement.

METHODS

From 2005 to 2009, we performed 22 ART cycles on 14 HIV-1-discordant couples. The sperm washing involved density gradient centrifugation followed by swim-up method. HIV-1 RNA was checked by real-time reverse transcription-polymerase chain reaction with a sensitivity of 40 copies/mL. In addition, we enrolled two other groups of ART recipients using frozen sperm to compare the clinical outcomes.

RESULTS

There were five pregnancies in the fresh cycles (23.8%) of HIV-1-discordant couples and the cumulative pregnancy per couple was 42.9% (6/14). The data were comparable with normal controls and testicular sperm extraction/microscopic epididymal sperm aspiration groups. The nine babies and the 14 women in this study showed no seroconversion.

CONCLUSION

The preliminary data showed good ART results in HIV-1-discordant couples. Fertility services should not be withheld from individuals with HIV-1, although larger series are needed to reach conclusions about safety.

Isolation and characterization of T cells from semen

BACKGROUND

The male genital tract is of major importance in the transmission and acquisition of HIV-1. Studying cellular immunity in the male genital tract is important in development of HIV-1 vaccines protective at mucosal sites. Semen is the primary HIV-1 containing fluid released from the male genital tract and reducing virus levels in semen would also reduce HIV-1 spread. Characterizing lymphocytes from semen requires the isolation of viable T cells that can be analyzed by downstream applications such as flow cytometry. The aims of this study were to investigate the influence of various parameters on CD3(+) T cell yields from semen and to compare isolation methods to maximize CD3(+) T cell yields for the purpose of functional characterization by flow cytometry.

METHODS

The influence of abstinence, storage temperature and time till processing on semen CD3(+) T cell yields was investigated. Seminal CD3(+) T cell yields were evaluated by comparing gradient separation, enzymatic digestion, filtration and magnetic bead capture. The function and viability of seminal CD4(+) and CD8(+) T cells were assayed by flow cytometry.

RESULTS

We found that the use of pronase and cell strainers resulted in significantly higher CD3(+) T cell yields when compared to gradient separation alone. Positive selection of CD3(+) cells using magnetic bead purification resulted in significantly higher yields and improved resolution of lymphocyte subsets by flow cytometry. Processing of samples should occur as expediently as possible to maximize CD3(+) T cell yields. However, if this is not possible, loss of CD3(+) T cells can be minimized by storing samples at 37°C for up to one day post ejaculation.

CONCLUSIONS

We describe a simple method for the isolation of functional T cells from semen. Developing standardized methods for processing samples and measuring immunity in the male genital tract may be important in clinical trials of not only candidate HIV-1 vaccines, but in better understanding cellular immunity to a range of sexually transmitted infections of global significance.

Human immunodeficiency virus infects human seminal vesicles in vitro and in vivo

Semen represents the main vector of HIV dissemination worldwide, yet the origin of HIV in semen remains unclear. Viral populations distinct from those found in blood have been observed in semen, indicating local viral replication within the male genital tract. The seminal vesicles, the secretions of which constitute more than 60% of the seminal fluid, could represent a major source of virus in semen. This study is the first to investigate the susceptibility of human seminal vesicles to HIV infection both in vitro and in vivo. We developed and characterized an organotypic culture of human seminal vesicles to test for target cells and HIV infection, and, in parallel, analyzed the seminal vesicle tissues from HIV-infected donors. In vitro, in contrast to HIV-1 X4, HIV-1 R5 exposure induced productive infection. Infected cells consisted primarily of resident CD163(+) macrophages, often located close to the lumen. In vivo, HIV protein and RNA were also detected primarily in seminal vesicle macrophages in seven of nine HIV-infected donors, some of whom were receiving prolonged suppressive highly active antiretroviral therapy. These results demonstrate that human seminal vesicles support HIV infection in vitro and in vivo and, therefore, have the potential to contribute virus to semen. The presence of infected cells in the seminal vesicles of treated men with undetectable viremia suggests that this organ could constitute a reservoir for HIV.

Inhibition of the transport of HIV in vitro using a pH-responsive synthetic mucin-like polymer system

In conjunction with the routine role of delivering the active ingredient, carefully designed drug delivery vehicles can also provide ancillary functions that augment the overall efficacy of the system. Inspired by the ability of the cervicovaginal mucus to impede the movement of HIV virions at acidic pH, we have engineered a pH-responsive synthetic polymer that shows improved barrier properties over the naturally occurring cervicovaginal mucus by inhibiting viral transport at both acidic and neutral pH. The pH-responsive synthetic mucin-like polymer is constructed with phenylboronic acid (PBA) and salicylhydroxamic acid (SHA), each individually copolymerized with a 2-hydroxypropyl methacrylamide (pHPMA) polymer backbone. At pH 4.8, the crosslinked polymers form a transient network with a characteristic relaxation time of 0.9 s and elastic modulus of 11 Pa. On addition of semen, the polymers form a densely crosslinked elastic network with a characteristic relaxation time greater than 60 s and elastic modulus of 1800 Pa. Interactions between the PBA-SHA crosslinked polymers and mucin at acidic pH showed a significant increase in elastic modulus and crosslink lifetime (p < 0.05). A transport assay revealed that migration of HIV and cells was significantly impeded by the polymer network at pH ≥ 4.8 with a diffusion coefficient of 1.60 x 10(-4) μm(2)/s for HIV. Additionally, these crosslinked polymers did not induce symptoms of toxicity or irritation in either human vaginal explants or a mouse model. In summary, the pH-responsive crosslinked polymer system reported here holds promise as a class of microbicide delivery vehicle that could inhibit the transport of virions from semen to the target tissue and, thereby, contribute to the overall activity of the microbicide formulation.

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.

The role of semen in sexual transmission of HIV: beyond a carrier for virus particles

Unprotected sexual intercourse between discordant couples is by far the most frequent mode of HIV-1 (human immunodeficiency virus type 1) transmission being semen the main vector for HIV-1 dissemination worldwide. Semen is usually considered merely as a vehicle for HIV-1 transmission. In this review we discuss recent observations suggesting that beyond being a carrier for virus particles semen markedly influences the early events involved in sexual transmission of HIV through the mucosal barriers.