T-Cell Expression of Angiotensin-Converting Enzyme 2 and Binding of Severe Acute Respiratory Coronavirus 2.

The pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not completely understood. SARS-CoV-2 infection frequently causes significant immune function consequences including reduced T cell numbers and enhanced T cell exhaustion that contribute to disease severity. The extent to which T cell effects are directly mediated through infection or indirectly result from infection of respiratory-associated cells is unclear. We show that primary human T cells express sufficient levels of angiotensin converting enzyme 2 (ACE-2), the SARS-CoV-2 receptor, to mediate viral binding and entry into T cells. We further show that T cells exposed to SARS-CoV-2 particles demonstrate reduced proliferation and apoptosis compared to uninfected controls, indicating that direct interaction of SARS-CoV-2 with T cells may alter T cell growth, activation, and survival. Regulation of T cell activation and/or turnover by SARS-CoV-2 may contribute to impaired T cell function observed in patients with severe disease.

Urban Particulate Matter Impairment of Airway Surface Liquid-Mediated Coronavirus Inactivation.

Air pollution particulate matter (PM) is associated with SARS-CoV-2 infection and severity, although mechanistic studies are lacking. We tested whether airway surface liquid (ASL) from primary human airway epithelial cells is antiviral against SARS-CoV-2 and human alphacoronavirus 229E (CoV-229E) (responsible for common colds), and whether PM (urban, indoor air pollution [IAP], volcanic ash) affected ASL antiviral activity. ASL inactivated SARS-CoV-2 and CoV-229E. Independently, urban PM also decreased SARS-CoV-2 and CoV-229E infection, and IAP PM decreased CoV-229E infection. However, in combination, urban PM impaired ASL's antiviral activity against both viruses, and the same effect occurred for IAP PM and ash against SARS-CoV-2, suggesting that PM may enhance SARS-CoV-2 infection.

Proteomics Profiling of Autologous Blood and Semen Exosomes from HIV-infected and Uninfected Individuals Reveals Compositional and Functional Variabilities.

Blood and semen are important body-fluids that carry exosomes for bioinformation transmission. Therefore, characterization of their proteomes is necessary for understanding body-fluid-specific physiologic and pathophysiologic functions. Using systematic multifactorial proteomic profiling, we characterized the proteomes of exosomes and exosome-free fractions from autologous blood and semen from three HIV-uninfected and three HIV-infected participants (total of 24 samples). We identified exosome-based protein signatures specific to blood and semen along with HIV-induced tissue-dependent proteomic perturbations. We validated our findings with samples from 16 additional donors and showed that unlike blood exosomes (BE), semen exosomes (SE) are enriched in clusterin. SE but not BE promote Protein·Nucleic acid binding and increase cell adhesion irrespective of HIV infection. This is the first comparative study of the proteome of autologous BE and SE. The proteins identified may be developed as biomarkers applicable to different fields of medicine, including reproduction and infectious diseases.

Vehicles of intercellular communication: exosomes and HIV-1.

The terms extracellular vesicles, microvesicles, oncosomes, or exosomes are often used interchangeably as descriptors of particles that are released from cells and comprise a lipid membrane that encapsulates nucleic acids and proteins. Although these entities are defined based on a specific size range and/or mechanism of release, the terminology is often ambiguous. Nevertheless, these vesicles are increasingly recognized as important modulators of intercellular communication. The generic characterization of extracellular vesicles could also be used as a descriptor of enveloped viruses, highlighting the fact that extracellular vesicles and enveloped viruses are similar in both composition and function. Their high degree of similarity makes differentiating between vesicles and enveloped viruses in biological specimens particularly difficult. Because viral particles and extracellular vesicles are produced simultaneously in infected cells, it is necessary to separate these populations to understand their independent functions. We summarize current understanding of the similarities and differences of extracellular vesicles, which henceforth we will refer to as exosomes, and the enveloped retrovirus, HIV-1. Here, we focus on the presence of these particles in semen, as these are of particular importance during HIV-1 sexual transmission. While there is overlap in the terminology and physical qualities between HIV-1 virions and exosomes, these two types of intercellular vehicles may differ depending on the bio-fluid source. Recent data have demonstrated that exosomes from human semen serve as regulators of HIV-1 infection that may contribute to the remarkably low risk of infection per sexual exposure.

Semen Exosomes Promote Transcriptional Silencing of HIV-1 by Disrupting NF-κB/Sp1/Tat Circuitry.

Exosomes play various roles in host responses to cancer and infective agents, and semen exosomes (SE) inhibit HIV-1 infection and transmission, although the mechanism(s) by which this occurs is unclear. Here, we show that SE block HIV-1 proviral transcription at multiple transcriptional checkpoints, including transcription factor recruitment to the long terminal repeat (LTR), transcription initiation, and elongation. Biochemical and functional studies show that SE inhibit HIV-1 LTR-driven viral gene expression and virus replication. Through partitioning of the HIV-1 RNA, we found that SE reduced the optimal expression of various viral RNA species. Chromatin immunoprecipitation-real-time quantitative PCR (ChIP-RT-qPCR) and electrophoretic mobility shift assay (EMSA) analysis of infected cells identified the human transcription factors NF-κB and Sp1, as well as RNA polymerase (Pol) II and the viral protein transcriptional activator (Tat), as targets of SE. Of interest, SE inhibited HIV-1 LTR activation mediated by HIV-1 or Tat, but not by the mitogen phorbol myristate acetate (PMA) or tumor necrosis factor alpha (TNF-α). SE inhibited the DNA binding activities of NF-κB and Sp1 and blocked the recruitment of these transcription factors and Pol II to the HIV-1 LTR promoter. Importantly, SE directly blocked NF-κB, Sp1, and Pol II binding to the LTR and inhibited the interactions of Tat/NF-κB and Tat/Sp1, suggesting that SE-mediated inhibition of the functional quadripartite complex NF-κB-Sp1-Pol II-Tat may be a novel mechanism of proviral transcription repression. These data provide a novel molecular basis for SE-mediated inhibition of HIV-1 and identify Tat as a potential target of SE.IMPORTANCE HIV is most commonly transmitted sexually, and semen is the primary vector. Despite progress in studies of HIV pathogenesis and the success of combination antiretroviral therapy in controlling viral replication, current therapy cannot completely control sexual transmission. Thus, there is a need to identify effective methods of controlling HIV replication and transmission. Recently, it was shown that human semen contains exosomes that protect against HIV infection in vitro In this study, we identified a mechanism by which semen exosomes inhibited HIV-1 RNA expression. We found that semen exosomes inhibit recruitment of transcription factors NF-κB and Sp1, as well as RNA Pol II, to the promoter region in the 5' long terminal repeat (LTR) of HIV-1. The HIV-1 early protein transcriptional activator (Tat) was a target of semen exosomes, and semen exosomes inhibited the binding and recruitment of Tat to the HIV-1 LTR.

Coxiella burnetii seroprevalence in domestic goat does in the United States: Prevalence, distribution, and associated risk factors.

Infection with the bacterium Coxiella burnetii can cause coxiellosis in animals and Q fever in humans. Coxiellosis a consistently underreported infectious disease. The infection can result in reproductive consequences for humans and animals. Ruminants are a reservoir for infection and humans are generally infected via aerosolized secretions, making it a public health concern. Studies of ruminant seroprevalence are generally limited in size and scope. This study determined seroprevalence in a large-scale U.S. population of female goats using serum samples from 7736 does from 24 states. This study identified C. burnetii seroprevalence in the United States domestic goat population. Overall, 14.5 % (SE = 2.3) of does were seropositive and 21.0 % (SE = 2.4) of operations had at least 1 seropositive doe. Further, operation demographics and herd management practices associated with seropositivity were as follows: the suspected or confirmed presence of caprine arthritis encephalitis (CAE), caseous lymphadenitis (CL), Johne's disease, or sore mouth in the herd in the previous 3 years, not cleaning or disinfecting the kidding areas or removing aborting does from other does, allowing visitors to access the kidding areas, and a lower percentage of adult goat inventory that were adult bucks or wethers. Furthermore, goat breed was associated with seropositivity. These data show C. burnetii seroprevalence in the United States and identify operation and animal characteristics and management practices associated with C. burnetii seropositivity. Together, this information can be used to help limit animal transmission, inform public health measures, and help educate and protect individuals working with goats.

Inactivation of highly transmissible livestock and avian viruses including influenza A and Newcastle disease virus for molecular diagnostics.

There is a critical need for an inactivation method that completely inactivates pathogens at the time of sample collection while maintaining the nucleic acid quality required for diagnostic PCR testing. This inactivation method is required to alleviate concerns about transmission potential, minimize shipping complications and cost, and enable testing in lower containment laboratories, thereby enhancing disease diagnostics through improved turn-around time. This study evaluated a panel of 10 surrogate viruses that represent highly pathogenic animal diseases. These results showed that a commercial PrimeStore® molecular transport media (PSMTM) completely inactivated all viruses tested by >99.99%, as determined by infectivity and serial passage assays. However, the detection of viral nucleic acid by qRT-PCR was comparable in PSMTM and control-treated conditions. These results were consistent when viruses were evaluated in the presence of biological material such as sera and cloacal swabs to mimic diagnostic sample conditions for non-avian and avian viruses, respectively. The results of this study may be utilized by diagnostic testing laboratories for highly pathogenic agents affecting animal and human populations. These results may be used to revise guidance for select agent diagnostic testing and the shipment of infectious substances.

Inactivation of Severe Acute Respiratory Coronavirus Virus 2 (SARS-CoV-2) and Diverse RNA and DNA Viruses on Three-Dimensionally Printed Surgical Mask Materials.

BACKGROUND: Personal protective equipment (PPE) is a critical need during the coronavirus disease 2019 (COVID-19) pandemic. Alternative sources of surgical masks, including 3-dimensionally (3D) printed approaches that may be reused, are urgently needed to prevent PPE shortages. Few data exist identifying decontamination strategies to inactivate viral pathogens and retain 3D-printing material integrity. OBJECTIVE: To test viral disinfection methods on 3D-printing materials. METHODS: The viricidal activity of common disinfectants (10% bleach, quaternary ammonium sanitizer, 3% hydrogen peroxide, or 70% isopropanol and exposure to heat (50°C, and 70°C) were tested on four 3D-printed materials used in the healthcare setting, including a surgical mask design developed by the Veterans' Health Administration. Inactivation was assessed for several clinically relevant RNA and DNA pathogenic viruses, including severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and human immunodeficiency virus 1 (HIV-1). RESULTS: SARS-CoV-2 and all viruses tested were completely inactivated by a single application of bleach, ammonium quaternary compounds, or hydrogen peroxide. Similarly, exposure to dry heat (70°C) for 30 minutes completely inactivated all viruses tested. In contrast, 70% isopropanol reduced viral titers significantly less well following a single application. Inactivation did not interfere with material integrity of the 3D-printed materials. CONCLUSIONS: Several standard decontamination approaches effectively disinfected 3D-printed materials. These approaches were effective in the inactivation SARS-CoV-2, its surrogates, and other clinically relevant viral pathogens. The decontamination of 3D-printed surgical mask materials may be useful during crisis situations in which surgical mask supplies are limited.

Semen exosomes inhibit HIV infection and HIV-induced proinflammatory cytokine production independent of the activation state of primary lymphocytes.

Semen exosomes (SE) inhibit HIV infection. However, the effect of SE on cell activation and inflammation remains unknown. We characterized the response of peripheral blood mononuclear cells (PBMCs) from HIV-uninfected and antiretroviral therapy-suppressed HIV-infected (HIV+) subjects to SE. Quiescent PBMCs or T-cell receptor (TCR)-activated PBMCs from HIV- and HIV+ donors were stimulated with SE in the presence/absence of ex vivo HIV infection. In HIV-infected PBMCs, SE did not reactivate HIV, did not induce lymphoblast development, nor increase CD69+/CD25+ numbers. Furthermore, SE inhibited de novo HIV infection without altering cell activation. SE also asynchronously downregulated HIV-inducible IL1ß, IL8, and TNFα and upregulated CXCL10. These data suggest that SE inhibits HIV infection and production of HIV-induced proinflammatory cytokines while preserving lymphocyte activation.

Glycerol Monolaurate, an Analogue to a Factor Secreted by Lactobacillus, Is Virucidal against Enveloped Viruses, Including HIV-1.

The vaginal microbiota influences sexual transmission of human immunodeficiency virus type 1 (HIV-1). Colonization of the vaginal tract is normally dominated by Lactobacillus species. Both Lactobacillus and Enterococcus faecalis may secrete reutericyclin, which inhibits the growth of a variety of pathogenic bacteria. Increasing evidence suggests a potential therapeutic role for an analogue of reutericyclin, glycerol monolaurate (GML), against microbial pathogens. Previous studies using a macaque vaginal simian immunodeficiency virus (SIV) transmission model demonstrated that GML reduces transmission and alters immune responses to infection in vitro Previous studies showed that structural analogues of GML negatively impact other enveloped viruses. We sought to expand understanding of how GML inhibits HIV-1 and other enveloped viruses and show that GML restricts HIV-1 entry post-CD4 engagement at the step of coreceptor binding. Further, HIV-1 and yellow fever virus (YFV) particles were more sensitive to GML interference than particles "matured" by proteolytic processing. We show that high-pressure-liquid-chromatography (HPLC)-purified reutericyclin and reutericyclin secreted by Lactobacillus inhibit HIV-1. These data emphasize the importance and protective nature of the normal vaginal flora during viral infections and provide insights into the antiviral mechanism of GML during HIV-1 infection and, more broadly, to other enveloped viruses.IMPORTANCE A total of 340 million sexually transmitted infections (STIs) are acquired each year. Antimicrobial agents that target multiple infectious pathogens are ideal candidates to reduce the number of newly acquired STIs. The antimicrobial and immunoregulatory properties of GML make it an excellent candidate to fit this critical need. Previous studies established the safety profile and antibacterial activity of GML against both Gram-positive and Gram-negative bacteria. GML protected against high-dose SIV infection and reduced inflammation, which can exacerbate disease, during infection. We found that GML inhibits HIV-1 and other human-pathogenic viruses (yellow fever virus, mumps virus, and Zika virus), broadening its antimicrobial range. Because GML targets diverse infectious pathogens, GML may be an effective agent against the broad range of sexually transmitted pathogens. Further, our data show that reutericyclin, a GML analog expressed by some lactobacillus species, also inhibits HIV-1 replication and thus may contribute to the protective effect of Lactobacillus in HIV-1 transmission.

Semen Extracellular Vesicles From HIV-1-Infected Individuals Inhibit HIV-1 Replication In Vitro, and Extracellular Vesicles Carry Antiretroviral Drugs In Vivo.

BACKGROUND: Extracellular vesicles (EVs) are cell-derived vesicles with diverse functions in intercellular communication including disease and infection, and EVs seem to influence HIV-1 pathogenesis. EVs isolated from HIV-1-uninfected semen (SE), but not blood (BE), contain factors that interfere with HIV-1 infection and replication in target cells. The reason for this dichotomy is unknown. Furthermore, the effect of HIV-1 infection and antiretroviral (ARV) drugs on the anti-HIV-1 effects of SE and BE is unknown. Here, we characterize EVs and EV-free plasma isolated from HIV-infected donor semen and blood and their effects on HIV infection. METHODS: EVs and EV-free plasma were purified from autologous blood and semen of HIV-negative, HIV-infected antiretroviral therapy (ART)-naïve, and HIV-infected ART-treated participants. HIV infection was assessed in a TZM-bl cell reporter system. ARV concentrations were analyzed using liquid chromatography-mass spectrometry. RESULTS: SE isolated from both HIV-negative and HIV-infected, ART-naïve donors inhibited HIV-1 infection, but BE and semen and blood EV-free plasma did not. By contrast, BE, SE, and EV-free plasma from HIV-infected, ART-treated donors inhibited HIV-1. Importantly, exosomes isolated from ART-treated donors contained concentrations of ARV drugs (ART-EVs) at biologically relevant inhibitory levels. CONCLUSIONS: The HIV-1-inhibitory phenotype of SE is independent of donor HIV-1 or ART status, and ARV drugs and their metabolites are SE- and BE-associated in vivo.

Electrostatic Surface Properties of Blood and Semen Extracellular Vesicles: Implications of Sialylation and HIV-Induced Changes on EV Internalization.

Although extracellular vesicle (EV) surface electrostatic properties (measured as zeta potential, ζ-potential) have been reported by many investigators, the biophysical implications of charge and EV origin remains uncertain. Here, we compared the ζ-potential of human blood EVs (BEVs) and semen EVs (SEVs) from 26 donors that were HIV-infected (HIV+, n = 13) or HIV uninfected (HIV-, n = 13). We found that, compared to BEVs that bear neutral surface charge, SEVs were significantly more negatively charged, even when BEVs and SEVs were from the same individual. Comparison of BEVs and SEVs from HIV- and HIV+ groups revealed subtle HIV-induced alteration in the ζ-potential of EVs, with the effect being more significant in SEVs (∆ζ-potential = -8.82 mV, p-value = 0.0062) than BEVs (∆ζ-potential = -1.4 mV, p-value = 0.0462). These observations were validated by differences in the isoelectric point (IEP) of EVs, which was in the order of HIV + SEV ≤ HIV-SEV ≪ HIV + BEV ≤ HIV-BEV. Functionally, the rate and efficiency of SEV internalization by the human cervical epithelial cell line, primary peripheral blood lymphocytes, and primary blood-derived monocytes were significantly higher than those of BEVs. Mechanistically, removal of sialic acids from the surface of EVs using neuraminidase treatment significantly decreased SEV's surface charge, concomitant with a substantial reduction in SEV's internalization. The neuraminidase effect was independent of HIV infection and insignificant for BEVs. Finally, these results were corroborated by enrichment of glycoproteins in SEVs versus BEVs. Taken together, these findings uncover fundamental tissue-specific differences in surface electrostatic properties of EVs and highlight the critical role of surface charge in EV/target cell interactions.

Isolation of Exosomes from Semen for in vitro Uptake and HIV-1 Infection Assays.

Exosomes are membranous extracellular nanovesicles of endocytic origin. Exosomes are known to carry host and pathogen-derived genomic, proteomic, lipidomic cargos and other extraneous molecules. Exosomes are secreted by diverse cell types into the extracellular milieu and are subsequently internalized by recipient neighboring or distal cells. Upon internalization, exosomes condition recipient cells by donating their cargos and/or activating various signal transduction pathways, consequently regulating physiological and pathophysiological processes. Exosomes facilitate intercellular communication, modulate cellular phenotype, and regulate microbial pathogenesis. We have previously shown that semen exosomes (SE) inhibit HIV-1 replication in various cell types. Here, we describe detailed protocols for characterizing SE. This protocol can be adapted or modified and used for evaluation of other extracellular vesicles of interest.

Effect of prolonged freezing of semen on exosome recovery and biologic activity.

Exosomes are important vehicles of intercellular communication that shape host responses to physiologic, tumorigenic, and pathogenic conditions. The composition and function of exosomes are dynamic and depends on the state and condition of the cellular source. In prior work, we found that semen exosomes (SE) from healthy donors who do not use illicit drugs potently inhibit HIV-1. Following semen donation, specimens are either used immediately or frozen for use at a later time. It has been shown that short-term freezing of semen has no effect on SE-mediated HIV-1 inhibition. However, the effect of illicit drugs and prolonged freezing on SE bioactivity is unknown. Here, we show preservation of SE physical properties, (morphology, concentration, intensity/size) irrespective of illicit drug use or duration of semen freezing. Interestingly, illicit drugs and prolonged freezing decreased the levels of SE-bound CD63/CD9 and acetylcholinesterase activity respectively. Furthermore, we show differential effects of illicit drug use and prolonged freezing on SE-mediated HIV-1 inhibition. Our results highlight the importance of the source of SE and condition of semen storage on SE content and function. In-depth evaluation of donor drug-use and duration of semen storage on SE cargo and bioactivity will advance our understanding of SE composition and function.