Sequential early-life viral infections modulate the microbiota and adaptive immune responses to systemic and mucosal vaccination.

Increasing evidence points to the microbial exposome as a critical factor in maturing and shaping the host immune system, thereby influencing responses to immune challenges such as infections or vaccines. To investigate the effect of early-life viral exposures on immune development and vaccine responses, we inoculated mice with six distinct viral pathogens in sequence beginning in the neonatal period, and then evaluated their immune signatures before and after intramuscular or intranasal vaccination against SARS-CoV-2. Sequential viral infection drove profound changes in all aspects of the immune system, including increasing circulating leukocytes, altering innate and adaptive immune cell lineages in tissues, and markedly influencing serum cytokine and total antibody levels. Beyond changes in the immune responses, these exposures also modulated the composition of the endogenous intestinal microbiota. Although sequentially-infected mice exhibited increased systemic immune activation and T cell responses after intramuscular and intranasal SARS-CoV-2 immunization, we observed decreased vaccine-induced antibody responses in these animals. These results suggest that early-life viral exposures are sufficient to diminish antibody responses to vaccination in mice, and highlight the potential importance of considering prior microbial exposures when investigating vaccine responses.

Glycan cross-feeding supports mutualism between Fusobacterium and the vaginal microbiota.

Women with bacterial vaginosis (BV), an imbalance of the vaginal microbiome, are more likely to be colonized by potential pathogens such as Fusobacterium nucleatum, a bacterium linked with intrauterine infection and preterm birth. However, the conditions and mechanisms supporting pathogen colonization during vaginal dysbiosis remain obscure. We demonstrate that sialidase activity, a diagnostic feature of BV, promoted F. nucleatum foraging and growth on mammalian sialoglycans, a nutrient resource that was otherwise inaccessible because of the lack of endogenous F. nucleatum sialidase. In mice with sialidase-producing vaginal microbiotas, mutant F. nucleatum unable to consume sialic acids was impaired in vaginal colonization. These experiments in mice also led to the discovery that F. nucleatum may also "give back" to the community by reinforcing sialidase activity, a biochemical feature of human dysbiosis. Using human vaginal bacterial communities, we show that F. nucleatum supported robust outgrowth of Gardnerella vaginalis, a major sialidase producer and one of the most abundant organisms in BV. These results illustrate that mutually beneficial relationships between vaginal bacteria support pathogen colonization and may help maintain features of dysbiosis. These findings challenge the simplistic dogma that the mere absence of "healthy" lactobacilli is the sole mechanism that creates a permissive environment for pathogens during vaginal dysbiosis. Given the ubiquity of F. nucleatum in the human mouth, these studies also suggest a possible mechanism underlying links between vaginal dysbiosis and oral sex.

African American Clergy Recommendations to Enhance the Federal Plan to End the HIV Epidemic: A Qualitative Study.

African Americans in the southern United States continue to be disproportionately affected by HIV. Although faith-based organizations (FBOs) play important roles in the social fabric of African American communities, few HIV screening, care, and PrEP promotion efforts harness the power of FBOs. We conducted 11 focus groups among 57 prominent African American clergy from Arkansas, Mississippi, and Alabama. We explored clergy knowledge about the Ending the HIV Epidemic: A Plan for America (EHE); normative recommendations for how clergy can contribute to EHE; and how clergy can enhance the HIV care continua and PrEP. We explored how clergy have responded to the COVID-19 crisis, and lessons learned from pandemic experiences that are relevant for HIV programs. Clergy reported a moral obligation to participate in the response to the HIV epidemic and were willing to support efforts to expand HIV screening, treatment, PrEP and HIV care. Few clergy were familiar with EHE, U = U and TasP. Many suggested developing culturally tailored messages and were willing to lend their voices to social marketing efforts to destigmatize HIV and promote uptake of biomedical interventions. Nearly all clergy believed technical assistance with biomedical HIV prevention and care interventions would enhance their ability to create partnerships with local community health centers. Partnering with FBOs presents important and unique opportunities to reduce HIV disparities. Clergy want to participate in the EHE movement and need federal resources and technical assistance to support their efforts to bridge community activities with biomedical prevention and care programs related to HIV. The COVID-19 pandemic presents opportunities to build important infrastructure related to these goals.

"Shades of risk": Understanding current PrEP users' sexually transmitted infection perceptions.

ABSTRACTPre-exposure prophylaxis (PrEP) is a safe and effective HIV prevention strategy. Given the possibility of increased sexual risk-taking and acquisition of other sexually transmitted infections (STIs) following PrEP initiation, it is important to explore STI risk perceptions both before and after PrEP initiation to understand the extent to which these perceptions inform decisions to engage in condomless sex. Semi-structured qualitative interviews were conducted with men who have sex with men currently using PrEP (n = 30). Prior to analysis, PrEP users were categorized into four subgroups based on condom use behavior post-PrEP initiation: (1) condom continuers (2) condomless sex continuers, (3) condomless sex increasers, and (4) condomless sex decreasers. Thematic analysis revealed two major themes that elucidated differences in (1) the appraisal of HIV risk relative to other STIs and (2) the importance of partner communication in determining STI risk perceptions by subgroup. Most PrEP users demonstrated no behavioral change after PrEP initiation. Those engaging in condomless sex prior to PrEP initiation also continued that behavior while taking PrEP. Results of this study support a tailored approach to PrEP counseling based on individual STI risk appraisal and motivations to initiate and continue PrEP.

The need for targeted behavioural HIV-related interventions for transgender women in India: A scoping review.

Background & objectives: Transgender women (TGW) in India are at high risk of HIV infection. Despite behavioural interventions aimed at reducing HIV risk, no literature synthesis exists so far to evaluate their potential for reducing HIV incidence in India This review was aimed to identify and evaluate HIV-focussed behaviour change interventions for TGW in India. Methods: Literature from three databases were reviewed up to June 2, 2021, for studies describing behavioural interventions for HIV prevention among TGW in India. The inclusion criteria were studies that included TGW and reported intervention effects on HIV prevention-related behaviour. Data were analyzed descriptively. Results: Of the 146 articles screened, only three met the inclusion criteria. All three interventions were at the open pilot trial stage and included other high-risk groups (e.g. men who have sex with men). The interventions used behavioural counselling, increased sexually transmitted infection screening and sexual healthcare visits and leveraged community-based organizations to improve the outcomes. All these interventions showed modest improvements in health-seeking behaviour and access to services. However, none specifically targeted TGW. Interpretation & conclusions: The scoping review highlights the need for behavioural interventions for HIV prevention tailored to TGW in India. This study emphasizes the need for research to move to the next stage of intervention development and testing utilizing more rigorous evaluation methods, such as a randomized controlled trial.

Transitioning from Face to Face to the Digital Space: Best Practices and Lessons Learned Leveraging Technology to Conduct HIV-Focused Interventions.

Introduction: Coronavirus disease 2019 (COVID-19) has impacted researchers' ability to continue to deliver HIV prevention and treatment interventions face to face. Although telehealth has been an important strategy to maintain research operations during the current pandemic, participants at increased risk of or living with HIV are often at higher risk of also experiencing poverty, housing instability, and other challenges that may present obstacles to successful remote delivery. Methods: We provide descriptions of remote adaptations to two randomized controlled efficacy trials of behavioral interventions for primary and secondary HIV prevention with descriptive enrollment and retention data. Results and Conclusions: Best practices for implementing telemedicine and e-health procedures are discussed, including procedures for addressing remote participation barriers (economic, health literacy, etc.) and other challenges, such as building rapport and staff support (NCT03092531 and NCT03175159).

Gardnerella vaginalis promotes group B Streptococcus vaginal colonization, enabling ascending uteroplacental infection in pregnant mice.

BACKGROUND: Group B Streptococcus is a common vaginal bacterium and the leading cause of invasive fetoplacental infections. Group B Streptococcus in the vagina can invade through the cervix to cause ascending uteroplacental infections or can be transmitted to the neonate during vaginal delivery. Some studies have found that women with a "dysbiotic" polymicrobial or Lactobacillus-depleted vaginal microbiota are more likely to harbor group B Streptococcus. Gardnerella vaginalis is often the most abundant bacteria in the vaginas of women with dysbiosis, while being detected at lower levels in most other women, and has been linked with several adverse pregnancy outcomes. Mouse models of group B Streptococcus and Gardnerella vaginalis colonization have been reported but, to the best of our knowledge, the two have not been studied together. The overarching idea driving this study is that certain members of the dysbiotic vaginal microbiota, such as Gardnerella vaginalis, may directly contribute to the increased rate of group B Streptococcus vaginal colonization observed in women with vaginal dysbiosis. OBJECTIVE: We used a mouse model to test the hypothesis that vaginal exposure to Gardnerella vaginalis may facilitate colonization and/or invasive infection of the upper reproductive tract by group B Streptococcus during pregnancy. STUDY DESIGN: Timed-pregnant mice were generated using an allogeneic mating strategy with BALB/c males and C57Bl/6 females. Dams were vaginally inoculated at gestational day 14 with group B Streptococcus alone (using a 10-fold lower dose than previously reported models) or coinoculated with group B Streptococcus and Gardnerella vaginalis. Bacterial titers were enumerated in vaginal, uterine horn, and placental tissues at gestational day 17. The presence (Fisher exact tests) and levels (Mann-Whitney U tests) of bacterial titers were compared between mono- and coinoculated dams in each compartment. Relative risks were calculated for outcomes that occurred in both groups. Tissue samples were also examined for evidence of pathophysiology. RESULTS: Inoculation of pregnant mice with 107 group B Streptococcus alone did not result in vaginal colonization or ascending infection. In contrast, coinoculation of group B Streptococcus with Gardnerella vaginalis in pregnant mice resulted in a 10-fold higher risk of group B Streptococcus vaginal colonization (relative risk, 10.31; 95% confidence interval, 2.710-59.04; P=.0006 [Fisher exact test]). Ascending group B Streptococcus infection of the uterus and placenta occurred in approximately 40% of coinoculated animals, whereas none of those receiving group B Streptococcus alone developed uterine or placental infections. Immunofluorescence microscopy revealed group B Streptococcus in both the maternal and fetal sides of the placenta. Histologic inflammation and increased proinflammatory cytokines were evident in the setting of group B Streptococcus placental infection. Interestingly, placentas from dams exposed to group B Streptococcus and Gardnerella vaginalis, but without recoverable vaginal or placental bacteria, displayed distinct histopathologic features and cytokine signatures. CONCLUSION: These data suggest that Gardnerella vaginalis vaginal exposure can promote group B Streptococcus vaginal colonization, resulting in a greater likelihood of invasive perinatal group B Streptococcus infections. These findings suggest that future clinical studies should examine whether the presence of Gardnerella vaginalis is a risk factor for group B Streptococcus vaginal colonization in women. Because Gardnerella vaginalis can also be present in women without bacterial vaginosis, these findings may be relevant both inside and outside of the context of vaginal dysbiosis.

Associations between the vaginal microbiome and Candida colonization in women of reproductive age.

BACKGROUND: The composition of bacteria within the vaginal microbiome has garnered a lot of recent attention and has been associated with reproductive health and disease. Despite the common occurrence of yeast (primarily Candida) within the vaginal microbiome, there is still an incomplete picture of relationships between yeast and bacteria (especially lactobacilli), as well as how such associations are governed. Such relationships could be important to a more holistic understanding of the vaginal microbiome and its connection to reproductive health. OBJECTIVE: The objective of the study was to perform molecular characterization of clinical specimens to define associations between vaginal bacteria (especially Lactobacillus species) and Candida colonization. In vitro studies were conducted to test the 2 most common dominant Lactobacillus species (Lactobacillus crispatus and Lactobacillus iners) in their ability to inhibit Candida growth and to examine the basis for such inhibition. STUDY DESIGN: A nested cross-sectional study of reproductive-age women from the Contraceptive CHOICE Project was conducted. Vaginal swabs from 299 women were selected to balance race and bacterial vaginosis status, resulting in a similar representation of black and white women in each of the 3 Nugent score categories (normal [0-3], intermediate [4-6], and bacterial vaginosis [7-10]). Sequencing of the 16S ribosomal gene (V4 region) was used to determine the dominant Lactobacillus species present (primarily Lactobacillus iners and Lactobacillus crispatus), defined as >50% of the community. Subjects without dominance by a single Lactobacillus species were classified as Diverse. A Candida-specific quantitative polymerase chain reaction targeting the internally transcribed spacer 1 was validated using vaginal samples collected from a second cohort of women and used to assess Candida colonization. Two hundred fifty-five nonpregnant women with sufficient bacterial biomass for analysis were included in the final analysis. Generalized linear models were used to evaluate associations between Lactobacillus dominance, sociodemographic and risk characteristics, and vaginal Candida colonization. In separate in vitro studies, the potential of cell-free supernatants from Lactobacillus crispatus and Lactobacillus iners cultures to inhibit Candida growth was evaluated. RESULTS: Forty-two women (16%) were vaginally colonized with Candida. Microbiomes characterized as Diverse (38%), Lactobacillus iners-dominant (39%), and Lactobacillus crispatus-dominant (20%) were the most common. The microbiome, race, and Candida colonization co-varied with a higher prevalence of Candida among black women and Lactobacillus iners-dominant communities compared with white women and Lactobacillus crispatus-dominant communities. Lactobacillus iners-dominant communities were more likely to harbor Candida than Lactobacillus crispatus-dominant communities (odds ratio, 2.85, 95% confidence interval, 1.03-7.21; Fisher exact test, P = .048). In vitro, Lactobacillus crispatus produced greater concentrations of lactic acid and exhibited significantly more pH-dependent growth inhibition of Candida albicans, suggesting a potential mechanism for the clinical observations. CONCLUSION: In nonpregnant women, Lactobacillus iners-dominant communities were significantly more likely to harbor Candida than Lactobacillus crispatus-dominant communities, suggesting that Lactobacillus species have different relationships with Candida. In vitro experiments indicate that Lactobacillus crispatus may impede Candida colonization more effectively than Lactobacillus iners through a greater production of lactic acid.

Is it disgusting or am I just easily disgusted? The relation between situational disgust, dispositional disgust, and colonoscopy intentions.

OBJECTIVE: While early detection is an effective way to reduce mortality from colorectal cancer, screening rates are low. An underlying factor in screening completion failure may be experiences of disgust when learning about screening and/or dispositional disgust. METHOD: Participants recruited via Amazon MTurk (N = 296) read information about colonoscopy and completed an online survey assessing both dispositional forms of disgust (i.e. trait disgust and disgust sensitivity) and situational forms, including state disgust and disgust associated with colonoscopy. Participants reported intentions to discuss colonoscopy with a provider and to prepare for and complete screening. RESULTS: Greater state disgust and the degree to which one associated disgust with colonoscopy predicted lower screening, preparation and provider discussion intentions. By contrast, neither trait disgust nor disgust sensitivity was associated with intentions. Both disgust sensitivity and trait disgust moderated the state disgust to intentions relation. CONCLUSIONS: This is one of few investigations of disgust examining the relation between specific types and colonoscopy intentions. Screening uptake may be improved by identifying specific components of disgust that have an effect on colonoscopy intentions. Future work focusing on the interplay between different disgust mechanisms as they relate to colonoscopy behaviour is important for intervention development.

Affective components of perceived risk mediate the relation between cognitively-based perceived risk and colonoscopy screening.

Perceived risk is a common component of health decision making theory. When affective components of risk are assessed as predictors of a behavior, they are usually examined separately from cognitive components. Less frequently examined are more complex interplays between affect and cognition. We hypothesized that cognitive and affective risk components would both have direct effects on colonoscopy behavior/intentions and that affective components would mediate the relationship of cognitively-based perceived risk to colonoscopy screening. In two secondary analyses, participants reported their cognitive and affective perceived risk for colorectal cancer, past colonoscopy behavior, and future screening intentions. In both studies, cognitive and affective risk components were associated with increased screening behavior/intentions and cognitive risk components were mediated through affective risk. Given the impact of early detection on colorectal cancer prevention, educational strategies highlighting both components of risk may be important to increase screening rates.

Sexual orientation and social network size moderate associations between stigma and problematic alcohol use among male sex workers in the US Northeast: an observational study.

Background Stigma is associated with poor health among sexual minority individuals. However, no studies have examined the relationship between stigma and problematic drinking among male sex workers (MSWs). This study examined the relationship between sex work stigma and problematic alcohol use among MSWs. METHODS: Using baseline data from a cohort of 98 MSWs in the US Northeast enrolled between 2015 and 2016, we used logistic regression to examine associations between sex work stigma and hazardous drinking (Alcohol Use Disorders Identification Test (AUDIT) score ≥8) and sex work while drunk, and tested whether sexual orientation (gay vs non-gay identified) and social network size moderated these associations. RESULTS: Almost half the sample (n = 46; 44%) reported hazardous drinking and 56 MSWs (57%) reported engaging in sex work while drunk. Sex work stigma was associated with hazardous drinking (adjusted odds ratio (aOR) 1.2, 95% confidence interval (CI) 1.05-1.36). Sexual orientation marginally moderated this relationship (P = 0.07), such that it was only significant among gay-identified MSWs (aOR 1.91, 95% CI 1.11-3.28), not among non-gay MSW. Similarly, sexual orientation moderated the effect of sex work stigma on sex work while drunk (P = 0.02), which was only significant among gay-identified MSWs (aOR 1.65, 95% CI 1.05-1.60). Social network size also moderated the effect of sex work stigma on sex work while drunk (P = 0.02), which was only significant among MSWs with small networks (aOR 1.26, 95% CI 1.00-1.58), suggesting large networks can be protective. CONCLUSIONS: Gay MSWs may be particularly vulnerable to alcohol-related effects of stigma. Future interventions should consider engaging social networks to curb problematic drinking among MSWs.

Predicting Colonoscopy Screening Behavior and Future Screening Intentions for African Americans Older than 50 Years.

African Americans experience a disproportionate burden of morbidity and mortality from colorectal cancer, which may be due to low adherence to screening recommendations. Previous studies have found relationships between decision-making factors and screening behavior, but few have looked at both cognitive and affective factors or within a specifically African American sample. To better understand determinants that drive screening behavior, this study examines affective, cognitive, and social variables as predictors of colonoscopy in an age-eligible African American population. Participants completed surveys assessing affective associations with colonoscopy, perceived benefits and barriers, self-efficacy, knowledge, fear of colonoscopy, perceived risk, and colorectal cancer worry and fear. Regression analysis was used to model decision-making constructs as predictors of screening behavior/intentions. Affective, cognitive, and health care experience variables predicted colonoscopy completion and intentions. Provider-level factors and previous cancer screenings predicted prior screening only, but not intentions. Affective and cognitive components of perceived risk were associated with decreased likelihood of colonoscopy behavior, but increased likelihood of colonoscopy intentions. These findings suggest that colonoscopy decision making involves a complex array of both cognitive and affective determinants. This work extends our knowledge of colorectal cancer screening decision making by evaluating the effects of these multiple determinants on screening behavior in an African American sample. Future work exploring the interplay of affect and cognitions as influences on colonoscopy decision making and how health care experiences may moderate this effect is needed to develop effective intervention approaches and reduce screening disparities.

Ibuprofen slows migration and inhibits bowel colonization by enteric nervous system precursors in zebrafish, chick and mouse.

Hirschsprung Disease (HSCR) is a potentially deadly birth defect characterized by the absence of the enteric nervous system (ENS) in distal bowel. Although HSCR has clear genetic causes, no HSCR-associated mutation is 100% penetrant, suggesting gene-gene and gene-environment interactions determine HSCR occurrence. To test the hypothesis that certain medicines might alter HSCR risk we treated zebrafish with medications commonly used during early human pregnancy and discovered that ibuprofen caused HSCR-like absence of enteric neurons in distal bowel. Using fetal CF-1 mouse gut slice cultures, we found that ibuprofen treated enteric neural crest-derived cells (ENCDC) had reduced migration, fewer lamellipodia and lower levels of active RAC1/CDC42. Additionally, inhibiting ROCK, a RHOA effector and known RAC1 antagonist, reversed ibuprofen effects on migrating mouse ENCDC in culture. Ibuprofen also inhibited colonization of Ret+/- mouse bowel by ENCDC in vivo and dramatically reduced bowel colonization by chick ENCDC in culture. Interestingly, ibuprofen did not affect ENCDC migration until after at least three hours of exposure. Furthermore, mice deficient in Ptgs1 (COX 1) and Ptgs2 (COX 2) had normal bowel colonization by ENCDC and normal ENCDC migration in vitro suggesting COX-independent effects. Consistent with selective and strain specific effects on ENCDC, ibuprofen did not affect migration of gut mesenchymal cells, NIH3T3, or WT C57BL/6 ENCDC, and did not affect dorsal root ganglion cell precursor migration in zebrafish. Thus, ibuprofen inhibits ENCDC migration in vitro and bowel colonization by ENCDC in vivo in zebrafish, mouse and chick, but there are cell type and strain specific responses. These data raise concern that ibuprofen may increase Hirschsprung disease risk in some genetically susceptible children.

CD44 and TLR4 mediate hyaluronic acid regulation of Lgr5+ stem cell proliferation, crypt fission, and intestinal growth in postnatal and adult mice.

Hyaluronic acid, a glycosaminoglycan in the extracellular matrix, binds to CD44 and Toll-like receptor 4 (TLR4). We previously addressed the role of hyaluronic acid in small intestinal and colonic growth in mice. We addressed the role of exogenous hyaluronic acid by giving hyaluronic acid intraperitoneally and the role of endogenous hyaluronic acid by giving PEP-1, a peptide that blocks hyaluronic acid binding to its receptors. Exogenous hyaluronic acid increased epithelial proliferation but had no effect on intestinal length. PEP-1 resulted in a shortened small intestine and colon and diminished epithelial proliferation. In the current study, we sought to determine whether the effects of hyaluronic acid on growth were mediated by signaling through CD44 or TLR4 by giving exogenous hyaluronic acid or PEP-1 twice a week from 3-8 wk of age to wild-type, CD44(-/-), and TLR4(-/-) mice. These studies demonstrated that signaling through both CD44 and TLR4 were important in mediating the effects of hyaluronic acid on growth in the small intestine and colon. Extending our studies to early postnatal life, we assessed the effects of exogenous hyaluronic acid and PEP-1 on Lgr5(+) stem cell proliferation and crypt fission. Administration of PEP-1 to Lgr5(+) reporter mice from postnatal day 7 to day 14 decreased Lgr5(+) cell proliferation and decreased crypt fission. These studies indicate that endogenous hyaluronic acid increases Lgr5(+) stem cell proliferation, crypt fission, and intestinal lengthening and that these effects are dependent on signaling through CD44 and TLR4.

IDO1 metabolites activate ß-catenin signaling to promote cancer cell proliferation and colon tumorigenesis in mice.

BACKGROUND & AIMS: Indoleamine 2,3 dioxygenase-1 (IDO1) catabolizes tryptophan along the kynurenine pathway. Although IDO1 is expressed in inflamed and neoplastic epithelial cells of the colon, its role in colon tumorigenesis is not well understood. We used genetic and pharmacologic approaches to manipulate IDO1 activity in mice with colitis-associated cancer and human colon cancer cell lines. METHODS: C57Bl6 wild-type (control), IDO1-/-, Rag1-/-, and Rag1/IDO1 double-knockout mice were exposed to azoxymethane and dextran sodium sulfate to induce colitis and tumorigenesis. Colitis severity was assessed by measurements of disease activity, cytokine levels, and histologic analysis. In vitro experiments were conducted using HCT 116 and HT-29 human colon cancer cells. 1-methyl tryptophan and small interfering RNA were used to inhibit IDO1. Kynurenine pathway metabolites were used to simulate IDO1 activity. RESULTS: C57Bl6 mice given pharmacologic inhibitors of IDO1 and IDO1-/- mice had lower tumor burdens and reduced proliferation in the neoplastic epithelium after administration of dextran sodium sulfate and azoxymethane than control mice. These reductions also were observed in Rag1/IDO1 double-knockout mice compared with Rag1-/- mice (which lack mature adaptive immunity). In human colon cancer cells, blockade of IDO1 activity reduced nuclear and activated ß-catenin, transcription of its target genes (cyclin D1 and Axin2), and, ultimately, proliferation. Exogenous administration of IDO1 pathway metabolites kynurenine and quinolinic acid led to activation of ß-catenin and proliferation of human colon cancer cells, and increased tumor growth in mice. CONCLUSIONS: IDO1, which catabolizes tryptophan, promotes colitis-associated tumorigenesis in mice, independent of its ability to limit T-cell-mediated immune surveillance. The epithelial cell-autonomous survival advantage provided by IDO1 to colon epithelial cells indicate its potential as a therapeutic target.

The neonatal Fc receptor and DPP4 are human astrovirus receptors.

Human astroviruses (HAstV) are major global causes of gastroenteritis, but little is known about host factors required for their cellular entry. Here, we utilized complementary CRISPR-Cas9-based knockout and activation screening approaches and identified neonatal Fc receptor (FcRn) and dipeptidyl-peptidase IV (DPP4) as entry factors for HAstV infection of human intestinal epithelial cells. Disruption of FcRn or DPP4 reduced HAstV infection in permissive cells and, reciprocally, overexpression of these factors in non-permissive cells was sufficient to promote infection. We observed direct binding between FcRn and HAstV virions as well as purified spike protein. Finally, inhibitors for DPP4 and FcRn currently in clinical use prevent HAstV infection in cell lines and primary human enteroids. Thus, our results reveal mechanisms of HAstV entry as well as druggable targets. One-Sentence Summary: Targeting FcRn or DPP4 using available therapies effectively prevents human astrovirus infection in human enteroid cultures.

Sequential early-life viral infections modulate the microbiota and adaptive immune responses to systemic and mucosal vaccination.

Increasing evidence points to the microbial exposome as a critical factor in maturing and shaping the host immune system, thereby influencing responses to immune challenges such as infections or vaccines. To investigate the effect of early-life viral exposures on immune development and vaccine responses, we inoculated mice with six distinct viral pathogens in sequence beginning in the neonatal period, and then evaluated their immune signatures before and after intramuscular or intranasal vaccination against SARS-CoV-2. Sequential viral infection drove profound changes in all aspects of the immune system, including increasing circulating leukocytes, altering innate and adaptive immune cell lineages in tissues, and markedly influencing serum cytokine and total antibody levels. Beyond these immune responses changes, these exposures also modulated the composition of the endogenous intestinal microbiota. Although sequentially-infected mice exhibited increased systemic immune activation and T cell responses after intramuscular and intranasal SARS-CoV-2 immunization, we observed decreased vaccine-induced antibody responses in these animals. These results suggest that early-life viral exposures are sufficient to diminish antibody responses to vaccination in mice, and highlight their potential importance of considering prior microbial exposures when investigating vaccine responses.

IFN-λ derived from nonsusceptible enterocytes acts on tuft cells to limit persistent norovirus.

Norovirus is a leading cause of epidemic viral gastroenteritis, with no currently approved vaccines or antivirals. Murine norovirus (MNoV) is a well-characterized model of norovirus pathogenesis in vivo, and persistent strains exhibit lifelong intestinal infection. Interferon-λ (IFN-λ) is a potent antiviral that rapidly cures MNoV. We previously demonstrated that IFN-λ signaling in intestinal epithelial cells (IECs) controls persistent MNoV, and here demonstrate that IFN-λ acts on tuft cells, the exclusive site of MNoV persistence, to limit infection. While interrogating the source of IFN-λ to regulate MNoV, we confirmed that MDA5-MAVS signaling, required for IFN-λ induction to MNoV in vitro, controls persistent MNoV in vivo. We demonstrate that MAVS in IECs and not immune cells controls MNoV. MAVS in nonsusceptible enterocytes, but not in tuft cells, restricts MNoV, implicating noninfected cells as the IFN-λ source. Our findings indicate that host sensing of MNoV is distinct from cellular tropism, suggesting intercellular communication between IECs for antiviral signaling induction in uninfected bystander cells.

A Neighborhood-level analysis of mental health distress and income inequality as quasi-longitudinal risk of reported COVID-19 infection and mortality outcomes in Chicago.

Extant literature investigates the impact of COVID-19 on mental health outcomes, however there is a paucity of work examining mental health distress as a risk factor for COVID-19 outcomes. While systemic variables like income inequality relate to both mental health and COVID-19, more work is needed to test theoretically informed models including such variables. Using a social-ecological framework, we aimed to address these gaps in the literature by conducting a neighborhood-level analysis of potential mental health distress and systemic- (income inequality) level predictors of reported COVID-19 infection and mortality over time in Chicago. Neighborhood-level comparisons revealed differences in mental health distress, income inequality, and reported COVID-19 mortality, but not reported COVID-19 infection. Specifically, Westside and Southside neighborhoods generally reported higher levels of mental health distress and greater concentration of poverty. The Central neighborhood showed a decline in reported mortality rates over time. Multi-level negative binomial models established that Zip-codes with greater mental health distress were at increased reported COVID-19 infection risk, yet lower mortality risk; Zip-codes with more poverty were at increased reported COVID-19 infection risk, yet lower mortality risk; and Zip-codes with the highest percentage of People of Color were at decreased risk of reported COVID-19 mortality. Taken together, these findings substantiate Chicago neighborhood-level disparities in mental health distress, income inequality, and reported COVID-19 mortality; identify unique differential associations of mental health distress and income inequality to reported COVID-19 infection and reported mortality risk; and, offer an alternative lens towards understanding COVID-19 outcomes in terms of race/ethnicity.

Structural Equation Modeling of Stigma and HIV Prevention Clinical Services Among Transgender and Gender Diverse Adults: The Mediating Role of Substance Use and HIV Sexual Risk.

BACKGROUND: Transgender and gender diverse (TGD) adults experience high levels of stigma that contributes to elevated substance use and HIV sexual risk behaviors. Despite higher burdens of substance use and HIV compared to cisgender adults, TGD individuals may be less likely to engage in health care to avoid further discrimination. SETTING: This analysis included 529 TGD adults in Massachusetts and Rhode Island who were HIV negative or had an unknown HIV serostatus and were purposively sampled between March and August 2019. METHODS: We used structural equation modeling to test whether substance use, HIV sexual risk behaviors (ie, condom use, sex work, and multiple partners), and receiving gender-affirming hormone therapy mediate any observed association between TGD-related stigma and utilization of HIV prevention clinical services (ie, HIV prevention programs, PrEP use, and HIV testing). RESULTS: Substance use and HIV sexual risk mediated the relationship between TGD-related stigma and utilization of HIV prevention clinical services (ß = 0.08; 95% CI = 0.05, 0.17; P = 0.03 and ß = 0.26; 95% CI = 0.14 to 0.37; P < 0.001). Having a hormone therapy prescription was not a mediator between TGD-related stigma and HIV prevention clinical services. CONCLUSIONS: Future interventions that aim to improve HIV prevention clinical services among TGD adults should consider the impact of TGD-related stigma on participants' substance use and sexual risk behaviors. These efforts require that health care organizations and community organizations make a deliberate investment in the reach and success of interventions and programs.