Whole-genome sequences of Campylobacter coli and Campylobacter jejuni isolates from rhesus macaques (Macaca mulatta) with and without intestinal disease.

Campylobacter jejuni or Campylobacter coli infection can lead to post-infectious irritable bowel syndrome in humans and may produce a similar syndrome in rhesus macaques (Macaca mulatta). We report the complete genomes of 8 C. jejuni isolates and 103 C. coli isolates obtained from rhesus macaques with and without intestinal disease.

The NADPH oxidase 2 subunit p47phox binds to the WAVE regulatory complex and p22phox in a mutually exclusive manner.

The actin cytoskeleton and reactive oxygen species (ROS) both play crucial roles in various cellular processes. Previous research indicated a direct interaction between two key components of these systems: the WAVE1 subunit of the WAVE regulatory complex (WRC), which promotes actin polymerization and the p47phox subunit of the NADPH oxidase 2 complex (NOX2), which produces ROS. Here, using carefully characterized recombinant proteins, we find that activated p47phox uses its dual Src homology 3 domains to bind to multiple regions within the WAVE1 and Abi2 subunits of the WRC, without altering WRC's activity in promoting Arp2/3-mediated actin polymerization. Notably, contrary to previous findings, p47phox uses the same binding pocket to interact with both the WRC and the p22phox subunit of NOX2, albeit in a mutually exclusive manner. This observation suggests that when activated, p47phox may separately participate in two distinct processes: assembling into NOX2 to promote ROS production and engaging with WRC to regulate the actin cytoskeleton.

Identification of New Markers of Angiogenic Sprouting Using Transcriptomics: New Role for RND3.

BACKGROUND: New blood vessel formation requires endothelial cells to transition from a quiescent to an invasive phenotype. Transcriptional changes are vital for this switch, but a comprehensive genome-wide approach focused exclusively on endothelial cell sprout initiation has not been reported. METHODS: Using a model of human endothelial cell sprout initiation, we developed a protocol to physically separate cells that initiate the process of new blood vessel formation (invading cells) from noninvading cells. We used this model to perform multiple transcriptomics analyses from independent donors to monitor endothelial gene expression changes. RESULTS: Single-cell population analyses, single-cell cluster analyses, and bulk RNA sequencing revealed common transcriptomic changes associated with invading cells. We also found that collagenase digestion used to isolate single cells upregulated the Fos proto-oncogene transcription factor. Exclusion of Fos proto-oncogene expressing cells revealed a gene signature consistent with activation of signal transduction, morphogenesis, and immune responses. Many of the genes were previously shown to regulate angiogenesis and included multiple tip cell markers. Upregulation of SNAI1 (snail family transcriptional repressor 1), PTGS2 (prostaglandin synthase 2), and JUNB (JunB proto-oncogene) protein expression was confirmed in invading cells, and silencing JunB and SNAI1 significantly reduced invasion responses. Separate studies investigated rounding 3, also known as RhoE, which has not yet been implicated in angiogenesis. Silencing rounding 3 reduced endothelial invasion distance as well as filopodia length, fitting with a pathfinding role for rounding 3 via regulation of filopodial extensions. Analysis of in vivo retinal angiogenesis in Rnd3 heterozygous mice confirmed a decrease in filopodial length compared with wild-type littermates. CONCLUSIONS: Validation of multiple genes, including rounding 3, revealed a functional role for this gene signature early in the angiogenic process. This study expands the list of genes associated with the acquisition of a tip cell phenotype during endothelial cell sprout initiation.

Neurometabolic profile of the amygdala in smokers assessed with 1H-magnetic resonance spectroscopy.

Tobacco smoking is one of the main causes of premature death worldwide and quitting success remains low, highlighting the need to understand the neurobiological mechanisms underlying relapse. Preclinical models have shown that the amygdala and glutamate play an important role in nicotine addiction. The aims of this study were to compare glutamate and other metabolites in the amygdala between smokers and controls, and between different smoking states. Furthermore, associations between amygdalar metabolite levels and smoking characteristics were explored. A novel non-water-suppressed proton magnetic resonance spectroscopy protocol was applied to quantify neurometabolites in 28 male smokers (≥15 cigarettes/day) and 21 non-smoking controls, matched in age, education, verbal IQ, and weekly alcohol consumption. Controls were measured once (baseline) and smokers were measured in a baseline state (1-3 h abstinence), during withdrawal (24 h abstinence) and in a satiation state (directly after smoking). Baseline spectroscopy data were compared between groups by independent t-tests or Mann-Whitney-U tests. Smoking state differences were investigated by repeated-measures analyses of variance (ANOVAs). Associations between spectroscopy data and smoking characteristics were explored using Spearman correlations. Good spectral quality, high anatomical specificity (98% mean gray matter) and reliable quantification of most metabolites of interest were achieved in the amygdala. Metabolite levels did not differ between groups, but smokers showed significantly higher glutamine levels at baseline than satiation. Glx levels were negatively associated with pack-years and smoking duration. In summary, this study provides first insights into the neurometabolic profile of the amygdala in smokers with high anatomical specificity. By applying proton magnetic resonance spectroscopy, neurometabolites in smokers during different smoking states and non-smoking controls were quantified reliably. A significant shift in glutamine levels between smoking states was detected, with lower concentrations in satiation than baseline. The negative association between Glx levels and smoking quantity and duration may imply altered glutamate homeostasis with more severe nicotine addiction.

TWIST1 and TSG6 are coordinately regulated and function as potency biomarkers in human MSCs.

Mesenchymal stem/stromal cells (MSCs) have been evaluated in >1500 clinical trials, but outcomes remain suboptimal because of knowledge gaps in quality attributes that confer potency. We show that TWIST1 directly represses TSG6 expression that TWIST1 and TSG6 are inversely correlated across bone marrow-derived MSC (BM-MSC) donor cohorts and predict interdonor differences in their proangiogenic, anti-inflammatory, and immune suppressive activity in vitro and in sterile inflammation and autoimmune type 1 diabetes preclinical models. Transcript profiling of TWIST1HiTSG6Low versus TWISTLowTSG6Hi BM-MSCs revealed previously unidentified roles for TWIST1/TSG6 in regulating cellular oxidative stress and TGF-ß2 in modulating TSG6 expression and anti-inflammatory activity. TWIST1 and TSG6 levels also correlate to donor stature and predict differences in iPSC-derived MSC quality attributes. These results validate TWIST1 and TSG6 as biomarkers that predict interdonor differences in potency across laboratories and assay platforms, thereby providing a means to manufacture MSC products tailored to specific diseases.

Blocking of ebolavirus spread through intercellular connections by an MPER-specific antibody depends on BST2/tetherin.

Ebola virus (EBOV) and Bundibugyo virus (BDBV) belong to the family Filoviridae and cause a severe disease in humans. We previously isolated a large panel of monoclonal antibodies from B cells of human survivors from the 2007 Uganda BDBV outbreak, 16 survivors from the 2014 EBOV outbreak in the Democratic Republic of the Congo, and one survivor from the West African 2013-2016 EBOV epidemic. Here, we demonstrate that EBOV and BDBV are capable of spreading to neighboring cells through intercellular connections in a process that depends upon actin and T cell immunoglobulin and mucin 1 protein. We quantify spread through intercellular connections by immunofluorescence microscopy and flow cytometry. One of the antibodies, BDBV223, specific to the membrane-proximal external region, induces virus accumulation at the plasma membrane. The inhibiting activity of BDBV223 depends on BST2/tetherin.

Sodium and potassium consumption in Jamaica: National estimates and associated factors from the Jamaica Health and Lifestyle Survey 2016-2017.

This study aimed to estimate dietary sodium and potassium consumption among Jamaicans and evaluate associations with sociodemographic and clinical characteristics. A cross-sectional study was conducted using data from the Jamaica Health and Lifestyle Survey 2016-2017. Participants were noninstitutionalized Jamaicans aged ≥15 years. Trained staff collected sociodemographic and health data via interviewer-administered questionnaires and spot urine samples. The Pan American Health Organization formula was used to estimate 24-hour urine sodium and potassium excretion. High sodium level was defined as ≥2000 mg/day, and low potassium levels as <3510 mg/day (World Health Organization criteria). Associations between these outcomes and sociodemographic and clinical characteristics were explored using multivariable ANOVA models using log-transformed 24-hour urine sodium and potassium as outcome variables. Analyses included 1009 participants (368 males, 641 females; mean age 48.5 years). The mean sodium excretion was 3582 mg/day (males 3943 mg/day, females 3245 mg/day, P < .001). The mean potassium excretion was 2052 mg/day (males, 2210 mg/day; females, 1904 mg/day; P = .001). The prevalence of high sodium consumption was 66.6% (males 72.8%, females 60.7%, P < .001) and that of low potassium intake was 88.8% (85.1% males, 92.3% females, P < .001). Sodium consumption was inversely associated with older age, higher education, and low glomerular filtration rate but was directly associated with being male, current smoking, and obesity. Overall, males had higher sodium consumption than women, with the effect being larger among hypertensive men. Women with hypertension had lower sodium consumption than nonhypertensive women; however, hypertensive men had higher sodium consumption than nonhypertensive men. Potassium consumption was higher among men, persons with obesity, and those with high total cholesterol but was lower among men with "more than high school" education compared to men with "less than high school" education. We conclude that most Jamaican adults have diets high in sodium and low in potassium. In this study, sodium consumption was directly associated with male sex, obesity, and current smoking but was inversely associated with older age and higher education. High potassium consumption was associated with obesity and high cholesterol levels. These associations should be further explored in longitudinal studies and population-based strategies should be developed to address these cardiovascular risk factors.

An Experimental Field Trial Investigating the Use of Bacteriophage and Manure Slurry Applications in Beef Cattle Feedlot Pens for Salmonella Mitigation.

Post-harvest Salmonella mitigation techniques are insufficient at addressing Salmonella harbored in cattle lymph nodes, necessitating the exploration of pre-harvest alternatives that reduce Salmonella prior to dissemination to the lymph nodes. A 2 × 2, unbalanced experiment was conducted to determine the effectiveness of pre-harvest treatments applied to the pen surface for Salmonella mitigation in cattle. Treatments included manure slurry intended to mimic pen run-off water (n = 4 pens), a bacteriophage cocktail (n = 4), a combination of both treatments (n = 5), and a control group (n = 5) that received no treatment. Environment samples from 18 feedlot pens and fecal grabs, hide swabs, and subiliac lymph nodes from 178 cattle were collected and selectively enriched for Salmonella, and Salmonella isolates were sequenced. The combination treatment was most effective at reducing Salmonella, and the prevalence was significantly lower compared with the control group for rump swabs on Days 14 and 21. The treatment impact on Salmonella in the lymph nodes could not be determined due to low prevalence. The reduction on cattle hides suggests that bacteriophage or water treatments applied to the feedlot pen surface may reduce Salmonella populations in cattle during the pre-harvest period, resulting in reduced contamination during slaughter and processing.

Intranasal mRNA-LNP vaccination protects hamsters from SARS-CoV-2 infection.

Intranasal vaccination represents a promising approach for preventing disease caused by respiratory pathogens by eliciting a mucosal immune response in the respiratory tract that may act as an early barrier to infection and transmission. This study investigated immunogenicity and protective efficacy of intranasally administered messenger RNA (mRNA)-lipid nanoparticle (LNP) encapsulated vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Syrian golden hamsters. Intranasal mRNA-LNP vaccination systemically induced spike-specific binding [immunoglobulin G (IgG) and IgA] and neutralizing antibodies. Intranasally vaccinated hamsters also had decreased viral loads in the respiratory tract, reduced lung pathology, and prevented weight loss after SARS-CoV-2 challenge. Together, this study demonstrates successful immunogenicity and protection against respiratory viral infection by an intranasally administered mRNA-LNP vaccine.

Effects of Shape and Size on Microplastic Atmospheric Settling Velocity.

Microplastics (MPs) have been found in all terrestrial, marine, and riparian environments, including remote regions. This implies that atmospheric transport is an important pathway when considering MP sources and global budgets. However, limited empirical data exist to aid in effective development and parameterization of MP atmospheric transport models. This study measured the atmospheric settling and horizontal drift velocities of various sizes and shapes of MPs in two specially designed settling columns using a laser Doppler anemometer. The settling velocities were generally lower than modeled values, while shape exerted the most significant influence on the rate of settling. Rather than conforming to well-established, power-law models, each class of MP exhibited a linear but different relationship between MP size and settling velocity, with markedly higher slopes for the spheres and cylinders as compared to the films and fibers. Shape also had a substantial influence on particle drift, with the fibers and films exhibiting the greatest horizontal motion, as suggestive of their changing orientation in response to particle interactions and fluid drag. As a consequence, microplastic particles identified within atmospheric deposition samples collected at a single point may derive from entirely different sources representing a wide range in transport distance.

Multimorbidity patterns and health-related quality of life in Jamaican adults: a cross sectional study exploring potential pathways.

Introduction: Multimorbidity and health-related quality of life (HRQoL) are intimately linked. Multiple chronic conditions may adversely affect physical and mental functioning, while poorer HRQoL may contribute to the worsening course of diseases. Understanding mechanisms through which specific combinations of diseases affect HRQoL outcomes can facilitate identification of factors which are amenable to intervention. Jamaica, a middle-income country with high multimorbidity prevalence, has a health service delivery system dominated by public sector provision via a broad healthcare network. This study aims to examine whether multimorbidity classes differentially impact physical and mental dimensions of HRQoL in Jamaicans and quantify indirect effects on the multimorbidity-HRQoL relationship that are mediated by health system factors pertaining to financial healthcare access and service use. Materials and methods: Latent class analysis (LCA) was used to estimate associations between multimorbidity classes and HRQoL outcomes, using latest available data from the nationally representative Jamaica Health and Lifestyle Survey 2007/2008 (N = 2,551). Multimorbidity measurement was based on self-reported presence/absence of 11 non-communicable diseases (NCDs). HRQoL was measured using the 12-item short-form (SF-12) Health Survey. Mediation analyses guided by the counterfactual approach explored indirect effects of insurance coverage and service use on the multimorbidity-HRQoL relationship. Results: LCA revealed four profiles, including a Relatively Healthy class (52.7%) characterized by little to no morbidity and three multimorbidity classes characterized by specific patterns of NCDs and labelled Metabolic (30.9%), Vascular-Inflammatory (12.2%), and Respiratory (4.2%). Compared to the Relatively Healthy class, Vascular-Inflammatory class membership was associated with lower physical functioning (ß = -5.5; p < 0.001); membership in Vascular-Inflammatory (ß = -1.7; p < 0.05), and Respiratory (ß = -2.5; p < 0.05) classes was associated with lower mental functioning. Significant mediated effects of health service use, on mental functioning, were observed for Vascular-Inflammatory (p < 0.05) and Respiratory (p < 0.05) classes. Conclusion: Specific combinations of diseases differentially impacted HRQoL outcomes in Jamaicans, demonstrating the clinical and epidemiological value of multimorbidity classes for this population, and providing insights that may also be relevant to other settings. To better tailor interventions to support multimorbidity management, additional research is needed to elaborate personal experiences with healthcare and examine how health system factors reinforce or mitigate positive health-seeking behaviours, including timely use of services.

Ebola Virus NP Binding to Host Protein Phosphatase-1 Regulates Capsid Formation.

The Ebola virus (EBOV) transcriptional regulation involves host protein phosphatases PP1 and PP2A, which dephosphorylate the transcriptional cofactor of EBOV polymerase VP30. The 1E7-03 compound, which targets PP1, induces VP30 phosphorylation and inhibits EBOV infection. This study aimed to investigate the role of PP1 in EBOV replication. When EBOV-infected cells were continuously treated with 1E7-03, the NP E619K mutation was selected. This mutation moderately reduced EBOV minigenome transcription, which was restored by the treatment with 1E7-03. Formation of EBOV capsids, when NP was co-expressed with VP24 and VP35, was impaired with NPE 619K. Treatment with 1E7-03 restored capsid formation by NP E619K mutation, but inhibited capsids formed by WT NP. The dimerization of NP E619K, tested in a split NanoBiT assay, was significantly decreased (~ 15-fold) compared to WT NP. NP E619K bound more efficiently to PP1 (~ 3-fold) but not B56 subunit of PP2A or VP30. Cross-linking and co-immunoprecipitation experiments showed fewer monomers and dimers for NP E619K which were increased with 1E7-03 treatment. NP E619K showed increased co-localization with PP1α compared to WT NP. Mutations of potential PP1 binding sites and NP deletions disrupted its interaction with PP1. Collectively, our findings suggest that PP1 binding to the NP regulates NP dimerization and capsid formation, and that NP E619K mutation, which has the enhanced PP1 binding, disrupts these processes. Our results point to a new role for PP1 in EBOV replication in which NP binding to PP1 may facilitate viral transcription by delaying capsid formation and EBOV replication.

Annexin A2 modulates phospholipid membrane composition upstream of Arp2 to control angiogenic sprout initiation.

The intersection of protein and lipid biology is of growing importance for understanding how cells address structural challenges during adhesion and migration. While protein complexes engaged with the cytoskeleton play a vital role, support from the phospholipid membrane is crucial for directing localization and assembly of key protein complexes. During angiogenesis, dramatic cellular remodeling is necessary for endothelial cells to shift from a stable monolayer to invasive structures. However, the molecular dynamics between lipids and proteins during endothelial invasion are not defined. Here, we utilized cell culture, immunofluorescence, and lipidomic analyses to identify a novel role for the membrane binding protein Annexin A2 (ANXA2) in modulating the composition of specific membrane lipids necessary for cortical F-actin organization and adherens junction stabilization. In the absence of ANXA2, there is disorganized cortical F-actin, reduced junctional Arp2, excess sprout initiation, and ultimately failed sprout maturation. Furthermore, we observed reduced filipin III labeling of membrane cholesterol in cells with reduced ANXA2, suggesting there is an alteration in phospholipid membrane dynamics. Lipidomic analyses revealed that 42 lipid species were altered with loss of ANXA2, including an accumulation of phosphatidylcholine (16:0_16:0). We found that supplementation of phosphatidylcholine (16:0_16:0) in wild-type endothelial cells mimicked the ANXA2 knock-down phenotype, indicating that ANXA2 regulated the phospholipid membrane upstream of Arp2 recruitment and organization of cortical F-actin. Altogether, these data indicate a novel role for ANXA2 in coordinating events at endothelial junctions needed to initiate sprouting and show that proper lipid modulation is a critical component of these events.

Factors That Affect Opioid Quality Improvement Initiatives in Primary Care: Insights from Ten Health Systems.

OBJECTIVE: To improve patient safety and pain management, the Centers for Disease Control and Prevention (CDC) released the Guideline for Prescribing Opioids for Chronic Pain (CDC Guideline). Recognizing that issuing a guideline alone is insufficient for transforming practice, CDC supported an Opioid Quality Improvement (QI) Collaborative, consisting of 10 health care systems that represented more than 120 practices across the United States. The research team identified factors related to implementation success using domains described by the integrated Promoting Action on Research Implementation in Health Services (iPARIHS) implementation science framework. METHODS: Data from interviews, notes from check-in calls, and documents provided by systems were used. The researchers collected data throughout the project through interviews, meeting notes, and documents. RESULTS: The iPARIHS framework was used to identify factors that affected implementation related to the context, innovation (implementing recommendations from the CDC Guideline), recipient (clinicians), and facilitation (QI team). Contextual characteristics were at the clinic, health system, and broader external context, including staffing and leadership support, previous QI experience, and state laws. Characteristics of the innovation were its adaptability and challenges operationalizing the measures. Recipient characteristics included belief in the importance of the innovation but challenges engaging in the initiative. Finally, facilitation characteristics driving differential outcomes included staffing and available time of the QI team, the ability to make changes, and experience with QI. CONCLUSION: As health care systems continue to implement the CDC Guideline, these insights can advance successful implementation efforts by describing common implementation challenges and identifying strategies to prepare for and overcome them.

[Is it a sexually transmitted disease?] / Is dit een soa?

STD-associated questions and symptoms are submitted frequently to general practitioners and STD outpatient-clinics. In this teaching article we address 10 important clinical questions regarding epidemiology, risk assessment, testing policy, diagnostics and prevention. STD's form a separate category of infectious diseases because of the role of sexuality. Good communication about sexual behavior is indispensable for an adequate diagnosis. We discuss the recognition of extragenital manifestations of STD, which requires alertness. Estimating the STD-risk based on sexual behavior is essential for testing policy. Persons at high risk are tested for the big five. In other cases testing is based on symptoms and complaints. HIV and syphilis are serious std's. Early detection followed by treatment is important in preventing health damage and preventing further spread. Hiv-indicator-conditions are useful alarm-signs for this purpose. PrEP can help not to acquire hiv and increases sexual health. It can be prescribed by gp's and public health clinicians. But condom-use remains crucial in prevention.

Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins.

OBJECTIVE: To (1) describe exposure history, clinical signs, treatment, and diagnostic findings in 4 dogs following ingestion of tamarinds, and in 2 dogs following ingestion of cream of tartar, and (2) discuss tartaric acid, the common denominator, as the proposed toxic principle in tamarinds and grapes. SERIES SUMMARY: Reports in which dogs developed acute kidney injury following ingestion of cream of tartar or tamarinds were identified from the ASPCA Animal Poison Control Center electronic database. In these cases, decontamination was not performed, and treatments were delayed. Despite IV fluids and symptomatic and supportive care, 2 of the dogs became anuric and 1 became oliguric. Four dogs were euthanized, and the outcome is unknown for 2 of the dogs. Necropsies were performed on 3 of the dogs. Clinical signs, laboratory findings, and histopathologic lesions were similar to those reported in grape and raisin toxicosis. NEW OR UNIQUE INFORMATION PROVIDED: Acute kidney injury may develop following ingestion of cream of tartar or tamarinds in dogs. Connecting these reports with findings in grape and raisin toxicosis and the sensitivity to tartaric acid in dogs, tartaric acid is identified as the likely toxic component in grapes and tamarinds.

Patient expectations and preferences for community-based hypertension classes with implications for action.

BACKGROUND: Uncontrolled hypertension disproportionately affects Black men. Patient engagement with health promotion and health behavior programs for hypertension control is low. We held evidence-based hypertension classes at a Federally Qualified Health Center. AIMS: The aim of this project was to elicit patient preferences and expectations for community-based hypertension classes. METHODS: Group hypertension classes were held at a Federally Qualified Health Center. The priority population was Black men with hypertension. Semi-structured interviews were conducted with the group class attendees. Two independent coders performed content analysis using field notes from the interviews. RESULTS: Seven group class attendees were interviewed. Six interviewees were Black males, one was a Black female, and the mean age was 65.7 years. Content analysis of the interview field notes revealed five content areas: (1) Recommendation of Group Classes to a Friend, (2) Expectations for the Group Classes, (3) Reasons for Continued Attendance, (4) Lifestyle Changes and Adopting the Group Class Lessons, and (5) Feedback and Recommendations to Improve Group Classes. Findings suggest that creating a cultural context in which open, transparent discussion of blood pressure occur can be achieved. Thus, regarding acceptability, classes fulfilled and often exceeded the attendees' expectations and needs. LINKING EVIDENCE TO ACTION: Our findings suggest that community-based group classes are a viable intervention to contribute toward addressing the disparity of hypertension control among Black men. When designing peer-group interventions, taking patient preferences and expectations into account increases the effectiveness of these interventions. The qualitative narrative provided in this paper contributes to the development of similar community-based group classes for the management of severe hypertension.

COVID-19 brings a new urgency for advance care planning: Implications of death education.

The U.S. has the highest number of coronavirus disease (COVID-19) cases and deaths of any nation. Deaths due to COVID-19, especially among older adults and people of color, have created an urgency for advanced care planning (ACP). Despite benefits of ACP, only one-third of U.S. adults have completed advance directives, in part due to a lack of death education. We recommend four actions to increase death education and ACP completion: (1) integrate death education into teacher preparation programs, (2) incorporate death education in undergraduate curricula, (3) provide better education in death and dying to future health professionals, and (4) educate the public.

The COVID-19 pandemic has changed dying and grief: Will there be a surge of complicated grief?

Worldwide, more than 3 million people have died from COVID-19. Each decedent represents a person who was loved, will be missed, and whose death elicited grief. COVID-19 has changed the way we die and grieve. Many people have died without family members and friends present and many of the bereft have grieved and mourned alone. Individuals and communities have experienced multiple losses within a short time while suffering from concomitant stress, anxiety, and depression. More deaths and more grief will continue in the foreseeable future. Preventive education is needed to prepare for and manage the likely increase in complicated grief.

Antibody Responses to SARS-CoV-2 Following an Outbreak Among Marine Recruits With Asymptomatic or Mild Infection.

We investigated serological responses following a SARS-CoV-2 outbreak in spring 2020 on a US Marine recruit training base. 147 participants that were isolated during an outbreak of respiratory illness were enrolled in this study, with visits approximately 6 and 10 weeks post-outbreak (PO). This cohort is comprised of young healthy adults, ages 18-26, with a high rate of asymptomatic infection or mild symptoms, and therefore differs from previously reported longitudinal studies on humoral responses to SARS-CoV-2, which often focus on more diverse age populations and worse clinical presentation. 80.9% (119/147) of the participants presented with circulating IgG antibodies against SARS-CoV-2 spike (S) receptor-binding domain (RBD) at 6 weeks PO, of whom 97.3% (111/114) remained positive, with significantly decreased levels, at 10 weeks PO. Neutralizing activity was detected in all sera from SARS-CoV-2 IgG positive participants tested (n=38) at 6 and 10 weeks PO, without significant loss between time points. IgG and IgA antibodies against SARS-CoV-2 RBD, S1, S2, and the nucleocapsid (N) protein, as well neutralization activity, were generally comparable between those participants that had asymptomatic infection or mild disease. A multiplex assay including S proteins from SARS-CoV-2 and related zoonotic and human endemic betacoronaviruses revealed a positive correlation for polyclonal cross-reactivity to S after SARS-CoV-2 infection. Overall, young adults that experienced asymptomatic or mild SARS-CoV-2 infection developed comparable humoral responses, with no decrease in neutralizing activity at least up to 10 weeks after infection.