Is the A-1 Pigment in Photosystem I Part of P700? A (P700+-P700) FTIR Difference Spectroscopy Study of A-1 Mutants.

The involvement of the second pair of chlorophylls, termed A-1A and A-1B, in light-induced electron transfer in photosystem I (PSI) is currently debated. Asparagines at PsaA600 and PsaB582 are involved in coordinating the A-1B and A-1A pigments, respectively. Here we have mutated these asparagine residues to methionine in two single mutants and a double mutant in PSI from Synechocystis sp. PCC 6803, which we term NA600M, NB582M, and NA600M/NB582M mutants. (P700+-P700) FTIR difference spectra (DS) at 293 K were obtained for the wild-type and the three mutant PSI samples. The wild-type and mutant FTIR DS differ considerably. This difference indicates that the observed changes in the (P700+-P700) FTIR DS cannot be due to only the PA and PB pigments of P700. Comparison of the wild-type and mutant FTIR DS allows the assignment of different features to both A-1 pigments in the FTIR DS for wild-type PSI and assesses how these features shift upon cation formation and upon mutation. While the exact role the A-1 pigments play in the species we call P700 is unclear, we demonstrate that the vibrational modes of the A-1A and A-1B pigments are modified upon P700+ formation. Previously, we showed that the A-1 pigments contribute to P700 in green algae. In this manuscript, we demonstrate that this is also the case in cyanobacterial PSI. The nature of the mutation-induced changes in algal and cyanobacterial PSI is similar and can be considered within the same framework, suggesting a universality in the nature of P700 in different photosynthetic organisms.

Alpha-Gal IgE Prevalence Patterns in the United States: An Investigation of 3,000 Military Recruits.

BACKGROUND: IgE to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal) is an important cause of allergic reactions to mammalian meat. The "alpha-gal syndrome" is strongly associated with a preceding history of tick bites and in the United States is most commonly reported in parts of the southeast, but there has been limited investigation into national alpha-gal sensitization patterns and the relevance of other risk factors. OBJECTIVE: To systematically investigate alpha-gal IgE prevalence, regional patterns, and risk factors. METHODS: Alpha-gal IgE was measured by ImmunoCAP in biobanked serum samples collected from 3000 service members who presented for intake to 1 of 10 military bases in the central/eastern United States. Alpha-gal IgE sensitization (cutoff 0.1 international units/mL) was related to home of record at enlistment. RESULTS: Of the cohort, 2456 (81.9%) subjects were male, median age was 19 years (interquartile range: 18-22 years), and alpha-gal IgE was detected in 179 (6.0%). Home of record spanned all 50 states, with a median of 36 recruits per state (range: 3-261). The highest prevalence rates were in Arkansas (39%), Oklahoma (35%), and Missouri (29%), with several other southeastern states >10%. Granular mapping revealed sensitization patterns that closely mimicked county-level Amblyomma americanum reports and Ehrlichia chaffeensis infections. Sensitization was associated with male sex, rural residence, and White race in univariate and multivariable models. CONCLUSIONS: In this systematic survey, the prevalence of alpha-gal IgE among incoming military personnel was 6.0%. There were significant regional differences, with an overall pattern consistent with the known range of the lone star tick (A. americanum) and highest frequency in an area including Arkansas, Oklahoma, and Missouri.

Effect of Cardiopulmonary Bypass on SARS-CoV-2 Vaccination Antibody Levels.

Background Adults undergoing heart surgery are particularly vulnerable to respiratory complications, including COVID-19. Immunization can significantly reduce this risk; however, the effect of cardiopulmonary bypass (CPB) on immunization status is unknown. We sought to evaluate the effect of CPB on COVID-19 vaccination antibody concentration after cardiac surgery. Methods and Results This prospective observational clinical trial evaluated adult participants undergoing cardiac surgery requiring CPB at a single institution. All participants received a full primary COVID-19 vaccination series before CPB. SARS-CoV-2 spike protein-specific antibody concentrations were measured before CPB (pre-CPB measurement), 24 hours following CPB (postoperative day 1 measurement), and approximately 1 month following their procedure. Relationships between demographic or surgical variables and change in antibody concentration were assessed via linear regression. A total of 77 participants were enrolled in the study and underwent surgery. Among all participants, mean antibody concentration was significantly decreased on postoperative day 1, relative to pre-CPB levels (-2091 AU/mL, P<0.001). Antibody concentration increased between postoperative day 1and 1 month post CPB measurement (2465 AU/mL, P=0.015). Importantly, no significant difference was observed between pre-CPB and 1 month post CPB concentrations (P=0.983). Two participants (2.63%) developed symptomatic COVID-19 pneumonia postoperatively; 1 case of postoperative COVID-19 pneumonia resulted in mortality (1.3%). Conclusions COVID-19 vaccine antibody concentrations were significantly reduced in the short-term following CPB but returned to pre-CPB levels within 1 month. One case of postoperative COVID 19 pneumonia-specific mortality was observed. These findings suggest the need for heightened precautions in the perioperative period for cardiac surgery patients.

Myocarditis and pericarditis recovery following smallpox vaccine 2002-2016: A comparative observational cohort study in the military health system.

OBJECTIVES: (1) Characterize the initial clinical characteristics and long-term outcomes of smallpox vaccine-associated hypersensitivity myocarditis and pericarditis (MP) in United States service members. (2) Describe the process of case identification and adjudication using the 2003 CDC nationally defined myocarditis/pericarditis epidemiologic case definitions to include consideration of case-specific diversity and evolving evidence. BACKGROUND: Between 2002 and 2016, 2.546 million service members received a smallpox Vaccinia vaccine. Acute MP is associated with vaccinia, but the long-term outcomes have not been studied. METHODS: Records of vaccinia-associated MP reported to the Vaccine Adverse Event Reporting System by vaccination date were adjudicated using the 2003 MP epidemiologic case definitions for inclusion in a retrospective observational cohort study. Descriptive statistics of clinical characteristics, presentation, cardiac complications, and time course of clinical and cardiac recovery were calculated with comparisons by gender, diagnosis and time to recovery. RESULTS: Out of over 5000 adverse event reports, 348 MP cases who survived the acute illness, including 276 myocarditis (99.6% probable/confirmed) and 72 pericarditis (29.2% probable/confirmed), were adjudicated for inclusion in the long-term follow-up. Demographics included a median age of 24 years (IQR 21,30) and male predominance (96%). Compared to background military population, the myocarditis and pericarditis cohort had a higher percentage of white males by 8.2% (95% CI: 5.6, 10.0) and age <40 years by 4.2% (95% CI: 1.7,5.8). Long-term follow-up documented full recovery in 267/306 (87.3%) with 74.9% recovered in less than a year (median ~3 months). Among patients with myocarditis, the percentage who had a delayed time to recovery at time of last follow-up was 12.8% (95% CI: 2.1,24.7) higher in those with an acute left ventricular ejection fraction (EF) of ≤50% and 13.5% (95% CI: 2.4,25.7) higher in those with hypokinesis. Patient complications included 6 ventricular arrhythmias (2 received implanted defibrillators) and 14 with atrial arrhythmias (2 received radiofrequency ablation). Three of 6 patients (50%) diagnosed with cardiomyopathy had clinical recovery at their last follow-up date. CONCLUSIONS: Hypersensitivity myocarditis/pericarditis following the smallpox vaccine is associated with full clinical and functional ventricular recovery in over 87% of cases (74.9% <1 year). A minority of MP cases experienced prolonged or incomplete recovery beyond 1 year.

Enhanced SARS-CoV-2 IgG durability following COVID-19 mRNA booster vaccination and comparison of BNT162b2 with mRNA-1273.

BACKGROUND: BNT162b2 (Pfizer/BioNTech, Comirnaty) and mRNA-1273 (Moderna, Spikevax) are messenger RNA (mRNA) vaccines that elicit antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (S-RBD) and have been approved by the US Food and Drug Administration to combat the coronavirus disease 2019 (COVID-19) pandemic. Because vaccine efficacy and antibody levels waned over time after the 2-shot primary series, the US Food and Drug Administration authorized a booster (third) dose for both mRNA vaccines to adults in the fall of 2021. OBJECTIVE: To evaluate the magnitude and durability of S-RBD immunoglobulin (Ig)G after the booster mRNA vaccine dose in comparison to the primary series. We also compared S-RBD IgG levels after BNT162b2 and mRNA-1273 boosters and explored effects of age and prior infection. METHODS: Surrounding receipt of the second and third homologous mRNA vaccine doses, adults in an employee-based cohort provided serum and completed questionnaires, including information about previous COVID-19 infection. The IgG to S-RBD was measured using an ImmunoCAP-based system. A subset of samples were assayed for IgG to SARS-CoV-2 nucleocapsid by commercial assay. RESULTS: There were 228 subjects who had samples collected between 7 and 150 days after their primary series vaccine and 117 subjects who had samples collected in the same time frame after their boost. Antibody levels from 7 to 31 days after the primary series and booster were similar, but S-RBD IgG was more durable over time after the boost, regardless of prior infection status. In addition, mRNA-1273 post-boost antibody levels exceeded BNT162b2 out to 5 months. CONCLUSION: The COVID-19 mRNA vaccine boosters increase antibody durability, suggesting enhanced long-term clinical protection from SARS-CoV-2 infection compared with the 2-shot regimen.

Trajectory of IgG to SARS-CoV-2 After Vaccination With BNT162b2 or mRNA-1273 in an Employee Cohort and Comparison With Natural Infection.

Three COVID-19 vaccines have received FDA-authorization and are in use in the United States, but there is limited head-to-head data on the durability of the immune response elicited by these vaccines. Using a quantitative assay we studied binding IgG antibodies elicited by BNT162b2, mRNA-1273 or Ad26.COV2.S in an employee cohort over a span out to 10 months. Age and sex were explored as response modifiers. Of 234 subjects in the vaccine cohort, 114 received BNT162b2, 114 received mRNA-1273 and six received Ad26.COV2.S. IgG levels measured between seven to 20 days after the second vaccination were similar in recipients of BNT162b2 and mRNA-127 and were ~50-fold higher than in recipients of Ad26.COV2.S. However, by day 21 and at later time points IgG levels elicited by BNT162b2 were lower than mRNA-1273. Accordingly, the IgG decay curve was steeper for BNT162b2 than mRNA-1273. Age was a significant modifier of IgG levels in recipients of BNT162b2, but not mRNA-1273. After six months, IgG levels elicited by BNT162b2, but not mRNA-1273, were lower than IgG levels in patients who had been hospitalized with COVID-19 six months earlier. Similar findings were observed when comparing vaccine-elicited antibodies with steady-state IgG targeting seasonal human coronaviruses. Differential IgG decay could contribute to differences observed in clinical protection over time between BNT162b2 and mRNA-1273.

SARS-CoV-2 Vaccines: Where Are We Now?

The best and safest way to control the coronavirus disease 2019 (COVID-19) pandemic is by using vaccination to generate widespread immunity. The urgent need to develop safe and effective COVID-19 vaccines was met with unprecedented speed and action from the global community. There are now 289 vaccines in the development pipeline. More remarkably, there are 20 publicly available vaccines, and more than 3.3 billion doses of COVID-19 vaccines have been administered across 180 countries. This is just the beginning of our fight against the pandemic. Even at the current vaccination rate, it could take years to vaccinate the world's population; many high-income countries are focusing on their needs, whereas the poorer nations are waiting for vaccines. There is still much that we do not understand about immunity to this new disease, and we will have to contend with the emerging variants. In this commentary, we describe the current status of COVID-19 vaccine development and provide insights into how the development and approvals happened so quickly. We discuss the clinical trial data that led to rapid emergency use authorization and the many challenges of global rollout. We also comment on some of the key unanswered questions and future directions for COVID-19 vaccine development and deployment.

Insufficient Anthrax Lethal Toxin Neutralization Is Associated with Antibody Subclass and Domain Specificity in the Plasma of Anthrax-Vaccinated Individuals.

Anthrax vaccine adsorbed (AVA) is a significant line of defense against bioterrorist attack from Bacillus anthracis spores. However, in a subset of individuals, this vaccine may produce a suboptimal quantity of anti-protective antigen (PA), antibodies that are poorly neutralizing, and/or antibody titers that wane over time, necessitating annual boosters. To study individuals with such poor responses, we examine the properties of anti-PA in a subset of vaccinated individuals that make significant quantities of antibody but are still unable to neutralize toxin. In this cohort, characterized by poorly neutralizing antibody, we find that increased IgG4 to IgG1 subclass ratios, low antibody avidity, and insufficient antibody targeting domain 4 associate with improper neutralization. Thus, future vaccines and vaccination schedules should be formulated to improve these deficiencies.

Health disparities in allergic and immunologic conditions in racial and ethnic underserved populations: A Work Group Report of the AAAAI Committee on the Underserved.

Health disparities are health differences linked with economic, social, and environmental disadvantage. They adversely affect groups that have systematically experienced greater social or economic obstacles to health. Renewed efforts are needed to reduced health disparities in the United States, highlighted by the disparate impact on racial minorities during the coronavirus pandemic. Institutional or systemic patterns of racism are promoted and legitimated through accepted societal standards, and organizational processes within the field of medicine, and contribute to health disparities. Herein, we review current evidence regarding health disparities in allergic rhinitis, asthma, atopic dermatitis, food allergy, drug allergy, and primary immune deficiency disease in racial and ethnic underserved populations. Best practices to address these disparities involve addressing social determinants of health and adopting policies to improve access to specialty care and treatment for the underserved through telemedicine and community partnerships, cross-cultural provider training to reduce implicit bias, inclusion of underserved patients in research, implementation of culturally competent patient education, and recruitment and training of health care providers from underserved communities. Addressing health disparities requires a multilevel approach involving patients, health providers, local agencies, professional societies, and national governmental agencies.

A multi-niche microvascularized human bone marrow (hBM) on-a-chip elucidates key roles of the endosteal niche in hBM physiology.

The human bone marrow (hBM) is a complex organ critical for hematopoietic and immune homeostasis, and where many cancers metastasize. Understanding the fundamental biology of the hBM in health and diseases remain difficult due to complexity of studying or manipulating the BM in humans. Accurate biomaterial-based in vitro models of the hBM microenvironment are critical to further our understanding of the BM-niche and advancing new clinical interventions. Here we report a unique, 96-well format, microfluidic hBM-on-a-chip that incorporates the endosteal, central marrow, and perivascular niches of the human BM. Osteogenic differentiation of donor human mesenchymal stromal cells (MSCs) produced robust mineralization on the bottom surface ("bone-like endosteal layer") of the device, and subsequent seeding of human endothelial cells and MSCs in a fibrin-collagen hydrogel network ("central marrow") on the top created an interconnected 3D microvascular network ("perivascular niche"). The 96-well format allows eight independent "chips" to be studied in one plate, thereby increasing throughput and reproducibility. We show that this complex, multi-niche microtissue accurately mimics hBM composition and microphysiology, while providing key insights on hematopoietic progenitor dynamics. Presence of the endosteal niche decreased the proliferation and increased maintenance of CD34+ hematopoietic stem cells (HSCs). Upon exposure to radiation, HSCs in the hBM-chips containing endosteal niches were less frequently apoptotic, suggesting a potentially radio-protective role of the osteoblast surface. Our methods and results provide a broad platform for creating complex, multi-niche, high-throughput microphysiological (MPS) systems. Specifically, this hBM-on-a-chip opens new opportunities in human bone marrow research and therapeutics development, and can be used to better understand normal and impaired hematopoiesis, and various hBM pathologies, including cancer and BM failures.

A 96-well format microvascularized human lung-on-a-chip platform for microphysiological modeling of fibrotic diseases.

Development of organoids and microfluidic on-chip models has enabled studies of organ-level disease pathophysiologies in vitro. However, current lung-on-a-chip platforms are primarily monolayer epithelial-endothelial co-cultures, separated by a thin membrane, lacking microvasculature-networks or interstitial-fibroblasts. Here we report the design, microfabrication, and characterization of a unique microphysiological on-chip device that recapitulates the human lung interstitium-airway interface through a 3D vascular network, and normal or diseased fibroblasts encapsulated within a fibrin-collagen hydrogel underneath an airlifted airway epithelium. By incorporating fibroblasts from donors with idiopathic pulmonary fibrosis (IPF), or healthy-donor fibroblasts treated with TGF-ß1, we successfully created a fibrotic, alpha smooth muscle actin (αSMA)-positive disease phenotype which led to fibrosis-like transformation in club cells and ciliated cells in the airway. Using this device platform, we further modeled the cystic fibrosis (CF) epithelium and recruitment of neutrophils to the vascular networks. Our results suggest that this microphysiological model of the human lung could enable more pathophysiologically relevant studies of complex pulmonary diseases.

Moving Beyond Accidental Leadership: A Graduate Medical Education Leadership Curriculum Needs Assessment.

BACKGROUND: Despite calls for greater physician leadership, few medical schools, and graduate medical education programs provide explicit training on the knowledge, skills, and attitudes necessary to be an effective physician leader. Rather, most leaders develop through what has been labeled "accidental leadership." A survey was conducted at Walter Reed to define the current status of leadership development and determine what learners and faculty perceived as key components of a leadership curriculum. METHODS: A branching survey was developed for residents and faculty to assess the perceived need for a graduate medical education leadership curriculum. The questionnaire was designed using survey best practices and established validity through subject matter expert reviews and cognitive interviewing. The survey instrument assessed the presence of a current leadership curriculum being conducted by each department, the perceived need for a leadership curriculum for physician leaders, the topics that needed to be included, and the format and timing of the curriculum. Administered using an online/web-based survey format, all 2,041 house staff and educators at Walter Reed were invited to participate in the survey. Descriptive statistics were conducted using SPSS (version 22). RESULTS: The survey response rate was 20.6% (421/2,041). Only 17% (63/266) of respondents stated that their program had a formal leadership curriculum. Trainees ranked their current leadership abilities as slightly better than moderately effective (3.22 on a 5-point effectiveness scale). Trainee and faculty availability were ranked as the most likely barrier to implementation. Topics considered significantly important (on a 5-point effectiveness scale) were conflict resolution (4.1), how to motivate a subordinate (4.0), and how to implement change (4.0). Respondents ranked the following strategies highest in perceived effectiveness on a 5-point scale (with 3 representing moderate effectiveness): leadership case studies (3.3) and small group exercises (3.2). Online power points were reported as only slightly effective (1.9). Free text comments suggest that incorporating current duties, a mentoring and coaching component, and project based would be valuable to the curriculum. DISCUSSION: Few training programs at Walter Reed have a dedicated leadership curriculum. The survey data provide important information for programs considering implementing a leadership development curriculum in terms of content and delivery.

Unique Inflammatory Mediators and Specific IgE Levels Distinguish Local from Systemic Reactions after Anthrax Vaccine Adsorbed Vaccination.

Although the U.S. National Academy of Sciences concluded that anthrax vaccine adsorbed (AVA) has an adverse event (AE) profile similar to those of other adult vaccines, 30 to 70% of queried AVA vaccinees report AEs. AEs appear to be correlated with certain demographic factors, but the underlying immunologic pathways are poorly understood. We evaluated a cohort of 2,421 AVA vaccinees and found 153 (6.3%) reported an AE. Females were more likely to experience AEs (odds ratio [OR] = 6.0 [95% confidence interval {CI} = 4.2 to 8.7]; P < 0.0001). Individuals 18 to 29 years of age were less likely to report an AE than individuals aged 30 years or older (OR = 0.31 [95% CI = 0.22 to 0.43]; P < 0.0001). No significant effects were observed for African, European, Hispanic, American Indian, or Asian ancestry after correcting for age and sex. Additionally, 103 AEs were large local reactions (LLRs), whereas 53 AEs were systemic reactions (SRs). In a subset of our cohort vaccinated 2 to 12 months prior to plasma sample collection (n = 75), individuals with LLRs (n = 33) had higher protective-antigen (PA)-specific IgE levels than matched, unaffected vaccinated individuals (n = 50; P < 0.01). Anti-PA IgE was not associated with total plasma IgE, hepatitis B-specific IgE, or anti-PA IgG in individuals who reported an AE or in matched, unaffected AVA-vaccinated individuals. IP-10 was also elevated in sera of individuals who developed LLRs (P < 0.05). Individuals reporting SRs had higher levels of systemic inflammation as measured from C-reactive protein (P < 0.01). Thus, LLRs and SRs are mediated by distinct pathways. LLRs are associated with a vaccine-specific IgE response and IP-10, whereas SRs demonstrate increased systemic inflammation without a skewed cytokine profile.