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COVID-19 booster dose vaccination has been crucial in ensuring protection against COVID-19 including recently predominant Omicron variants. Because vaccines against newer SARS-CoV- 2 variants are likely to be recommended in future, it will be valuable to understand past booster dose uptake among different demographic groups. Using U.S. vaccination data, this study examined intervals between primary series completion and receipt of first booster dose (monovalent or bivalent) during August 2021 - October 2022 among persons ≥12 years of age who had completed a COVID-19 vaccine primary series by October 2021. Sub-populations who were late booster recipients (received a booster dose ≥12 months after the primary series) or received no booster dose included persons <35 years old, Johnson & Johnson/Janssen vaccine primary dose recipients, persons in certain racial and ethnic groups, and persons living in rural and more socially vulnerable areas, and in the South region of the United States; these groups may benefit the most from public health outreach efforts to achieve timely COVID-19 vaccination completion in future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

To help achieve the initial goal of providing universal COVID-19 vaccine access to approximately 258 million adults in 62 US jurisdictions, the federal government launched the Federal Retail Pharmacy Program (FRPP) on February 11, 2021. We describe FRPP's collaboration among the federal government, US jurisdictions, federal entity partners, and 21 national chain and independent pharmacy networks to provide large-scale access to COVID-19 vaccines, particularly in communities disproportionately affected by COVID-19 (eg, people aged ≥65 years, people from racial and ethnic minority groups). FRPP initially provided 10 000 vaccination sites for people to access COVID-19 vaccines, which was increased to >35 000 vaccination sites by May 2021 and sustained through January 31, 2022. From February 11, 2021, through January 31, 2022, FRPP vaccination sites received 293 million doses and administered 219 million doses, representing 45% of all COVID-19 immunizations provided nationwide (38% of all first doses, 72% of all booster doses). This unprecedented public-private partnership allowed the federal government to rapidly adapt and scale up an equitable vaccination program to reach adults, later expanding access to vaccine-eligible children, during the COVID-19 pandemic. As the largest federal COVID-19 vaccination program, FRPP exemplifies how public-private partnerships can expand access to immunizations during a public health emergency. Pharmacies can help meet critical national public health goals by serving as convenient access points for sustained health services. Lessons learned from this effort-including the importance of strong coordination and communication, efficient reporting systems and data quality, and increasing access to and demand for vaccine, among others-may help improve future immunization programs and support health system resiliency, emphasizing community-level access and health equity during public health emergencies., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Antigen-specific class-switched antibodies are detected at the same time or even before IgM in serum of non-vaccinated individuals infected with SARS-CoV-2. These derive from the first wave of plasmablasts formed. Hence, the phenotype and specificity of plasmablasts can reveal information about early B-cell activation. Here we have analyzed B cells and plasmablasts circulating in blood of COVID-19 patients not previously exposed to SARS-CoV-2 during and after disease. We find that during infection with the original Wuhan strain, plasmablasts in blood produce IgA1, IgG1, and IgM, and that most express CCR10 and integrin β1, only some integrin β7, while the majority lack CCR9. Plasmablast-secreted antibodies are reactive to the spike (S) and nucleocapsid (N) proteins of the Wuhan strain as well as later variants of concern, but also bind S proteins from endemic and non-circulating betacoronaviruses. In contrast, after recovery, antibodies produced from memory B cells target variants of SARS-CoV-2 and SARS-CoV-1 but compared to previously non-infected individuals do not show increased binding to endemic coronaviruses. This suggests that the early antibody response to a large extent stems from pre-existing cross-reactive class-switched memory B cells, and that although newly formed memory cells target the novel SARS-CoV-2 virus the numbers of broadly cross-reactive memory B cells do not increase extensively. The observations give insight into the role of pre-existing memory B cells in early antibody responses to novel pathogens and may explain why class-switched antibodies are detected early in the serum of COVID-19 patients., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Immunology.)

Introduction: In 2021, HHS Office of Minority Health and CDC developed a composite measure of social vulnerability called the Minority Health Social Vulnerability Index (MHSVI) to assess the needs of communities most vulnerable to COVID-19. The MHSVI extends the CDC Social Vulnerability Index with two new themes on healthcare access and medical vulnerability. This analysis examines COVID-19 vaccination coverage by social vulnerability using the MHSVI., Methods: County-level COVID-19 vaccine administration data among persons aged ≥18 years reported to CDC from 12/14/20 to 01/31/22 were analyzed. U.S. counties from 50 states and DC were categorized into tertiles of vulnerability (low, moderate, and high) for the composite MHSVI measure and each of the 34 indicators. Vaccination coverage (≥1 dose, primary series completion, and receipt of a booster dose) was calculated by tertiles for the composite MHSVI measure and each indicator., Results: Counties with lower per capita income, higher proportion of individuals with no high school diploma, living below poverty, ≥65 years of age, with a disability, and in mobile homes had lower vaccination uptake. However, counties with larger proportions of racial/ethnic minorities and individuals speaking English less than "very well" had higher coverage. Counties with fewer primary care physicians and greater medical vulnerabilities had lower ≥ 1 dose vaccination coverage. Furthermore, counties of high vulnerability had lower primary series completion and receipt of a booster dose. There were no clear patterns in COVID-19 vaccination coverage by tertiles for the composite measure., Conclusion: Results from the new components in the MHSVI identify needs to prioritize persons in counties with greater medical vulnerabilities and limited access to health care, who are at greater risk for adverse COVID-19 outcomes. Findings suggest that using a composite measure to characterize social vulnerability might mask disparities in COVID-19 vaccination uptake that would have otherwise been observed using specific indicators., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Although severe COVID-19 illness and hospitalization are more common among older adults, children can also be affected (1). More than 3 million cases of COVID-19 had been reported among infants and children aged <5 years (children) as of December 2, 2022 (2). One in four children hospitalized with COVID-19 required intensive care; 21.2% of cases of COVID-19-related multisystem inflammatory syndrome in children (MIS-C) occurred among children aged 1-4 years, and 3.2% of MIS-C cases occurred among infants aged <1 year (1,3). On June 17, 2022, the Food and Drug Administration issued an Emergency Use Authorization (EUA) of the Moderna COVID-19 vaccine for children aged 6 months-5 years and the Pfizer-BioNTech COVID-19 vaccine for children aged 6 months-4 years. To assess COVID-19 vaccination coverage among children aged 6 months-4 years in the United States, coverage with ≥1 dose* and completion of the 2-dose or 3-dose primary vaccination series † were assessed using vaccine administration data for the 50 U.S. states and District of Columbia submitted from June 20 (after COVID-19 vaccine was first authorized for this age group) through December 31, 2022. As of December 31, 2022, ≥1-dose COVID-19 vaccination coverage among children aged 6 months-4 years was 10.1% and was 5.1% for series completion. Coverage with ≥1 dose varied by jurisdiction (range = 2.1% [Mississippi] to 36.1% [District of Columbia]) as did coverage with a completed series (range = 0.7% [Mississippi] to 21.4% [District of Columbia]), respectively. By age group, 9.7 % of children aged 6-23 months and 10.2% of children aged 2-4 years received ≥1 dose; 4.5% of children aged 6-23 months and 5.4% of children aged 2-4 years completed the vaccination series. Among children aged 6 months-4 years, ≥1-dose COVID-19 vaccination coverage was lower in rural counties (3.4%) than in urban counties (10.5%). Among children aged 6 months-4 years who received at least the first dose, only 7.0% were non-Hispanic Black or African American (Black), and 19.9% were Hispanic or Latino (Hispanic), although these demographic groups constitute 13.9% and 25.9% of the population, respectively (4). COVID-19 vaccination coverage among children aged 6 months-4 years is substantially lower than that among older children (5). Efforts are needed to improve vaccination coverage among children aged 6 months-4 years to reduce COVID-19-associated morbidity and mortality., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Understanding persistence and evolution of B cell clones after COVID-19 infection and vaccination is crucial for predicting responses against emerging viral variants and optimizing vaccines. Here, we collected longitudinal samples from patients with severe COVID-19 every third to seventh day during hospitalization and every third month after recovery. We profiled their antigen-specific immune cell dynamics by combining single-cell RNA-Seq, Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-Seq), and B cell receptor-Seq (BCR-Seq) with oligo-tagged antigen baits. While the proportion of Spike receptor binding domain-specific memory B cells (MBC) increased from 3 months after infection, the other Spike- and Nucleocapsid-specific B cells remained constant. All patients showed ongoing class switching and sustained affinity maturation of antigen-specific cells, and affinity maturation was not significantly increased early after vaccine. B cell analysis revealed a polyclonal response with limited clonal expansion; nevertheless, some clones detected during hospitalization, as plasmablasts, persisted for up to 1 year, as MBC. Monoclonal antibodies derived from persistent B cell families increased their binding and neutralization breadth and started recognizing viral variants by 3 months after infection. Overall, our findings provide important insights into the clonal evolution and dynamics of antigen-specific B cell responses in longitudinally sampled patients infected with COVID-19.

Objectives: In summer 2021, the number of COVID-19-associated hospitalizations in the United States increased with the surge of the SARS-CoV-2 Delta variant. We assessed how COVID-19 vaccine initiation and dose completion changed during the Delta variant surge, based on jurisdictional vaccination coverage before the surge., Methods: We analyzed COVID-19 vaccination data reported to the Centers for Disease Control and Prevention. We classified jurisdictions (50 states and the District of Columbia) into quartiles ranging from high to low first-dose vaccination coverage among people aged ≥12 years as of June 30, 2021. We calculated first-dose vaccination coverage as of June 30 and October 31, 2021, and stratified coverage by quartile, age (12-17, 18-64, ≥65 years), and sex. We assessed dose completion among those who initiated a 2-dose vaccine series., Results: Of 51 jurisdictions, 15 reached at least 70% vaccination coverage before the Delta variant surge (ie, as of June 30, 2021), while 35 reached that goal as of October 31, 2021. Jurisdictions in the lowest quartile of vaccination coverage (44.9%-54.9%) had the greatest absolute (9.7%-17.9%) and relative (18.1%-39.8%) percentage increase in vaccination coverage during July 1-October 31, 2021. Of those who received the first dose during this period across all jurisdictions, nearly 1 in 5 missed the second dose., Conclusions: Although COVID-19 vaccination initiation increased during July 1-October 31, 2021, in jurisdictions in the lowest quartile of vaccination coverage, coverage remained below that of jurisdictions in the highest quartile of vaccination coverage before the Delta variant surge. Efforts are needed to improve access to and increase confidence in COVID-19 vaccines, especially in low-coverage areas.

Objective: To use a model-based approach to estimate vaccination coverage of routinely recommended childhood and adolescent vaccines for the United States., Methods: We used a hierarchical model with retrospective cohort data from eleven IIS jurisdictions, which contains vaccination records submitted by providers. Numerators included data from 2014 to 2019 at the county level for 2.4 million children at age 24 months and 14.4 million adolescents aged 13-17. Age-appropriate Census populations were used as denominators. Covariates associated with childhood and adolescent vaccinations were included in the model. Model-based estimates for each county were generated and aggregated to the national level to produce national vaccination coverage estimates and compared to National Immunization Survey (NIS) estimates of vaccination coverage. Trends of estimated vaccination coverage were compared between the model-based approach and NIS., Results: From 2014 to 18, model-based national vaccination coverage estimates were within ten percentage points of NIS-Child vaccination coverage estimates for most vaccines among children at age 24 months. One notable difference was higher model-based vaccination coverage estimates for hepatitis B birth dose compared to NIS-Child coverage estimates. From 2014 to 19, model-based national vaccination coverage estimates were within ten percentage points of NIS-Teen vaccination coverage estimates for most vaccines among adolescents aged 13-17 years. Model-based vaccination coverage estimates were notably lower for varicella, MMR, and Hepatitis B compared to NIS-Teen coverage estimates among adolescents. Trends in estimates of national vaccination coverage were similar between model-based estimates for children and adolescents as compared to NIS-Child and NIS-Teen, respectively., Conclusions: A hierarchical model applied to data from IIS may be used to estimate coverage for routinely recommended vaccines among children and adolescents and allows for timely analyses of childhood and adolescent vaccines to quickly assess trends in vaccination coverage across the United States. Monitoring real-time vaccination coverage can help promote immunizations to protect children and adolescents against vaccine-preventable diseases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Time to AIDS in HIV-2 infection is approximately twice as long compared to in HIV-1 infection. Despite reduced viremia, HIV-2-infected individuals display signs of chronic immune activation. In HIV-1-infected individuals, B-cell hyperactivation is driven by continuous antigen exposure. However, the contribution of viremia to B-cell perturbations in HIV-2-infected individuals remains largely unexplored. Here, we used polychromatic flow cytometry, consensus hierarchical clustering and pseudotime trajectory inference to characterize B-cells in HIV-1- or HIV-2-infected and in HIV seronegative individuals. We observed increased frequencies of clusters containing hyperactivated T-bet high CD95 high CD27 int and proliferating T-bet + CD95 high CD27 + CD71 + memory B-cells in viremic HIV-1 ( p < 0.001 and p < 0.001, respectively), viremic HIV-2 ( p < 0.001 and p = 0.014, respectively) and in treatment-naïve aviremic HIV-2 ( p = 0.004 and p = 0.020, respectively)-infected individuals, compared to seronegative individuals. In contrast, these expansions were not observed in successfully treated HIV-1-infected individuals. Finally, pseudotime trajectory inference showed that T-bet-expressing hyperactivated and proliferating memory B-cell populations were located at the terminal end of two trajectories, in both HIV-1 and HIV-2 infections. As the treatment-naïve aviremic HIV-2-infected individuals, but not the successfully ART-treated HIV-1-infected individuals, showed B-cell perturbations, our data suggest that aviremic HIV-2-infected individuals would also benefit from antiretroviral treatment.

Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

A tree model identified adults age ≤34 years, Johnson & Johnson primary series recipients, people from racial/ethnic minority groups, residents of nonlarge metro areas, and those living in socially vulnerable communities in the South as less likely to be boosted. These findings can guide clinical/public health outreach toward specific subpopulations., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2022.)

To identify demographic factors associated with delaying or not receiving a second dose of the 2-dose primary mRNA COVID-19 vaccine series, we matched 323 million single Pfizer-BioNTech (https://www.pfizer.com) and Moderna (https://www.modernatx.com) COVID-19 vaccine administration records from 2021 and determined whether second doses were delayed or missed. We used 2 sets of logistic regression models to examine associated factors. Overall, 87.3% of recipients received a timely second dose (≤42 days between first and second dose), 3.4% received a delayed second dose (>42 days between first and second dose), and 9.4% missed the second dose. Persons more likely to have delayed or missed the second dose belonged to several racial/ethnic minority groups, were 18-39 years of age, lived in more socially vulnerable areas, and lived in regions other than the northeastern United States. Logistic regression models identified specific subgroups for providing outreach and encouragement to receive subsequent doses on time.

The Unified Protocol (UP) as a transdiagnostic intervention has primarily been applied in the treatment of anxiety disorders and in face-to-face-settings. The current study investigated the efficacy of a 10-week Internet-based adaptation of the UP for anxiety, depressive, and somatic symptom disorders. The trial was registered under DRKS00014820 at the German Clinical Trial Registry, DRKS. Participants (n = 129) were randomized to treatment or waitlist control. Significant treatment effects were found for symptom distress, satisfaction with life, positive/negative affect and markers of anxiety, depression, and somatic symptom burden (within-group Hedges' g = 0.32-1.38 and between-group g = 0.20-1.11). Treatment gains were maintained at 1- and 6-month-follow-up. Subgroup analyses showed comparable effects in participants with anxiety and depressive disorders. 26.6% dropped out of treatment and 35.38% did not provide post-treatment assessments. The results strengthen the application of the UP as an Internet-based treatment for alleviating symptom distress across emotional disorders. More research on the applicability for single disorders is needed and avenues to improve adherence and attrition rates should be explored., Competing Interests: The authors have declared that no competing interests exist.

We analyzed first-dose coronavirus disease vaccination coverage among US children 5-11 years of age during November-December 2021. Pediatric vaccination coverage varied widely by jurisdiction, age group, and race/ethnicity, and lagged behind vaccination coverage for adolescents aged 12-15 years during the first 2 months of vaccine rollout.

Influenza causes considerable morbidity and mortality in the United States. Between 2010 and 2020, an estimated 9-41 million cases resulted in 140,000-710,000 hospitalizations and 12,000-52,000 deaths annually (1). As the United States enters the 2021-22 influenza season, the potential impact of influenza illnesses is of concern given that influenza season will again coincide with the ongoing COVID-19 pandemic, which could further strain overburdened health care systems. The Advisory Committee on Immunization Practices (ACIP) recommends routine annual influenza vaccination for the 2021-22 influenza season for all persons aged ≥6 months who have no contraindications (2). To assess the potential impact of the COVID-19 pandemic on influenza vaccination coverage, the percentage change between administration of at least 1 dose of influenza vaccine during September-December 2020 was compared with the average administered in the corresponding periods in 2018 and 2019. The data analyzed were reported from 11 U.S. jurisdictions with high-performing state immunization information systems.* Overall, influenza vaccine administration was 9.0% higher in 2020 compared with the average in 2018 and 2019, combined. However, in 2020, the number of influenza vaccine doses administered to children aged 6-23 months and children aged 2-4 years, was 13.9% and 11.9% lower, respectively than the average for each age group in 2018 and 2019. Strategic efforts are needed to ensure high influenza vaccination coverage among all age groups, especially children aged 6 months-4 years who are not yet eligible to receive a COVID-19 vaccine. Administration of influenza vaccine and a COVID-19 vaccine among eligible populations is especially important to reduce the potential strain that influenza and COVID-19 cases could place on health care systems already overburdened by COVID-19., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

HIV-2 is less pathogenic compared to HIV-1. Still, disease progression may develop in aviremic HIV-2 infection, but the driving forces and mechanisms behind such development are unclear. Here, we aimed to reveal the immunophenotypic pattern associated with CD8 T-cell pathology in HIV-2 infection, in relation to viremia and markers of disease progression. The relationships between pathological differences of the CD8 T-cell memory population and viremia were analyzed in blood samples obtained from an occupational cohort in Guinea-Bissau, including HIV-2 viremic and aviremic individuals. For comparison, samples from HIV-1- or dually HIV-1/2-infected and seronegative individuals were obtained from the same cohort. CD8 T-cell exhaustion was evaluated by the combined expression patterns of activation, stimulatory and inhibitory immune checkpoint markers analyzed using multicolor flow cytometry and advanced bioinformatics. Unsupervised multidimensional clustering analysis identified a cluster of late differentiated CD8 T-cells expressing activation (CD38+, HLA-DR int/high ), co-stimulatory (CD226+/-), and immune inhibitory (2B4+, PD-1 high , TIGIT high ) markers that distinguished aviremic from viremic HIV-2, and treated from untreated HIV-1-infected individuals. This CD8 T-cell population displayed close correlations to CD4%, viremia, and plasma levels of IP-10, sCD14 and beta-2 microglobulin in HIV-2 infection. Detailed analysis revealed that aviremic HIV-2-infected individuals had higher frequencies of exhausted TIGIT+ CD8 T-cell populations lacking CD226, while reduced percentage of stimulation-receptive TIGIT-CD226+ CD8 T-cells, compared to seronegative individuals. Our results suggest that HIV-2 infection, independent of viremia, skews CD8 T-cells towards exhaustion and reduced co-stimulation readiness. Further knowledge on CD8 T-cell phenotypes might provide help in therapy monitoring and identification of immunotherapy targets., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Scharf, Pedersen, Johansson, Lindman, Olsen, Buggert, Wilhelmson, Månsson, Esbjörnsson, Biague, Medstrand, Norrgren, Karlsson, Jansson and the SWEGUB CORE Group.)

Although severe COVID-19 illness and hospitalization are more common among adults, these outcomes can occur in adolescents (1). Nearly one third of adolescents aged 12-17 years hospitalized with COVID-19 during March 2020-April 2021 required intensive care, and 5% of those hospitalized required endotracheal intubation and mechanical ventilation (2). On December 11, 2020, the Food and Drug Administration (FDA) issued Emergency Use Authorization (EUA) of the Pfizer-BioNTech COVID-19 vaccine for adolescents aged 16-17 years; on May 10, 2021, the EUA was expanded to include adolescents aged 12-15 years; and on August 23, 2021, FDA granted approval of the vaccine for persons aged ≥16 years. To assess progress in adolescent COVID-19 vaccination in the United States, CDC assessed coverage with ≥1 dose* and completion of the 2-dose vaccination series † among adolescents aged 12-17 years using vaccine administration data for 49 U.S. states (all except Idaho) and the District of Columbia (DC) during December 14, 2020-July 31, 2021. As of July 31, 2021, COVID-19 vaccination coverage among U.S. adolescents aged 12-17 years was 42.4% for ≥1 dose and 31.9% for series completion. Vaccination coverage with ≥1 dose varied by state (range = 20.2% [Mississippi] to 70.1% [Vermont]) and for series completion (range = 10.7% [Mississippi] to 60.3% [Vermont]). By age group, 36.0%, 40.9%, and 50.6% of adolescents aged 12-13, 14-15, and 16-17 years, respectively, received ≥1 dose; 25.4%, 30.5%, and 40.3%, respectively, completed the vaccine series. Improving vaccination coverage and implementing COVID-19 prevention strategies are crucial to reduce COVID-19-associated morbidity and mortality among adolescents and to facilitate safer reopening of schools for in-person learning., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

After the March 2020 declaration of the COVID-19 pandemic in the United States, an analysis of provider ordering data from the federally funded Vaccines for Children program found a substantial decrease in routine pediatric vaccine ordering (1), and data from New York City and Michigan indicated sharp declines in routine childhood vaccine administration in these areas (2,3). In November 2020, CDC interim guidance stated that routine vaccination of children and adolescents should remain an essential preventive service during the COVID-19 pandemic (4,5). To further understand the impact of the pandemic on routine childhood and adolescent vaccination, vaccine administration data during March-September 2020 from 10 U.S. jurisdictions with high-performing* immunization information systems were assessed. Fewer administered doses of routine childhood and adolescent vaccines were recorded in all 10 jurisdictions during March-September 2020 compared with those recorded during the same period in 2018 and 2019. The number of vaccine doses administered substantially declined during March-May 2020, when many jurisdictions enacted stay-at-home orders. After many jurisdictions lifted these orders, the number of vaccine doses administered during June-September 2020 approached prepandemic baseline levels, but did not increase to the level that would have been necessary to catch up children who did not receive routine vaccinations on time. This lag in catch-up vaccination might pose a serious public health threat that would result in vaccine-preventable disease outbreaks, especially in schools that have reopened for in-person learning. During the past few decades, the United States has achieved a substantial reduction in the prevalence of vaccine-preventable diseases driven in large part to the ongoing administration of routinely recommended pediatric vaccines. These efforts need to continue even during the COVID-19 pandemic to reduce the morbidity and mortality from vaccine-preventable diseases. Health care providers should assess the vaccination status of all pediatric patients, including adolescents, and contact those who are behind schedule to ensure that all children are fully vaccinated., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Approximately 60 million persons in the United States live in rural counties, representing almost one fifth (19.3%) of the population.* In September 2020, COVID-19 incidence (cases per 100,000 population) in rural counties surpassed that in urban counties (1). Rural communities often have a higher proportion of residents who lack health insurance, live with comorbidities or disabilities, are aged ≥65 years, and have limited access to health care facilities with intensive care capabilities, which places these residents at increased risk for COVID-19-associated morbidity and mortality (2,3). To better understand COVID-19 vaccination disparities across the urban-rural continuum, CDC analyzed county-level vaccine administration data among adults aged ≥18 years who received their first dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine, or a single dose of the Janssen COVID-19 vaccine (Johnson & Johnson) during December 14, 2020-April 10, 2021 in 50 U.S. jurisdictions (49 states and the District of Columbia [DC]). Adult COVID-19 vaccination coverage was lower in rural counties (38.9%) than in urban counties (45.7%) overall and among adults aged 18-64 years (29.1% rural, 37.7% urban), those aged ≥65 years (67.6% rural, 76.1% urban), women (41.7% rural, 48.4% urban), and men (35.3% rural, 41.9% urban). Vaccination coverage varied among jurisdictions: 36 jurisdictions had higher coverage in urban counties, five had higher coverage in rural counties, and five had similar coverage (i.e., within 1%) in urban and rural counties; in four jurisdictions with no rural counties, the urban-rural comparison could not be assessed. A larger proportion of persons in the most rural counties (14.6%) traveled for vaccination to nonadjacent counties (i.e., farther from their county of residence) compared with persons in the most urban counties (10.3%). As availability of COVID-19 vaccines expands, public health practitioners should continue collaborating with health care providers, pharmacies, employers, faith leaders, and other community partners to identify and address barriers to COVID-19 vaccination in rural areas (2)., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Compared with other age groups, older adults (defined here as persons aged ≥65 years) are at higher risk for COVID-19-associated morbidity and mortality and have therefore been prioritized for COVID-19 vaccination (1,2). Ensuring access to vaccines for older adults has been a focus of federal, state, and local response efforts, and CDC has been monitoring vaccination coverage to identify and address disparities among subpopulations of older adults (2). Vaccine administration data submitted to CDC were analyzed to determine the prevalence of COVID-19 vaccination initiation among adults aged ≥65 years by demographic characteristics and overall. Characteristics of counties with low vaccination initiation rates were quantified using indicators of social vulnerability data from the 2019 American Community Survey.* During December 14, 2020-April 10, 2021, nationwide, a total of 42,736,710 (79.1%) older adults had initiated vaccination. The initiation rate was higher among men than among women and varied by state. On average, counties with low vaccination initiation rates (<50% of older adults having received at least 1 vaccine dose), compared with those with high rates (≥75%), had higher percentages of older adults without a computer, living in poverty, without Internet access, and living alone. CDC, state, and local jurisdictions in partnerships with communities should continue to identify and implement strategies to improve access to COVID-19 vaccination for older adults, such as assistance with scheduling vaccination appointments and transportation to vaccination sites, or vaccination at home if needed for persons who are homebound. † Monitoring demographic and social factors affecting COVID-19 vaccine access for older adults and prioritizing efforts to ensure equitable access to COVID-19 vaccine are needed to ensure high coverage among this group., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

The U.S. COVID-19 vaccination program began in December 2020, and ensuring equitable COVID-19 vaccine access remains a national priority.* COVID-19 has disproportionately affected racial/ethnic minority groups and those who are economically and socially disadvantaged (1,2). Thus, achieving not just vaccine equality (i.e., similar allocation of vaccine supply proportional to its population across jurisdictions) but equity (i.e., preferential access and administra-tion to those who have been most affected by COVID-19 disease) is an important goal. The CDC social vulnerability index (SVI) uses 15 indicators grouped into four themes that comprise an overall SVI measure, resulting in 20 metrics, each of which has national and state-specific county rankings. The 20 metric-specific rankings were each divided into lowest to highest tertiles to categorize counties as low, moderate, or high social vulnerability counties. These tertiles were combined with vaccine administration data for 49,264,338 U.S. residents in 49 states and the District of Columbia (DC) who received at least one COVID-19 vaccine dose during December 14, 2020-March 1, 2021. Nationally, for the overall SVI measure, vaccination coverage was higher (15.8%) in low social vulnerability counties than in high social vulnerability counties (13.9%), with the largest coverage disparity in the socioeconomic status theme (2.5 percentage points higher coverage in low than in high vulnerability counties). Wide state variations in equity across SVI metrics were found. Whereas in the majority of states, vaccination coverage was higher in low vulnerability counties, some states had equitable coverage at the county level. CDC, state, and local jurisdictions should continue to monitor vaccination coverage by SVI metrics to focus public health interventions to achieve equitable coverage with COVID-19 vaccine., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Rational design of chimeric antigen receptors (CARs) with optimized anticancer performance mandates detailed knowledge of how CARs engage tumor antigens and how antigen engagement triggers activation. We analyzed CAR-mediated antigen recognition via quantitative, single-molecule, live-cell imaging and found the sensitivity of CAR T cells toward antigen approximately 1,000-times reduced as compared to T cell antigen-receptor-mediated recognition of nominal peptide-major histocompatibility complexes. While CARs outperformed T cell antigen receptors with regard to antigen binding within the immunological synapse, proximal signaling was significantly attenuated due to inefficient recruitment of the tyrosine-protein kinase ZAP-70 to ligated CARs and its reduced concomitant activation and subsequent release. Our study exposes signaling deficiencies of state-of-the-art CAR designs, which presently limit the efficacy of CAR T cell therapies to target tumors with diminished antigen expression.

While the relationship of protective human leukocyte antigen (HLA) class I alleles and HIV progression is well defined, the interaction of HLA-mediated protection and CD8 T-cell exhaustion is less well characterized. To gain insight into the influence of HLA-B*57:01 on the deterioration of CD8 T-cell responses during HIV infection in the absence of antiretroviral treatment, we compared HLA-B*57:01-restricted HIV-specific CD8 T-cell responses to responses restricted by other HLA class I alleles longitudinally after control of peak viremia. Detailed characterization of polyfunctionality, differentiation phenotypes, transcription factor, and inhibitory receptor expression revealed progression of CD8 T-cell exhaustion over the course of the infection in both patient groups. However, early effects on the phenotype of the total CD8 T-cell population were apparent only in HLA-B*57-negative patients. The HLA-B*57:01-restricted, HIV epitope-specific CD8 T-cell responses showed beneficial functional patterns and significantly lower frequencies of inhibitory receptor expression, i.e., PD-1 and coexpression of PD-1 and TIGIT, within the first year of infection. Coexpression of PD-1 and TIGIT was correlated with clinical markers of disease progression and declining percentages of the T-bet hi Eomes dim CD8 T-cell population. In accordance with clinical and immunological deterioration in the HLA-B*57:01 group, the difference in PD-1 and TIGIT receptor expression did not persist to later stages of the disease. IMPORTANCE Given the synergistic nature of TIGIT and PD-1, the coexpression of those inhibitory receptors should be considered when evaluating T-cell pathogenesis, developing immunomodulatory therapies or vaccines for HIV, and when using immunotherapy or vaccination for other causes in HIV-infected patients. HIV-mediated T-cell exhaustion influences the patient´s disease progression, immune system and subsequently non-AIDS complications, and efficacy of vaccinations against other pathogens. Consequently, the possibilities of interfering with exhaustion are numerous. Expanding the use of immunomodulatory therapies to include HIV treatment depends on information about possible targets and their role in the deterioration of the immune system. Furthermore, the rise of immunotherapies against cancer and elevated cancer incidence in HIV-infected patients together increase the need for detailed knowledge of T-cell exhaustion and possible interactions. A broader approach to counteract immune exhaustion to alleviate complications and improve efficacy of other vaccines also promises to increase patients' health and quality of life., (Copyright © 2020 Scharf et al.)

Malignant melanoma is an aggressive type of cancer and the deadliest form of skin cancer. Even though enormous efforts have been undertaken, in particular the treatment options against the metastasizing form are challenging and the prognosis is generally poor. A novel therapeutical approach is the application of secondary plant constituents occurring in food and food products. Herein, the effect of the dietary chalcone cardamonin, inter alia found in Alpinia species, was tested using human malignant melanoma cells. These data were compared to cardamonin treated normal melanocytes and dermal fibroblasts representing healthy cells. To investigate the impact of cardamonin on tumor and normal cells, it was added to monolayer cell cultures and cytotoxicity, proliferation, tumor invasion, and apoptosis were studied with appropriate cell biological and biochemical methods. Cardamonin treatment resulted in an apoptosis-mediated increase in cytotoxicity towards tumor cells, a decrease in their proliferation rate, and a lowered invasive capacity, whereas the viability of melanocytes and fibroblasts was hardly affected at such concentrations. A selective cytotoxic effect of cardamonin on melanoma cells compared to normal (healthy) cells was shown in vitro. This study along with others highlights that dietary chalcones may be a valuable tool in anticancer therapies which has to be proven in the future in vivo., Competing Interests: The authors have declared that no competing interests exist.

Since neutralizing antibodies (NAb) targeting the human cytomegalovirus (HCMV) pentamer complex (PC) potently block HCMV host cell entry, anti-PC NAb induction is thought to be important for a vaccine formulation to prevent HCMV infection. By developing a vaccine strategy based on soluble PC protein and using a previously generated Modified Vaccinia Ankara vector co-expressing all five PC subunits (MVA-PC), we compared HCMV NAb induction by homologous immunization using prime-boost vaccine regimen employing only PC protein or MVA-PC and heterologous immunization using prime-boost combinations of PC protein and MVA-PC. Utilizing a recently isolated anti-PC NAb, we produced highly pure soluble PC protein that displayed conformational and linear neutralizing epitopes, interfered with HCMV entry, and was recognized by antibodies induced by HCMV during natural infection. Mice vaccinated by different immunization routes with the purified PC protein in combination with a clinically approved adjuvant formulation elicited high-titer and durable HCMV NAb. While MVA-PC and soluble PC protein either alone or in combination elicited robust HCMV NAb, significantly different potencies of these vaccine approaches were observed in dependence on immunization schedule. Using only two immunizations, vaccination with MVA-PC alone or prime-boost combinations of MVA-PC and PC protein was significantly more effective in stimulating HCMV NAb than immunization with PC protein alone. In contrast, with three immunizations, NAb induced by soluble PC protein either alone or combined with two boosts of MVA-PC increased to levels that exceeded NAb titer stimulated by MVA-PC alone. These results provide insights into the potency of soluble protein and MVA to elicit NAb by the HCMV PC via homologous and heterologous prime-boost immunization, which may contribute to develop clinically deployable vaccine strategies to prevent HCMV infection.

The HIV-1 envelope (Env) glycoprotein binds to host cell receptors to mediate membrane fusion. The prefusion Env trimer is stabilized by V1V2 loops that interact at the trimer apex. Broadly neutralizing antibodies (bNAbs) against V1V2 loops, exemplified by PG9, bind asymmetrically as a single Fab to the apex of the symmetric Env trimer using a protruding CDRH3 to penetrate the Env glycan shield. Here we characterized a distinct mode of V1V2 epitope recognition by the new bNAb BG1 in which two Fabs bind asymmetrically per Env trimer using a compact CDRH3. Comparisons between cryo-EM structures of Env trimer complexed with BG1 (6.2 Å resolution) and PG9 (11.5 Å resolution) revealed a new V1V2-targeting strategy by BG1. Analyses of the EM structures provided information relevant to vaccine design including molecular details for different modes of asymmetric recognition of Env trimer and a binding model for BG1 recognition of V1V2 involving glycan flexibility.

Some HIV-1-infected patients develop broad and potent HIV-1 neutralizing antibodies (bNAbs) that when passively transferred to mice or macaques can treat or prevent infection. However, bNAbs typically fail to neutralize coexisting autologous viruses due to antibody-mediated selection against sensitive viral strains. We describe an HIV-1 controller expressing HLA-B57*01 and HLA-B27*05 who maintained low viral loads for 30 years after infection and developed broad and potent serologic activity against HIV-1. Neutralization was attributed to three different bNAbs targeting nonoverlapping sites on the HIV-1 envelope trimer (Env). One of the three, BG18, an antibody directed against the glycan-V3 portion of Env, is the most potent member of this class reported to date and, as revealed by crystallography and electron microscopy, recognizes HIV-1 Env in a manner that is distinct from other bNAbs in this class. Single-genome sequencing of HIV-1 from serum samples obtained over a period of 9 years showed a diverse group of circulating viruses, 88.5% (31 of 35) of which remained sensitive to at least one of the temporally coincident autologous bNAbs and the individual's serum. Thus, bNAb-sensitive strains of HIV-1 coexist with potent neutralizing antibodies that target the virus and may contribute to control in this individual. When administered as a mix, the three bNAbs controlled viremia in HIV-1 YU2 -infected humanized mice. Our finding suggests that combinations of bNAbs may contribute to control of HIV-1 infection., (Copyright © 2017, American Association for the Advancement of Science.)

HIV-specific CD8 + T cells demonstrate an exhausted phenotype associated with increased expression of inhibitory receptors, decreased functional capacity, and a skewed transcriptional profile, which are only partially restored by antiretroviral treatment (ART). Expression levels of the inhibitory receptor, T cell immunoglobulin and ITIM domain (TIGIT), the co-stimulatory receptor CD226 and their ligand PVR are altered in viral infections and cancer. However, the extent to which the TIGIT/CD226/PVR-axis is affected by HIV-infection has not been characterized. Here, we report that TIGIT expression increased over time despite early initiation of ART. HIV-specific CD8 + T cells were almost exclusively TIGIT + , had an inverse expression of the transcription factors T-bet and Eomes and co-expressed PD-1, CD160 and 2B4. HIV-specific TIGIT hi cells were negatively correlated with polyfunctionality and displayed a diminished expression of CD226. Furthermore, expression of PVR was increased on CD4 + T cells, especially T follicular helper (Tfh) cells, in HIV-infected lymph nodes. These results depict a skewing of the TIGIT/CD226 axis from CD226 co-stimulation towards TIGIT-mediated inhibition of CD8 + T cells, despite early ART. These findings highlight the importance of the TIGIT/CD226/PVR axis as an immune checkpoint barrier that could hinder future "cure" strategies requiring potent HIV-specific CD8 + T cells.

Efforts to elicit broadly neutralizing antibodies (bNAbs) against HIV-1 require understanding germline bNAb recognition of HIV-1 envelope glycoprotein (Env). The VRC01-class bNAb family derived from the VH1-2*02 germline allele arose in multiple HIV-1-infected donors, yet targets the CD4-binding site on Env with common interactions. Modified forms of the 426c Env that activate germline-reverted B cell receptors are candidate immunogens for eliciting VRC01-class bNAbs. We present structures of germline-reverted VRC01-class bNAbs alone and complexed with 426c-based gp120 immunogens. Germline bNAb-426c gp120 complexes showed preservation of VRC01-class signature residues and gp120 contacts, but detectably different binding modes compared to mature bNAb-gp120 complexes. Unlike typical antibody-antigen interactions, VRC01-class germline antibodies exhibited preformed antigen-binding conformations for recognizing immunogens. Affinity maturation introduced substitutions increasing induced-fit recognition and electropositivity, potentially to accommodate negatively-charged complex-type N-glycans on gp120. These results provide general principles relevant to the unusual evolution of VRC01-class bNAbs and guidelines for structure-based immunogen design.

Previous studies have shown that sera from HIV-1-infected individuals contain antibodies able to mediate antibody-dependent cellular cytotoxicity (ADCC). These antibodies preferentially recognize envelope glycoprotein (Env) epitopes induced upon CD4 binding. Here, we show that a highly conserved tryptophan at position 69 of the gp120 inner domain is important for ADCC mediated by anti-cluster A antibodies and sera from HIV-1-infected individuals., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

The CD4 binding site (CD4bs) on the envelope glycoprotein is a major site of vulnerability that is conserved among different HIV-1 isolates. Many broadly neutralizing antibodies (bNAbs) to the CD4bs belong to the VRC01 class, sharing highly restricted origins, recognition mechanisms and viral escape pathways. We sought to isolate new anti-CD4bs bNAbs with different origins and mechanisms of action. Using a gp120 2CC core as bait, we isolated antibodies encoded by IGVH3-21 and IGVL3-1 genes with long CDRH3s that depend on the presence of the N-linked glycan at position-276 for activity. This binding mode is similar to the previously identified antibody HJ16, however the new antibodies identified herein are more potent and broad. The most potent variant, 179NC75, had a geometric mean IC80 value of 0.42 μg/ml against 120 Tier-2 HIV-1 pseudoviruses in the TZM.bl assay. Although this group of CD4bs glycan-dependent antibodies can be broadly and potently neutralizing in vitro, their in vivo activity has not been tested to date. Here, we report that 179NC75 is highly active when administered to HIV-1-infected humanized mice, where it selects for escape variants that lack a glycan site at position-276. The same glycan was absent from the virus isolated from the 179NC75 donor, implying that the antibody also exerts selection pressure in humans.

The HIV-1 envelope (Env) spike contains limited epitopes for broadly neutralizing antibodies (bNAbs); thus, most neutralizing antibodies are strain specific. The 8ANC195 epitope, defined by crystal and electron microscopy (EM) structures of bNAb 8ANC195 complexed with monomeric gp120 and trimeric Env, respectively, spans the gp120 and gp41 Env subunits. To investigate 8ANC195's gp41 epitope at higher resolution, we solved a 3.58 Å crystal structure of 8ANC195 complexed with fully glycosylated Env trimer, revealing 8ANC195 insertion into a glycan shield gap to contact gp120 and gp41 glycans and protein residues. To determine whether 8ANC195 recognizes the CD4-bound open Env conformation that leads to co-receptor binding and fusion, one of several known conformations of virion-associated Env, we solved EM structures of an Env/CD4/CD4-induced antibody/8ANC195 complex. 8ANC195 binding partially closed the CD4-bound trimer, confirming structural plasticity of Env by revealing a previously unseen conformation. 8ANC195's ability to bind different Env conformations suggests advantages for potential therapeutic applications., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A subset of individuals infected with HIV-1 develops broadly neutralizing antibodies (bNAbs) that can prevent infection, but it has not yet been possible to elicit these antibodies by immunization. To systematically explore how immunization might be tailored to produce them, we generated mice expressing the predicted germline or mature heavy chains of a potent bNAb to the CD4 binding site (CD4bs) on the HIV-1 envelope glycoprotein (Env). Immunogens specifically designed to activate B cells bearing germline antibodies are required to initiate immune responses, but they do not elicit bNAbs. In contrast, native-like Env trimers fail to activate B cells expressing germline antibodies but elicit bNAbs by selecting for a restricted group of light chains bearing specific somatic mutations that enhance neutralizing activity. The data suggest that vaccination to elicit anti-HIV-1 antibodies will require immunization with a succession of related immunogens., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose of Review: This review highlights recent developments in HIV-1 antibody engineering and discusses the effects of increased polyreactivity on serum half-lives of engineered antibodies., Recent Findings: Recent studies have uncovered a wealth of information about the relationship between the sequences and efficacies of anti-HIV-1 antibodies through a combination of bioinformatics, structural characterization and in vivo studies. This knowledge has stimulated efforts to enhance antibody breadth and potency for therapeutic use. Although some engineered antibodies have shown increased polyreactivity and short half-lives, promising efforts are circumventing these problems., Summary: Antibodies are desirable as therapeutics due to their ability to recognize targets with both specificity and high affinity. Furthermore, the ability of antibodies to stimulate Fc-mediated effector functions can increase their utility. Thus, mAbs have become central to strategies for the treatment of various diseases. Using both targeted and library-based approaches, antibodies can be engineered to improve their therapeutic properties. This article will discuss recent antibody engineering efforts to improve the breadth and potency of anti-HIV-1 antibodies. The polyreactivity of engineered HIV-1 bNAbs and the effect on serum half-life will be explored along with strategies to overcome problems introduced by engineering antibodies. Finally, advances in creating bispecific anti-HIV-1 reagents are discussed.

Broadly neutralizing antibodies (bNAbs) to HIV-1 envelope glycoprotein (Env) can prevent infection in animal models. Characterized bNAb targets, although key to vaccine and therapeutic strategies, are currently limited. We defined a new site of vulnerability by solving structures of bNAb 8ANC195 complexed with monomeric gp120 by X-ray crystallography and trimeric Env by electron microscopy. The site includes portions of gp41 and N-linked glycans adjacent to the CD4-binding site on gp120, making 8ANC195 the first donor-derived anti-HIV-1 bNAb with an epitope spanning both Env subunits. Rather than penetrating the glycan shield by using a single variable-region CDR loop, 8ANC195 inserted its entire heavy-chain variable domain into a gap to form a large interface with gp120 glycans and regions of the gp120 inner domain not contacted by other bNAbs. By isolating additional 8ANC195 clonal variants, we identified a more potent variant, which may be valuable for therapeutic approaches using bNAb combinations with nonoverlapping epitopes., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

Despite 30 years of effort, there is no effective vaccine for HIV-1. However, antibodies can prevent HIV-1 infection in humanized mice and macaques when passively transferred. New single-cell-based methods have uncovered many broad and potent donor-derived antibodies, and structural studies have revealed the molecular bases for their activities. The new data suggest why such antibodies are difficult to elicit and inform HIV-1 vaccine development efforts. In addition to protecting against infection, the newly identified antibodies can suppress active infections in mice and macaques, suggesting they could be valuable additions to anti-HIV-1 therapies and to strategies to eradicate HIV-1 infection., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The nature of the antigens recognized by γδ T cells and their potential recognition of major histocompatibility complex (MHC)-like molecules has remained unclear. Members of the CD1 family of lipid-presenting molecules are suggested ligands for Vδ1 TCR-expressing γδ T cells, the major γδ lymphocyte population in epithelial tissues. We crystallized a Vδ1 TCR in complex with CD1d and the self-lipid sulfatide, revealing the unusual recognition of CD1d by germline Vδ1 residues spanning all complementarity-determining region (CDR) loops, as well as sulfatide recognition separately encoded by nongermline CDR3δ residues. Binding and functional analysis showed that CD1d presenting self-lipids, including sulfatide, was widely recognized by gut Vδ1+ γδ T cells. These findings provide structural demonstration of MHC-like recognition of a self-lipid by γδ T cells and reveal the prevalence of lipid recognition by innate-like T cell populations., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Despite 30 years of study, there is no HIV-1 vaccine and, until recently, there was little hope for a protective immunization. Renewed optimism in this area of research comes in part from the results of a recent vaccine trial and the use of single-cell antibody-cloning techniques that uncovered naturally arising, broad and potent HIV-1-neutralizing antibodies (bNAbs). These antibodies can protect against infection and suppress established HIV-1 infection in animal models. The finding that these antibodies develop in a fraction of infected individuals supports the idea that new approaches to vaccination might be developed by adapting the natural immune strategies or by structure-based immunogen design. Moreover, the success of passive immunotherapy in small-animal models suggests that bNAbs may become a valuable addition to the armamentarium of drugs that work against HIV-1.

Advances in single-cell antibody cloning methods have led to the identification of a variety of broadly neutralizing anti-HIV-1 antibodies. We developed a computational tool (Antibody Database) to help identify critical residues on the HIV-1 envelope protein whose natural variation affects antibody activity. Our simplifying assumption was that, for a given antibody, a significant portion of the dispersion of neutralization activity across a panel of HIV-1 strains is due to the amino acid identity or glycosylation state at a small number of specific sites, each acting independently. A model of an antibody's neutralization IC50 was developed in which each site contributes a term to the logarithm of the modeled IC50. The analysis program attempts to determine the set of rules that minimizes the sum of the residuals between observed and modeled IC50 values. The predictive quality of the identified rules may be assessed in part by whether there is support for rules within individual viral clades. As a test case, we analyzed antibody 8ANC195, an anti-glycoprotein gp120 antibody of unknown specificity. The model for this antibody indicated that several glycosylation sites were critical for neutralization. We evaluated this prediction by measuring neutralization potencies of 8ANC195 against HIV-1 in vitro and in an antibody therapy experiment in humanized mice. These experiments confirmed that 8ANC195 represents a distinct class of glycan-dependent anti-HIV-1 antibody and validated the utility of computational analysis of neutralization panel data.

β-D-mannosyl phosphomycoketide (C32-MPM), a naturally occurring glycolipid found in the cell walls of Mycobacterium tuberculosis, acts as a potent antigen to activate T-cells upon presentation by CD1c protein. The lipid portion of C32-MPM contains a C32-mycoketide, consisting of a saturated oligoisoprenoid chain with five chiral methyl branches. Here we develop several stereocontrolled approaches to assemble the oligoisoprenoid chain with high stereopurity (>96%) using Julia-Kocienski olefinations followed by diimide reduction. By careful choice of olefination sites, we could derive all chirality from a single commercial compound, methyl (2S)-3-hydroxy-2-methylpropionate (>99% ee). Our approach is the first highly stereocontrolled method to prepare C32-MPM molecule with >96% stereopurity from a single >99% ee starting material. We anticipate that our methods will facilitate the highly stereocontrolled synthesis of a variety of other natural products containing chiral oligoisoprenoid-like chains, including vitamins, phytol, insect pheromones, and archaeal lipids.

Invariant natural killer T (iNKT) cells are innate T lymphocytes that specifically recognize α-linked glycosphingolipids (α-GSLs) as antigens presented by CD1d molecules. Activating iNKT cells by administering α-GSLs improves disease outcomes in murine cancer models and, thus, there is great interest in the clinical potential of these lipids for treating human cancers. However, humans possess several other CD1 isoforms that are not present in mice and it is not clear whether these CD1 molecules, which also bind lipids, affect human iNKT cell responses. We demonstrate here that CD1c, which is co-expressed with CD1d on blood dendritic cells and on a fraction of B cells, is able to present α-galactosylceramide (α-GalCer) as a weak agonist to human iNKT cells, and that the presence of CD1c synergistically enhances α-GalCerdependent activation of iNKT cells by CD1d. Primary human B cells expressing CD1c induced stronger iNKT cell responses to α-GalCer than the CD1c- subset, and an antibody against CD1c inhibited iNKT cell cytokine secretion. These results suggest that therapeutic activation of human iNKT cells by α-GSLs will be driven preferentially by CD1c+ cell types. Thus, B cell neoplasias that co-express CD1c and CD1d may be particularly susceptible to α-GSL therapy, and cancer vaccines using α-GSLs as adjuvants may be most effective when presented by CD1c+ antigen-presenting cells.

Efforts to design an effective antibody-based vaccine against HIV-1 would benefit from understanding how germ-line B-cell receptors (BCRs) recognize the HIV-1 gp120/gp41 envelope spike. Potent VRC01-like (PVL) HIV-1 antibodies derived from the VH1-2*02 germ-line allele target the conserved CD4 binding site on gp120. A bottleneck for design of immunogens capable of eliciting PVL antibodies is that VH1-2*02 germ-line BCR interactions with gp120 are uncharacterized. Here, we report the structure of a VH1-2*02 germ-line antibody alone and a germ-line heavy-chain/mature light-chain chimeric antibody complexed with HIV-1 gp120. VH1-2*02 residues make extensive contacts with the gp120 outer domain, including all PVL signature and CD4 mimicry interactions, but not critical CDRH3 contacts with the gp120 inner domain and bridging sheet that are responsible for the improved potency of NIH45-46 over closely related clonal variants, such as VRC01. Our results provide insight into initial recognition of HIV-1 by VH1-2*02 germ-line BCRs and may facilitate the design of immunogens tailored to engage and stimulate broad and potent CD4 binding site antibodies.

Broadly neutralizing HIV antibodies (bNAbs) can recognize carbohydrate-dependent epitopes on gp120. In contrast to previously characterized glycan-dependent bNAbs that recognize high-mannose N-glycans, PGT121 binds complex-type N-glycans in glycan microarrays. We isolated the B-cell clone encoding PGT121, which segregates into PGT121-like and 10-1074-like groups distinguished by sequence, binding affinity, carbohydrate recognition, and neutralizing activity. Group 10-1074 exhibits remarkable potency and breadth but no detectable binding to protein-free glycans. Crystal structures of unliganded PGT121, 10-1074, and their likely germ-line precursor reveal that differential carbohydrate recognition maps to a cleft between complementarity determining region (CDR)H2 and CDRH3. This cleft was occupied by a complex-type N-glycan in a "liganded" PGT121 structure. Swapping glycan contact residues between PGT121 and 10-1074 confirmed their importance for neutralization. Although PGT121 binds complex-type N-glycans, PGT121 recognized high-mannose-only HIV envelopes in isolation and on virions. As HIV envelopes exhibit varying proportions of high-mannose- and complex-type N-glycans, these results suggest promiscuous carbohydrate interactions, an advantageous adaptation ensuring neutralization of all viruses within a given strain.

The molecular mechanisms by which γδ T cells recognize ligand remain a mystery. The non-classical MHC molecule T22 represents the best characterized ligand for murine γδ T cells, with a motif (W … EGYEL) present in the γδ T cell receptor complementary-determining region 3δ (CDR3δ) loop mediating γδ T cell recognition of this molecule. Produced through V(D)J recombination, this loop is quite diverse, with different numbers and chemical types of amino acids between Trp and EGYEL, which have unknown functional consequences for T22 recognition. We have investigated the biophysical and structural effects of CDR3δ loop diversity, revealing a range of affinities for T22 but a common thermodynamic pattern. Mutagenesis of these CDR3δ loops defines the key anchor residues involved in T22 recognition as W … EGYEL, similar to those found for the G8 CDR3δ loop, and demonstrates that spacer residues modulate but are not required for T22 recognition. Comparison of the location of these residues in the T22 interface reveals a striking similarity to peptide anchor residues in classically presented MHC peptides, with the key Trp residue of the CDR3δ motif completing the deficient peptide-binding groove of T22. This suggests that γδ T cell recognition of T22 utilizes the conserved ligand-presenting nature of the MHC fold.

CD1 molecules function to present lipid-based antigens to T cells. Here we present the crystal structure of CD1c at 2.5 Å resolution, in complex with the pathogenic Mycobacterium tuberculosis antigen mannosyl-β1-phosphomycoketide (MPM). CD1c accommodated MPM's methylated alkyl chain exclusively in the A' pocket, aided by a unique exit portal underneath the α1 helix. Most striking was an open F' pocket architecture lacking the closed cavity structure of other CD1 molecules, reminiscent of peptide binding grooves of classical major histocompatibility complex molecules. This feature, combined with tryptophan-fluorescence quenching during loading of a dodecameric lipopeptide antigen, provides a compelling model by which both the lipid and peptide moieties of the lipopeptide are involved in CD1c presentation of lipopeptides.

Natural killer T (NKT) cells are a subset of T lymphocytes with potent immunoregulatory properties. Recognition of self-antigens presented by CD1d molecules is an important route of NKT cell activation; however, the molecular identity of specific autoantigens that stimulate human NKT cells remains unclear. Here, we have analyzed human NKT cell recognition of CD1d cellular ligands. The most clearly antigenic species was lyso-phosphatidylcholine (LPC). Diacylated phosphatidylcholine and lyso-phosphoglycerols differing in the chemistry of the head group stimulated only weak responses from human NKT cells. However, lyso-sphingomyelin, which shares the phosphocholine head group of LPC, also activated NKT cells. Antigen-presenting cells pulsed with LPC were capable of stimulating increased cytokine responses by NKT cell clones and by freshly isolated peripheral blood lymphocytes. These results demonstrate that human NKT cells recognize cholinated lyso-phospholipids as antigens presented by CD1d. Since these lyso-phospholipids serve as lipid messengers in normal physiological processes and are present at elevated levels during inflammatory responses, these findings point to a novel link between NKT cells and cellular signaling pathways that are associated with human disease pathophysiology., Competing Interests: The authors have declared that no competing interests exist.

Parenting a child with, or at risk for, a developmental delay or disability can be stressful. Abidin's parenting stress model was used as a framework to examine how several maternal, child, and family factors predict parent stress outcomes. Stepwise regression models revealed that maternal and child factors were significant contributors to parenting stress. However, family factors (income and family functioning) were not retained. Parenting stress was lower when child (cognitive and adaptive ability) and maternal (depression and child care competence) characteristics were more positive. Child cognitive ability was a strong contributor to total parenting stress and two parenting stress subscales. Findings suggest that these parents need stress lowering interventions such as supportive child care, respite relief, and a child behaviour-focused program.

Background: Cardiovascular disease is now well established as a multifactorial disease. In a given individual, the level of cardiovascular risk is due to the interaction between genetic and environmental components. The BIP cohort comprises 3000 patients with cardiovascular disease who were tested for the benefits of bezafibrate treatment. This cohort has the data for the lipid profile of each individual, fibrinogen, insulin, as well as clinical, demographic and lifestyle parameters., Objectives: To genotype up to 64 variable sites in 36 genes in the BIP cohort. The genes tested in this assay are involved in pathways implicated in the development and progression of atherosclerotic plaques, lipid and homocystein metabolism, blood pressure regulation, thrombosis, rennin-angiotensin system, platelet aggregation, and leukocyte adhesion., Methods: DNA was extracted from 1000 Israeli patients from the BIP cohort. A multilocus assay, developed by the Roche Molecular System, was used for genotyping. Allele frequencies for some of the markers were compared to the published frequencies in a healthy population (the French Stanislas cohort, n = 1480)., Results: Among the 26 comparable alleles checked in the two cohorts, 16 allele frequencies were significantly different from the healthy French population: ApoE(E3, E2, E4), ApoB (71ile), ApoC (3482T, 455C, 1100T, 3175G, 3206G), CETP(405val), ACE (Del), AGT (235thr), ELAM (128arg); P < 0001 and LPL (93G, 291Ser, 447ter); P < 005., Conclusions: Although a comparable healthy Israeli population study is needed for more precise interpretation of these results, frequency differences in these polymorphic alleles--associated with lipid metabolism, renin-angiotensin system and leukocyte adhesion mechanism--between CVD patients and healthy individuals nevertheless implicate these candidate genes as predisposing for CVD.