Structural characterization of infection- and vaccination-elicited antibodies in complex with antigen provides insight into the evolutionary arms race between the host and the pathogen and informs ...rational vaccine immunogen design. We isolated a germ line-encoded monoclonal antibody (mAb) from plasmablasts activated upon mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and determined its structure in complex with the spike glycoprotein by electron cryomicroscopy (cryo-EM). We show that the mAb engages a previously uncharacterized neutralizing epitope on the spike N-terminal domain (NTD). The high-resolution structure reveals details of the intermolecular interactions and shows that the mAb inserts its heavy complementarity-determining region 3 (HCDR3) loop into a hydrophobic NTD cavity previously shown to bind a heme metabolite, biliverdin. We demonstrate direct competition with biliverdin and that, because of the conserved nature of the epitope, the mAb maintains binding to viral variants B.1.1.7 (alpha), B.1.351 (beta), B.1.617.2 (delta), and B.1.1.529 (omicron). Our study describes a novel conserved epitope on the NTD that is readily targeted by vaccine-induced antibody responses.
We report the first structure of a vaccine-induced antibody to SARS-CoV-2 spike isolated from plasmablasts 7 days after vaccination. The genetic sequence of the antibody PVI.V6-14 suggests that it is completely unmutated, meaning that this type of B cell did not undergo somatic hypermutation or affinity maturation; this cell was likely already present in the donor and was activated by the vaccine. This is, to our knowledge, also the first structure of an unmutated antibody in complex with its cognate antigen. PVI.V6-14 binds a novel, conserved epitope on the N-terminal domain (NTD) and neutralizes the original viral strain. PVI.V6-14 also binds the newly emerged variants B.1.1.7 (alpha), B.1.351 (beta), B.1.617.2 (delta), and B.1.1.529 (omicron). Given that this antibody was likely already present in the donor prior to vaccination, we believe that this antibody class could potentially "keep up" with the new variants, should they continue to emerge, by undergoing somatic hypermutation and affinity maturation.
The piriform cortex (PCX) is the largest component of the olfactory cortex and is hypothesized to be the locus of odor object formation. The distributed odorant representation found in PCX contrasts ...sharply with the topographical representation seen in other primary sensory cortices, making it difficult to test this view. Recent work in PCX has focused on functional characteristics of these distributed afferent and association fiber systems. However, information regarding the efferent projections of PCX and how those may be involved in odor representation and object recognition has been largely ignored. To investigate this aspect of PCX, we have used the efferent pathway from mouse PCX to the orbitofrontal cortex (OFC). Using double fluorescent retrograde tracing, we identified the output neurons (OPNs) of the PCX that project to two subdivisions of the OFC, the agranular insula and the lateral orbitofrontal cortex (AI-OPNs and LO-OPNs, respectively). We found that both AI-OPNs and LO-OPNs showed a distinct spatial topography within the PCX and fewer than 10% projected to both the AI and the LO as judged by double-labeling. These data revealed that the efferent component of the PCX may be topographically organized. Further, these data suggest a model for functional organization of the PCX in which the OPNs are grouped into parallel output circuits that provide olfactory information to different higher centers. The distributed afferent input from the olfactory bulb and the local PCX association circuits would then ensure a complete olfactory representation, pattern recognition capability, and neuroplasticity in each efferent circuit.
Significance The mammalian olfactory system is capable of detecting and discriminating a vast and diverse array of small organic molecules or odorants. Complex blends of these chemicals are finally perceived as a unified odor object—for example, a rose contains dozens of active compounds. The piriform cortex (PCX) is the largest component of the olfactory cortex and has been hypothesized to be the locus of odor object formation. However, the PCX shows a distributed odorant representation that contrasts sharply with the topographical representation typically seen in the other primary sensory cortices. In this article, we explore an alternative organizational principle for the PCX based on where neurons are sending their output, rather than where these neurons are receiving their input.
The emergence of SARS-CoV-2 antigenic variants with increased transmissibility is a public health threat. Some variants show substantial resistance to neutralization by SARS-CoV-2 infection- or ...vaccination-induced antibodies. Here, we analyzed receptor binding domain-binding monoclonal antibodies derived from SARS-CoV-2 mRNA vaccine-elicited germinal center B cells for neutralizing activity against the WA1/2020 D614G SARS-CoV-2 strain and variants of concern. Of five monoclonal antibodies that potently neutralized the WA1/2020 D614G strain, all retained neutralizing capacity against the B.1.617.2 variant, four also neutralized the B.1.1.7 variant, and only one, 2C08, also neutralized the B.1.351 and B.1.1.28 variants. 2C08 reduced lung viral load and morbidity in hamsters challenged with the WA1/2020 D614G, B.1.351, or B.1.617.2 strains. Clonal analysis identified 2C08-like public clonotypes among B cells responding to SARS-CoV-2 infection or vaccination in 41 out of 181 individuals. Thus, 2C08-like antibodies can be induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern.
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•2C08 is a germinal center B cell-derived anti-SARS-CoV-2 human monoclonal antibody•2C08 protects hamsters against challenge with B.1.351 and B.1.617.2 SARS-CoV-2 strains•2C08 recognizes a conserved epitope in the receptor-binding domain of SARS-CoV-2 spike•2C08-like clonotypes are induced after SARS-CoV-2 infection and vaccination in humans
SARS-CoV-2 variants with increased transmissibility are a public health threat. Schmitz et al. characterize 2C08, a human monoclonal antibody derived from a SARS-CoV-2 vaccine-induced germinal center B cell. 2C08 possesses a broad and potent neutralization capacity and protects hamsters against challenge with D614G, B.1.351, or B.1.617.2 strains. Public 2C08-like clones can be elicited by both SARS-CoV-2 infection and vaccination.
Despite the availability of licensed vaccines, influenza causes considerable morbidity and mortality worldwide. Current influenza vaccines elicit an immune response that primarily targets the head ...domain of the viral glycoprotein hemagglutinin (HA). Influenza viruses, however, readily evade this response by acquiring mutations in the head domain. While vaccines that target the more conserved HA stalk may circumvent this problem, low levels of antistalk antibodies are elicited by vaccination, possibly due to the poor accessibility of the stalk domain to B cell receptors. In this work, it is demonstrated that nanoparticles presenting HA in an inverted orientation generate tenfold higher antistalk antibody titers after a prime immunization and fivefold higher antistalk titers after a boost than nanoparticles displaying HA in its regular orientation. Moreover, nanoparticles presenting HA in an inverted orientation elicit a broader antistalk response that reduces mouse weight loss and improves survival after challenge to a greater extent than nanoparticles displaying HA in a regular orientation. Refocusing the antibody response toward conserved epitopes by controlling antigen orientation may enable the design of broadly protective nanovaccines targeting influenza viruses and other pathogens with pandemic potential.
The immune system generally targets the variable head domain of the influenza protein hemagglutinin (HA) rather than its conserved stalk domain, which results in a strain‐specific response. This phenomenon may be a result of HA orientation. In this work, nanoparticles that display HA in an inverted orientation are developed and found to elicit an enhanced stalk‐directed antibody response.
Initial exposure to a pathogen elicits an adaptive immune response to control and eradicate the threat. Interrogating the abundance and specificity of the naive B cell repertoire drives understanding ...of how to mount protective responses. Here, we isolated naive B cells from eight seronegative human donors targeting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor binding domain (RBD). Single-cell B cell receptor (BCR) sequencing identified diverse gene usage and no restriction on complementarity determining region length. A subset of recombinant antibodies produced by naive B cell precursors bound to SARS-CoV-2 RBD and engaged circulating variants including B.1.1.7, B.1.351, and B.1.617.2, as well as preemergent bat-derived coronaviruses RaTG13, SHC104, and WIV1. By structural characterization of a naive antibody in complex with SARS-CoV-2 spike, we identified a conserved mode of recognition shared with infection-induced antibodies. We found that representative naive antibodies could signal in a B cell activation assay, and by using directed evolution, we could select for a higher-affinity RBD interaction, conferred by a single amino acid change. The minimally mutated, affinity-matured antibodies also potently neutralized SARS-CoV-2. Understanding the SARS-CoV-2 RBD–specific naive repertoire may inform potential responses capable of recognizing future SARS-CoV-2 variants or emerging coronaviruses, enabling the development of pan-coronavirus vaccines aimed at engaging protective germline responses.
We present a systematic review and meta-analysis of the frequency, consequences, and treatment of stent loss during percutaneous coronary intervention (PCI).
Stent loss during PCI has received ...limited study.
We conducted a meta-analysis of 18 case series and 45 case reports published between 1991 and 2012 on stent loss during PCI. Data on the frequency of stent loss, treatment strategies, and clinical outcomes were collected.
A total of 1048 stents were lost in 968 PCIs. Stent loss occurred in 919 of 71,655 PCIs (1.3%; 95% confidence interval, 0.8%-2.8%). The incidence of stent loss in studies published before 2000, between 2000 and 2005, and after 2005 was 5%, 1%, and 0.3%, respectively (P<.001). Of the 1048 lost stents, 698 (66%) were successfully retrieved from the coronary circulation, 130 (12%) were deployed, 27 (3%) were crushed, and 28 (3%) were left untreated; treatment of 165 stents (16%) was not reported. A complication occurred in 171 patients (19%), of whom 98 (57%) had coronary artery bypass graft surgery, 31 (18%) myocardial infarction, 33 (19%) died, 10 (6%) had bleeding requiring transfusion, 5 (3%) had vascular access complications, and 1 patient (0.6%) had a cerebrovascular accident (some patients had more than one event).
The incidence of stent loss during PCI is low and has been decreasing. Although the lost stents were successfully retrieved in most cases, stent loss was associated with high rates of complications, such as coronary artery bypass graft surgery, myocardial infarction, and death.
Background
The management of bloating is unclear and its relationship with patients' well‐being and treatment satisfaction independent of other abdominal symptoms is uncharacterized. We evaluated the ...association of bloating with patient‐reported outcomes.
Methods
Thirty‐nine centers for functional gastrointestinal disorders joined the laxative inadequate relief survey. We enrolled 2203 consecutive outpatients with functional constipation (FC) or constipation‐predominant irritable bowel syndrome (IBS‐C) in two cross‐sectional waves. Both wave 1 and 2 included the SF‐12, the patient assessment of constipation‐symptoms (PAC‐SYM), and the treatment satisfaction questionnaire for medication (TSQM‐2). Wave 2 only included a global rating of change (GRC) scale to assess patients' assessment of efficacy concerning treatment switches occurred in the 3 months prior to the interview. Bloating in the abdomen was defined on the basis of PAC‐SYM item 3.
Key Results
The average age was 50.1 years (SD, 16.7) and 82.1% of patients were women. The prevalence of bloating was 91.6% (n = 1970). Bloating was associated with SF‐12 Physical Composite Score (p < 0.01), SF‐12 Mental Composite Score (p < 0.01), GRC (p < 0.01), Satisfaction with treatment effectiveness (p < 0.01), convenience of administration (p < 0.01), and side effects (p < 0.01) after adjustment for possible confounders.
Conclusions & Inferences
Our data suggest that patients regard bloating as a key element in assessing clinical changes and treatments' efficacy as this symptom exerts a strong influence on patient‐reported outcomes independent of possible confounders and other symptoms of constipation. Our data provide the rationale to investigate the efficacy and tolerability of new treatments specifically addressing this important, yet disregarded, patients' complain.
We sought to evaluate the association between bloating and quality of life, treatment satisfaction and treatment responsiveness among patients with constipation‐predominant irritable bowel syndrome and functional constipation. We enrolled 2203 patients in a two‐wave cross‐sectional survey: quality of life data obtained through self‐administered questionnaires were matched with reports of clinical examinations performed by gastroenterologist in 39 tertiary referral centers for the treatment of non‐organic constipation. We demonstrated that patients with non‐organic chronic constipation regard the symptom of bloating as a key element in assessing clinical changes and treatments' efficacy irrespective of the intensity of other symptoms.
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