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Motivation Protein solubility plays a vital role in pharmaceutical research and production yield. For a given protein, the extent of its solubility can represent the quality of its function, and is ultimately defined by its sequence. Thus, it is imperative to develop novel, highly accurate in silico sequence-based protein solubility predictors. In this work we propose, DeepSol, a novel Deep Learning-based protein solubility predictor. The backbone of our framework is a convolutional neural network that exploits k-mer structure and additional sequence and structural features extracted from the protein sequence. Results DeepSol outperformed all known sequence-based state-of-the-art solubility prediction methods and attained an accuracy of 0.77 and Matthew’s correlation coefficient of 0.55. The superior prediction accuracy of DeepSol allows to screen for sequences with enhanced production capacity and can more reliably predict solubility of novel proteins. Availability and implementation DeepSol’s best performing models and results are publicly deposited at https://doi.org/10.5281/zenodo.1162886 (Khurana and Mall, 2018). Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Motivation: Protein solubility can be a decisive factor in both research and production efficiency and in silico sequence-based predictors that can accurately estimate solubility outcomes are highly sought. Results: In this study, we present a novel approach termed PRotein SolubIlity Predictor (PaRSnIP), which uses a gradient boosting machine algorithm as well as an approximation of sequence and structural features of the protein of interest. Based on an independent test set, PaRSnIP outperformed other state-of-the-art sequence-based methods by more than 9% in accuracy and 0.17 in Matthew's correlation coefficient, with an overall accuracy of 74% and Matthew's correlation coefficient of 0.48. Additionally, PaRSnIP provides importance scores for all features used in training. We observed higher fractions of exposed residues to associate positively with protein solubility and tripeptide stretches with multiple histidines to associate negatively with solubility. The improved prediction accuracy of PaRSnIP should enable it to predict protein solubility with greater reliability and to screen for sequence variants with enhanced manufacturability. [ABSTRACT FROM AUTHOR]

Background: The post-genomic era with its wealth of sequences gave rise to a broad range of protein residueresidue contact detecting methods. Although various coevolution methods such as PSICOV, DCA and plmDCA provide correct contact predictions, they do not completely overlap. Hence, new approaches and improvements of existing methods are needed to motivate further development and progress in the field. We present a new contact detecting method, COUSCOus, by combining the best shrinkage approach, the empirical Bayes covariance estimator and GLasso. Results: Using the original PSICOV benchmark dataset, COUSCOus achieves mean accuracies of 0.74, 0.62 and 0.55 for the top L/10 predicted long, medium and short range contacts, respectively. In addition, COUSCOus attains mean areas under the precision-recall curves of 0.25, 0.29 and 0.30 for long, medium and short contacts and outperforms PSICOV. We also observed that COUSCOus outperforms PSICOV w.r.t. Matthew's correlation coefficient criterion on full list of residue contacts. Furthermore, COUSCOus achieves on average 10% more gain in prediction accuracy compared to PSICOV on an independent test set composed of CASP11 protein targets. Finally, we showed that when using a simple random forest meta-classifier, by combining contact detecting techniques and sequence derived features, PSICOV predictions should be replaced by the more accurate COUSCOus predictions. Conclusion: We conclude that the consideration of superior covariance shrinkage approaches will boost several research fields that apply the GLasso procedure, amongst the presented one of residue-residue contact prediction as well as fields such as gene network reconstruction. [ABSTRACT FROM AUTHOR]

The HIV-1 Env spike is the main protein complex that facilitates HIV-1 entry into CD4+ host cells. HIV-1 entry is a multistep process that is not yet completely understood. This process involves several protein-protein interactions between HIV-1 Env and a variety of host cell receptors along with many conformational changes within the spike. HIV-1 Env developed due to high mutation rates and plasticity escape strategies from immense immune pressure and entry inhibitors. We applied a coevolution and residue-residue contact detecting method to identify coevolution patterns within HIV-1 Env protein sequences representing all group M subtypes. We identified 424 coevolving residue pairs within HIV-1 Env. The majority of predicted pairs are residue-residue contacts and are proximal in 3D structure. Furthermore, many of the detected pairs have functional implications due to contributions in either CD4 or coreceptor binding, or variable loop, gp120-gp41, and interdomain interactions. This study provides a new dimension of information in HIV research. The identified residue couplings may not only be important in assisting gp120 and gp41 coordinate structure prediction, but also in designing new and effective entry inhibitors that incorporate mutation patterns of HIV-1 Env. [ABSTRACT FROM AUTHOR]

Ever since the case of the missing heritability was highlighted some years ago, scientists have been investigating various possible explanations for the issue. However, none of these explanations include non-chromosomal genetic information. Here we describe explicitly how chromosomal and non-chromosomal modifiers collectively influence the heritability of a trait, in this case, the growth rate of yeast. Our results show that the non-chromosomal contribution can be large, adding another dimension to the estimation of heritability. We also discovered, combining the strength of LASSO with model selection, that the interaction of chromosomal and non-chromosomal information is essential in describing phenotypes. [ABSTRACT FROM AUTHOR]

The epidemiology of HIV-1 in China has unique features that may have led to unique viral strains. We therefore tested the hypothesis that it is possible to find distinctive patterns in HIV-1 genomes sampled in China. Using a rule inference algorithm we could indeed extract from sequences of the third variable loop (V3) of HIV-1 gp120 a set of 14 signature patterns that with 89% accuracy distinguished Chinese from non-Chinese sequences. These patterns were found to be specific to HIV-1 subtype, i.e. sequences complying with pattern 1 were of subtype B, pattern 2 almost exclusively covered sequences of subtype 01_AE, etc. We then analyzed the first of these signature patterns in depth, namely that L and W at two V3 positions are specifically occurring in Chinese sequences of subtype B/B' (3% false positives). This pattern was found to be in agreement with the phylogeny of HIV-1 of subtype B inside and outside of China. We could neither reject nor convincingly confirm that the pattern is stabilized by immune escape. For further interpretation of the signature pattern we used the recently developed measure of Direct Information, and in this way discovered evidence for physical interactions between V2 and V3. We conclude by a discussion of limitations of signature patterns, and the applicability of the approach to other genomic regions and other countries. [ABSTRACT FROM AUTHOR]

Broadly neutralizing antibodies (bNAbs) targeting the HIV-1 envelope glycoprotein (Env) have promising utility in prevention and treatment of HIV-1 infection, and several are currently undergoing clinical trials. Due to the high sequence diversity and mutation rate of HIV-1, viral isolates are often resistant to specific bNAbs. Currently, resistant isolates are commonly identified by time-consuming and expensive in vitro neutralization assays. Here, we report machine learning classifiers that accurately predict resistance of HIV-1 isolates to 33 bNAbs. Notably, our classifiers achieved an overall prediction accuracy of 96% for 212 clinical isolates from patients enrolled in four different clinical trials. Moreover, use of gradient boosting machine – a tree-based machine learning method – enabled us to identify critical features, which had high accordance with epitope residues that distinguished between antibody resistance and sensitivity. The availability of an in silico antibody resistance predictor should facilitate informed decisions of antibody usage and sequence-based monitoring of viral escape in clinical settings. [ABSTRACT FROM AUTHOR]

Motivation Glycans play important roles in protein folding and cell–cell interactions—and, furthermore, glycosylation of protein antigens can dramatically impact immune responses. While there have been attempts to quantify the glycan shielding or coverage of a protein surface, none of the publicly available tools analyzes glycan shielding computationally at an atomistic level. Results Here, we developed an in silico approach, GLYCO (GLYcan COverage), to quantify the glycan shielding of a protein surface. The software provides insights into glycan-dense/sparse regions of the entire protein surface or a subset of the protein surface. GLYCO calculates glycan shielding from a single coordinate file or from multiple coordinate files, for instance, as obtained from molecular dynamics simulations or by nuclear magnetic resonance spectroscopy structure determination, enabling analysis of glycan dynamics. Overall, GLYCO provides fundamental insights into the glycan shielding of glycosylated proteins. Availability and implementation GLYCO is freely available at GitHub (https://github.com/myungjinlee/GLYCO). Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Motivation Biological experiments including proteomics and transcriptomics approaches often reveal sets of proteins that are most likely to be involved in a disease/disorder. To understand the functional nature of a set of proteins, it is important to capture the function of the proteins as a group, even in cases where function of individual proteins is not known. In this work, we propose a model that takes groups of proteins found to work together in a certain biological context, integrates them into functional relevance networks, and subsequently employs an iterative inference on graphical models to identify group functions of the proteins, which are then extended to predict function of individual proteins. Results The proposed algorithm, iterative group function prediction (iGFP), depicts proteins as a graph that represents functional relevance of proteins considering their known functional, proteomics and transcriptional features. Proteins in the graph will be clustered into groups by their mutual functional relevance, which is iteratively updated using a probabilistic graphical model, the conditional random field. iGFP showed robust accuracy even when substantial amount of GO annotations were missing. The perspective of 'group' function annotation opens up novel approaches for understanding functional nature of proteins in biological systems. Availability and implementation: http://kiharalab.org/iGFP/ Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Summary: CHOYCE is a web server for homology modelling of protein components and the fitting of those components into cryo electron microscopy (cryoEM) maps of their assemblies. It provides an interactive approach to improving the selection of models based on the quality of their fit into the EM map. [ABSTRACT FROM PUBLISHER]

Understanding maturation pathways of broadly neutralizing antibodies (bnAbs) against HIV‐1 can be highly informative for HIV‐1 vaccine development. A lineage of J038 bnAbs is now obtained from a long‐term SHIV‐infected macaque. J038 neutralizes 54% of global circulating HIV‐1 strains. Its binding induces a unique "up" conformation for one of the V2 loops in the trimeric envelope glycoprotein and is heavily dependent on glycan, which provides nearly half of the binding surface. Their unmutated common ancestor neutralizes the autologous virus. Continuous maturation enhances neutralization potency and breadth of J038 lineage antibodies via expanding antibody‐Env contact areas surrounding the core region contacted by germline‐encoded residues. Developmental details and recognition features of J038 lineage antibodies revealed here provide a new pathway for elicitation and maturation of V2‐targeting bnAbs. [ABSTRACT FROM AUTHOR]

Continuously evolving influenza viruses cause seasonal epidemics and pose global pandemic threats. Although viral neuraminidase (NA) is an effective drug and vaccine target, our understanding of the NA antigenic landscape still remains incomplete. Here, we describe NA-specific human antibodies that target the underside of the NA globular head domain, inhibit viral propagation of a wide range of human H3N2, swine-origin variant H3N2, and H2N2 viruses, and confer both pre- and post-exposure protection against lethal H3N2 infection in mice. Cryo-EM structures of two such antibodies in complex with NA reveal non-overlapping epitopes covering the underside of the NA head. These sites are highly conserved among N2 NAs yet inaccessible unless the NA head tilts or dissociates. Our findings help guide the development of effective countermeasures against ever-changing influenza viruses by identifying hidden conserved sites of vulnerability on the NA underside. [Display omitted] • Isolation of broadly cross-reactive and protective N2 NA-targeting human antibodies • Cryo-EM structures of two broadly cross-reactive antibodies in complex with N2 NA • Identification of conserved non-overlapping epitopes on the underside of NA head • Detection of antibodies to the NA underside epitopes in human convalescent samples Influenza neuraminidase (NA) is underappreciated as a vaccine target owing to its incomplete epitope landscape. Lederhofer et al. isolated human monoclonal antibodies to NA underside (i.e., dark side) epitopes with broad cross-reactivity across N2 subtype and protective efficacy in pre- and post-exposure settings, providing insights for NA-based vaccine design. [ABSTRACT FROM AUTHOR]

Vaccine-based elicitation of broadly neutralizing antibodies holds great promise for preventing HIV-1 transmission. However, the key biophysical markers of improved antibody recognition remain uncertain in the diverse landscape of potential antibody mutation pathways, and a more complete understanding of anti-HIV-1 fusion peptide (FP) antibody development will accelerate rational vaccine designs. Here we survey the mutational landscape of the vaccine-elicited anti-FP antibody, vFP16.02, to determine the genetic, structural, and functional features associated with antibody improvement or fitness. Using site-saturation mutagenesis and yeast display functional screening, we found that 1% of possible single mutations improved HIV-1 envelope trimer (Env) affinity, but generally comprised rare somatic hypermutations that may not arise frequently in vivo. We observed that many single mutations in the vFP16.02 Fab could enhance affinity >1,000-fold against soluble FP, although affinity improvements against the HIV-1 trimer were more measured and rare. The most potent variants enhanced affinity to both soluble FP and Env, had mutations concentrated in antibody framework regions, and achieved up to 37% neutralization breadth compared to 28% neutralization of the template antibody. Altered heavy- and light-chain interface angles and conformational dynamics, as well as reduced Fab thermal stability, were associated with improved HIV-1 neutralization breadth and potency. We also observed parallel sets of mutations that enhanced viral neutralization through similar structural mechanisms. These data provide a quantitative understanding of the mutational landscape for vaccine-elicited FP-directed broadly neutralizing antibody and demonstrate that numerous antigen-distal framework mutations can improve antibody function by enhancing affinity simultaneously toward HIV-1 Env and FP. [ABSTRACT FROM AUTHOR]

The vaccine elicitation of broadly neutralizing antibodies against HIV-1 is a long-sought goal. We previously reported the amino-terminal eight residues of the HIV-1-fusion peptide (FP8) – when conjugated to the carrier protein, keyhole limpet hemocyanin (KLH) – to be capable of inducing broadly neutralizing responses against HIV-1 in animal models. However, KLH is a multi-subunit particle derived from a natural source, and its manufacture as a clinical product remains a challenge. Here we report the preclinical development of recombinant tetanus toxoid heavy chain fragment (rTTHC) linked to FP8 (FP8-rTTHC) as a suitable FP-conjugate vaccine immunogen. We assessed 16 conjugates, made by coupling the 4 most prevalent FP8 sequences with 4 carrier proteins: the aforementioned KLH and rTTHC; the H. influenzae protein D (HiD); and the cross-reactive material from diphtheria toxin (CRM197). While each of the 16 FP8-carrier conjugates could elicit HIV-1-neutralizing responses, rTTHC conjugates induced higher FP-directed responses overall. A Sulfo-SIAB linker yielded superior results over an SM(PEG)2 linker but combinations of carriers, conjugation ratio of peptide to carrier, or choice of adjuvant (Adjuplex or Alum) did not significantly impact elicited FP-directed neutralizing responses in mice. Overall, SIAB-linked FP8-rTTHC appears to be a promising vaccine candidate for advancing to clinical assessment. [ABSTRACT FROM AUTHOR]

HIV-1 envelope (Env) trimers, stabilized in a prefusion-closed conformation, can elicit humoral responses capable of neutralizing HIV-1 strains closely matched in sequence to the immunizing strain. One strategy to increase elicited neutralization breadth involves vaccine priming of immune responses against a target site of vulnerability, followed by vaccine boosting of these responses with prefusion-closed Env trimers. This strategy has succeeded at the fusion peptide (FP) site of vulnerability in eliciting cross-clade neutralizing responses in standard vaccine-test animals. However, the breadth and potency of the elicited responses have been less than optimal. Here, we identify three mutations (3mut), Met302, Leu320, and Pro329, that stabilize the apex of the Env trimer in a prefusion-closed conformation and show antigenically, structurally, and immunogenically that combining 3mut with other approaches (e.g., repair and stabilize and glycine-helix breaking) yields well-behaved clade C-Env trimers capable of boosting the breadth of FPdirected responses. Crystal structures of these trimers confirmed prefusion-closed apexes stabilized by hydrophobic patches contributed by Met302 and Leu320, with Pro329 assuming canonically restricted dihedral angles. We substituted the N-terminal eight residues of FP (FP8, residues 512 to 519) of these trimers with the second most prevalent FP8 sequence (FP8v2, AVGLGAVF) and observed a 3mutstabilized consensus clade C-Env trimer with FP8v2 to boost the breadth elicited in guinea pigs of FP-directed responses induced by immunogens containing the most prevalent FP8 sequence (FP8v1, AVGIGAVF). Overall, 3mut can stabilize the Env trimer apex, and the resultant apex-stabilized Env trimers can be used to expand the neutralization breadth elicited against the FP site of vulnerability. IMPORTANCE A major hurdle to the development of an effective HIV-1 vaccine is the elicitation of serum responses capable of neutralizing circulating strains of HIV, which are extraordinarily diverse in sequence and often highly neutralization resistant. Recently, we showed how sera with 20 to 30% neutralization breadth could, nevertheless, be elicited in standard vaccine test animals by priming with the most prevalent N-terminal 8 residues of the HIV-1 fusion peptide (FP8), followed by boosting with a stabilized BG505-envelope (Env) trimer. Here, we show that subsequent boosting with a 3mut-apex-stabilized consensus C-Env trimer, modified to have the second most prevalent FP8 sequence, elicits higher neutralization breadth than that induced by continued boosting with the stabilized BG505-Env trimer. With increased neutralizing breadth elicited by boosting with a heterologous trimer containing the second most prevalent FP8 sequence, the fusion peptide-directed immune-focusing approach moves a step closer toward realizing an effective HIV-1 vaccine regimen. [ABSTRACT FROM AUTHOR]

Motivation X-ray crystallography has facilitated the majority of protein structures determined to date. Sequence-based predictors that can accurately estimate protein crystallization propensities would be highly beneficial to overcome the high expenditure, large attrition rate, and to reduce the trial-and-error settings required for crystallization. Results In this study, we present a novel model, BCrystal, which uses an optimized gradient boosting machine (XGBoost) on sequence, structural and physio-chemical features extracted from the proteins of interest. BCrystal also provides explanations, highlighting the most important features for the predicted crystallization propensity of an individual protein using the SHAP algorithm. On three independent test sets, BCrystal outperforms state-of-the-art sequence-based methods by more than 12.5% in accuracy, 18% in recall and 0.253 in Matthew's correlation coefficient, with an average accuracy of 93.7%, recall of 96.63% and Matthew's correlation coefficient of 0.868. For relative solvent accessibility of exposed residues, we observed higher values to associate positively with protein crystallizability and the number of disordered regions, fraction of coils and tripeptide stretches that contain multiple histidines associate negatively with crystallizability. The higher accuracy of BCrystal enables it to accurately screen for sequence variants with enhanced crystallizability. Availability and implementation Our BCrystal webserver is at https://machinelearning-protein.qcri.org/ and source code is available at https://github.com/raghvendra5688/BCrystal. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Following publication of the original article [1], the authors reported that one of the authors' names was processed incorrectly. In this Correction the incorrect and correct author name are shown. The original publication of this article has been corrected. [ABSTRACT FROM AUTHOR]

The vaccine elicitation of broadly neutralizing responses is a central goal of HIV research. Recently, we elicited cross-clade neutralizing responses against the N terminus of the fusion peptide (FP), a critical component of the HIV-entry machinery. While the consistency of the elicited cross-clade neutralizing responses was good in mice, it was poor in guinea pigs: after seven immunizations comprising either envelope (Env) trimer or FP coupled to a carrier, serum from only one of five animals could neutralize a majority of a cross-clade panel of 19 wild-type strains. Such a low response rate—only 20%—made increasing consistency an imperative. Here, we show that additional Env-trimer immunizations could boost broad FP-directed neutralizing responses in a majority of immunized animals. The first boost involved a heterologous Env trimer developed from the transmitted founder clade C strain of donor CH505, and the second boost involved a cocktail that combined the CH505 trimer with a trimer from the BG505 strain. After boosting, sera from three of five animals neutralized a majority of the 19-strain panel and serum from a fourth animal neutralized 8 strains. We demonstrate that cross-reactive serum neutralization targeted the FP by blocking neutralization with soluble fusion peptide. The FP competition revealed two categories of elicited responses: an autologous response to the BG505 strain of high potency (~10,000 ID50), which was not competed by soluble FP, and a heterologous response of lower potency, which was competed by soluble FP. While the autologous response could increase rapidly in response to Env-trimer boost, the heterologous neutralizing response increased more slowly. Overall, repetitive Env-trimer immunizations appeared to boost low titer FP-carrier primed responses to detectable levels, yielding cross-clade neutralization. The consistent trimer-boosted neutralizing responses described here add to accumulating evidence for the vaccine utility of the FP site of HIV vulnerability. [ABSTRACT FROM AUTHOR]

Background: Human tissues are invaluable resources for researchers worldwide. Biobanks are repositories of such human tissues and can have a strategic importance for genetic research, clinical care, and future discoveries and treatments. One of the aims of Qatar Biobank is to improve the understanding and treatment of common diseases afflicting Qatari population such as obesity and diabetes.Methods: In this study we apply a panorama of state-of-the-art statistical methods and machine learning algorithms to investigate associations and risk factors for diabetes and obesity on a sample of 1000 Qatari population.Results: Regarding diabetes, we identified pronounced associations and risk factors in Qatari population including magnesium, chloride, c-peptide of insulin, insulin, and uric acid. Similarly, for obesity, significant associations and risk factors include insulin, c-peptide of insulin, albumin, and uric acid. Moreover, our study has revealed interactions of hypomagnesemia with HDL-C, triglycerides, and free thyroxine.Conclusions: Our study strongly confirms known associations and risk factors associated with diabetes and obesity in Qatari population as previously found in other population studies in different parts of the world. Moreover, interactions of hypomagnesemia with other associations and risk factors merit further investigations. [ABSTRACT FROM AUTHOR]

Eliciting broadly neutralizing antibodies (bnAbs) targeting envelope (Env) is a major goal of HIV vaccine development, but cross-clade breadth from immunization has only sporadically been observed. Recently, Xu et al (2018) elicited cross-reactive neutralizing antibody responses in a variety of animal models using immunogens based on the epitope of bnAb VRC34.01. The VRC34.01 antibody, which was elicited by natural human infection, targets the N terminus of the Env fusion peptide, a critical component of the virus entry machinery. Here we precisely characterize the functional epitopes of VRC34.01 and two vaccine-elicited murine antibodies by mapping all single amino-acid mutations to the BG505 Env that affect viral neutralization. While escape from VRC34.01 occurred via mutations in both fusion peptide and distal interacting sites of the Env trimer, escape from the vaccine-elicited antibodies was mediated predominantly by mutations in the fusion peptide. Cryo-electron microscopy of four vaccine-elicited antibodies in complex with Env trimer revealed focused recognition of the fusion peptide and provided a structural basis for development of neutralization breadth. Together, these functional and structural data suggest that the breadth of vaccine-elicited antibodies targeting the fusion peptide can be enhanced by specific interactions with additional portions of Env. Thus, our complete maps of viral escape both delineate pathways of resistance to these fusion peptide-directed antibodies and provide a strategy to improve the breadth or potency of future vaccine-induced antibodies against Env’s fusion peptide. [ABSTRACT FROM AUTHOR]

Alphaviruses are RNA viruses that represent emerging public health threats. To identify protective antibodies, we immunized macaques with a mixture of western, eastern, and Venezuelan equine encephalitis virus-like particles (VLPs), a regimen that protects against aerosol challenge with all three viruses. Single- and triple-virus-specific antibodies were isolated, and we identified 21 unique binding groups. Cryo-EM structures revealed that broad VLP binding inversely correlated with sequence and conformational variability. One triple-specific antibody, SKT05, bound proximal to the fusion peptide and neutralized all three Env-pseudotyped encephalitic alphaviruses by using different symmetry elements for recognition across VLPs. Neutralization in other assays (e.g., chimeric Sindbis virus) yielded variable results. SKT05 bound backbone atoms of sequence-diverse residues, enabling broad recognition despite sequence variability; accordingly, SKT05 protected mice against Venezuelan equine encephalitis virus, chikungunya virus, and Ross River virus challenges. Thus, a single vaccine-elicited antibody can protect in vivo against a broad range of alphaviruses. [Display omitted] • Trivalent EEV VLP vaccine elicits antibodies with broad alphavirus activity • mAb SKT05 protects against arthritogenic and encephalitic alphavirus infection • Backbone contacts of sequence-diverse residues enable broad SKT05 recognition • Vaccinated macaques can be used to generate clinically relevant reagents Vaccine-elicited antibodies in non-human primates show a wide range of specificities against encephalitic and arthritogenic alphaviruses, extending to very broad recognition and providing insights into both antiviral immunity and vaccination strategies for alphavirus-driven diseases. [ABSTRACT FROM AUTHOR]

Motivation It is important to characterize individual relatedness in terms of familial relationships and underlying population structure in genome-wide association studies for correct downstream analysis. The characterization of individual relatedness becomes vital if the cohort is to be used as reference panel in other studies for association tests and for identifying ethnic diversities. In this paper, we propose a kinship visualization tool to detect cryptic relatedness between subjects. We utilize multi-dimensional scaling, bar charts, heat maps and node-link visualizations to enable analysis of relatedness information. Availability and implementation Available online as well as can be downloaded at http://shiny-vis.qcri.org/public/kinvis/. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Current influenza vaccines predominantly induce immunity to the hypervariable hemagglutinin (HA) head, requiring frequent vaccine reformulation. Conversely, the immunosubdominant yet conserved HA stem harbors a supersite that is targeted by broadly neutralizing antibodies (bnAbs), representing a prime target for universal vaccines. Here, we showed that the co-immunization of two HA stem immunogens derived from group 1 and 2 influenza A viruses elicits cross-group protective immunity and neutralizing antibody responses in mice, ferrets, and nonhuman primates (NHPs). Immunized mice were protected from multiple group 1 and 2 viruses, and all animal models showed broad serum-neutralizing activity. A bnAb isolated from an immunized NHP broadly neutralized and protected against diverse viruses, including H5N1 and H7N9. Genetic and structural analyses revealed strong homology between macaque and human bnAbs, illustrating common biophysical constraints for acquiring cross-group specificity. Vaccine elicitation of stem-directed cross-group-protective immunity represents a step toward the development of broadly protective influenza vaccines. [Display omitted] • Broad group 2 protective immunity was induced by H10-based group 2 HA stem immunogen • Co-immunization with group 1 and 2 HA stem immunogens elicits cross-protective antibodies • A bnAb isolated from an immunized NHP neutralizes both group 1 and 2 influenza A viruses • A common mode of HA recognition via the D H gene-encoded motif among NHP and human bnAbs Current vaccine-induced influenza immunity targets the hypervariable HA head, requiring frequent vaccine reformulation. Moin et al. show that co-immunization with HA stem immunogens of group 1 and group 2 influenza A viruses broadly elicits cross-protective antibodies in animals and leads to the discovery of a cross-group protective monoclonal antibody in a macaque, offering a blueprint for broadly protective influenza vaccines. [ABSTRACT FROM AUTHOR]

Immunization with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike elicits diverse antibodies, but it is unclear if any of the antibodies can neutralize broadly against other beta-coronaviruses. Here, we report antibody WS6 from a mouse immunized with mRNA encoding the SARS-CoV-2 spike. WS6 bound diverse beta-coronavirus spikes and neutralized SARS-CoV-2 variants, SARS-CoV, and related sarbecoviruses. Epitope mapping revealed WS6 to target a region in the S2 subunit, which was conserved among SARS-CoV-2, Middle East respiratory syndrome (MERS)-CoV, and hCoV-OC43. The crystal structure at 2 Å resolution of WS6 revealed recognition to center on a conserved S2 helix, which was occluded in both pre- and post-fusion spike conformations. Structural and neutralization analyses indicated WS6 to neutralize by inhibiting fusion and post-viral attachment. Comparison of WS6 with other recently identified antibodies that broadly neutralize beta-coronaviruses indicated a stem-helical supersite—centered on hydrophobic residues Phe1148, Leu1152, Tyr1155, and Phe1156—to be a promising target for vaccine design. [Display omitted] • Antibody WS6 from SARS-CoV-2 spike-immunized mice binds diverse beta-CoV spikes • WS6 neutralizes SARS-CoV-2 variants, SARS-CoV, and related sarbecoviruses • Crystal structure of WS6 with a conserved S2 peptide reveals a helical epitope • WS6 epitope belongs to an S2 supersite recognized by diverse antibodies Shi et al. identified a broad beta-coronavirus neutralizing antibody from mice immunized with mRNA encoding the SARS-CoV-2 spike. This antibody targets an S2 supersite comprising a hydrophobic cluster spanning three helical turns, which are conserved among beta-coronaviruses. This S2 supersite appears to be a good target for broad beta-coronavirus vaccines. [ABSTRACT FROM AUTHOR]

Several influenza antibodies with broad group 2 neutralization have recently been isolated. Here, we analyze the structure, class, and binding of one of these antibodies from an H7N9 vaccine trial, 315-19-1D12. The cryo-EM structure of 315-19-1D12 Fab in complex with the hemagglutinin (HA) trimer revealed the antibody to recognize the helix A region of the HA stem, at the supersite of vulnerability recognized by group 1-specific and by cross-group-neutralizing antibodies. 315-19-1D12 was derived from HV1-2 and KV2-28 genes and appeared to form a new antibody class. Bioinformatic analysis indicated its group 2 neutralization specificity to be a consequence of four key residue positions. We specifically tested the impact of the group 1-specific N33 glycan, which decreased but did not abolish group 2 binding of 315-19-1D12. Overall, this study highlights the recognition of a broad group 2-neutralizing antibody, revealing unexpected diversity in neutralization specificity for antibodies that recognize the HA stem supersite. [Display omitted] • Structure of 1D12 in complex with HA at 2.8 Å reveals an epitope in the HA stem • 1D12 epitope differs from that of other known broad group 2-neutralizing antibodies • 1D12 derives from IGHV1-2 and IGKV2-28 and forms another antibody class • HA residues 33, 278, 366, and 377 delineate neutralization specificity of 1D12 Influenza hemagglutinin stem-targeting antibodies can neutralize group 1 and/or 2 viruses. Cheung et al. isolate a broad group 2-neutralizing antibody, 1D12, from an H7N9 vaccine trial. Its epitope overlaps better with group 1 and cross-group epitopes than with previously described group 2 epitopes, revealing unexpected differences in neutralization specificity versus epitope. [ABSTRACT FROM AUTHOR]

Nanobodies can achieve remarkable neutralization of genetically diverse pathogens, including HIV-1. To gain insight into their recognition, we determined crystal structures of four llama nanobodies (J3, A12, C8, and D7), all of which targeted the CD4-binding site, in complex with the HIV-1 envelope (Env) gp120 core, and determined a cryoelectron microscopy (cryo-EM) structure of J3 with the Env trimer. Crystal and cryo-EM structures of J3 complexes revealed this nanobody to mimic binding to the prefusion-closed trimer for the primary site of CD4 recognition as well as a secondary quaternary site. In contrast, crystal structures of A12, C8, and D7 with gp120 revealed epitopes that included portions of the gp120 inner domain, inaccessible on the prefusion-closed trimer. Overall, these structures explain the broad and potent neutralization of J3 and limited neutralization of A12, C8, and D7, which utilized binding modes incompatible with the neutralization-targeted prefusion-closed conformation of Env. [Display omitted] • Crystal and cryo-EM structures show basis for broad neutralization by nanobody J3 • J3 recognizes a quaternary site on Env trimer, mimicking initial CD4 attachment • A12, C8, and D7 binding modes are incompatible with the prefusion-closed Env trimer • A12, C8, and D7 neutralize, with limited breadth, only a common set of HIV-1 strains Nanobodies are potential therapeutic agents against diverse pathogens. Zhou et al. determine the structures of four llama nanobodies in complex with HIV envelope trimer or gp120 core. The structures show that the broadly neutralizing nanobody J3 recognizes the prefusion-closed trimer, whereas the other, less broad nanobodies recognize only the open conformation. [ABSTRACT FROM AUTHOR]

Antibody 10E8 is capable of effectively neutralizing HIV through its recognition of the membrane-proximal external region (MPER), and a suitably optimized version of 10E8 might have utility in HIV therapy and prophylaxis. However, 10E8 displays a three-peak profile on size-exclusion chromatography (SEC), complicating its manufacture. Here we show cis-trans conformational isomerization of the Tyr-Pro-Pro (YPP) motif in the heavy chain 3rd complementarity-determining region (CDR H3) of antibody 10E8 to be the mechanistic basis of its multipeak behavior. We observed 10E8 to undergo slow conformational isomerization and delineate a mechanistic explanation for effective comodifiers that were able to resolve its SEC heterogeneity and to allow an evaluation of the critical quality attribute of aggregation. We determined crystal structures of single and double alanine mutants of a key di-proline motif and of a light chain variant, revealing alternative conformations of the CDR H3. We also replicated both multi-peak and delayed SEC behavior with MPER-antibodies 4E10 and VRC42, by introducing a Tyr-Pro (YP) motif into their CDR H3s. Our results show how a conformationally dynamic CDR H3 can provide the requisite structural plasticity needed for a highly hydrophobic paratope to recognize its membrane-proximal epitope. [ABSTRACT FROM AUTHOR]

Summary Over the past decade, structures have been determined for broadly neutralizing antibodies that recognize all major exposed surfaces of the prefusion-closed HIV-1-envelope (Env) trimer. To understand this recognition and its implications, we analyzed 206 antibody-HIV-1 Env structures from the Protein Data Bank with resolution suitable to define interaction chemistries and measured antibody neutralization on a 208-strain panel. Those with >25% breadth segregated into almost two dozen classes based on ontogeny and recognition and into six epitope categories based on recognized Env residues. For paratope, the number of protruding loops and level of somatic hypermutation were significantly higher for broad HIV-1 neutralizing antibodies than for a comparison set of non-HIV-1 antibodies (p < 0.0001). For epitope, the number of independent sequence segments was higher (p < 0.0001), as well as the glycan component surface area (p = 0.0005). The unusual characteristics of epitope and paratope delineated here are likely to reflect respectively virus-immune evasion and antibody-recognition solutions that allow effective neutralization of HIV-1. Graphical Abstract Highlights • Classification of HIV-1 antibodies into six categories based on recognized epitope • Delineation of underlying relationships between neutralization and epitope/paratope • Identification of epitope/paratope features specific to HIV-1 antibodies • Evaluation of epitopes for ease of antibody elicitation by vaccination Antibody-envelope structures have been determined that recognize all major exposed surfaces of the HIV-1 envelope trimer. Chuang et al. classify these structures to delineate overall categories and to reveal underlying relationships between neutralization and epitope/paratope, specific features of HIV-1 broadly neutralizing antibodies, and sites of vulnerability most suitable for vaccine design. [ABSTRACT FROM AUTHOR]

Summary Virtually the entire surface of the HIV-1-envelope trimer is recognized by neutralizing antibodies, except for a highly glycosylated region at the center of the “silent face” on the gp120 subunit. From an HIV-1-infected donor, #74, we identified antibody VRC-PG05, which neutralized 27% of HIV-1 strains. The crystal structure of the antigen-binding fragment of VRC-PG05 in complex with gp120 revealed an epitope comprised primarily of N -linked glycans from N262, N295, and N448 at the silent face center. Somatic hypermutation occurred preferentially at antibody residues that interacted with these glycans, suggesting somatic development of glycan recognition. Resistance to VRC-PG05 in donor #74 involved shifting of glycan-N448 to N446 or mutation of glycan-proximal residue E293. HIV-1 neutralization can thus be achieved at the silent face center by glycan-recognizing antibody; along with other known epitopes, the VRC-PG05 epitope completes coverage by neutralizing antibody of all major exposed regions of the prefusion closed trimer. [ABSTRACT FROM AUTHOR]