Interventions against variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed. Stable and potent nanobodies (Nbs) that target the receptor binding domain (RBD) of ...SARS-CoV-2 spike are promising therapeutics. However, it is unknown if Nbs broadly neutralize circulating variants. We found that RBD Nbs are highly resistant to variants of concern (VOCs). High-resolution cryoelectron microscopy determination of eight Nb-bound structures reveals multiple potent neutralizing epitopes clustered into three classes: Class I targets ACE2-binding sites and disrupts host receptor binding. Class II binds highly conserved epitopes and retains activity against VOCs and RBD
. Cass III recognizes unique epitopes that are likely inaccessible to antibodies. Systematic comparisons of neutralizing antibodies and Nbs provided insights into how Nbs target the spike to achieve high-affinity and broadly neutralizing activity. Structure-function analysis of Nbs indicates a variety of antiviral mechanisms. Our study may guide the rational design of pan-coronavirus vaccines and therapeutics.
The COVID-19 pandemic urgently needs therapeutic and prophylactic interventions. Here, we report the rapid identification of SARS-CoV-2-neutralizing antibodies by high-throughput single-cell RNA and ...VDJ sequencing of antigen-enriched B cells from 60 convalescent patients. From 8,558 antigen-binding IgG1+ clonotypes, 14 potent neutralizing antibodies were identified, with the most potent one, BD-368-2, exhibiting an IC50 of 1.2 and 15 ng/mL against pseudotyped and authentic SARS-CoV-2, respectively. BD-368-2 also displayed strong therapeutic and prophylactic efficacy in SARS-CoV-2-infected hACE2-transgenic mice. Additionally, the 3.8 Å cryo-EM structure of a neutralizing antibody in complex with the spike-ectodomain trimer revealed the antibody’s epitope overlaps with the ACE2 binding site. Moreover, we demonstrated that SARS-CoV-2-neutralizing antibodies could be directly selected based on similarities of their predicted CDR3H structures to those of SARS-CoV-neutralizing antibodies. Altogether, we showed that human neutralizing antibodies could be efficiently discovered by high-throughput single B cell sequencing in response to pandemic infectious diseases.
Display omitted
•8,558 IgG1+ antigen-binding clonotypes were identified by high-throughput scRNA/VDJ-seq•14 potent SARS-CoV-2 neutralizing antibodies were found from 60 convalescent patients•BD-368-2 showed high therapeutic and prophylactic efficacy in SARS-CoV-2-infected mice•Neutralizing antibodies can be directly selected based on predicted CDR3H structures
Neutralizing antibodies, which could effectively block virus entry into host cells, are urgently needed for intervention against COVID-19. Using high-throughput single-cell RNA sequencing, Cao et al. identified fourteen potent neutralizing antibodies from 60 convalescent patients’ B cells. The most potent antibody, BD-368-2, exhibits high therapeutic and prophylactic efficacy in SARS-CoV-2-infected mice.
Current human immunodeficiency virus-1 (HIV-1) vaccines elicit strain-specific neutralizing antibodies. However, cross-reactive neutralizing antibodies arise in approximately 20% of HIV-1-infected ...individuals, and details of their generation could provide a blueprint for effective vaccination. Here we report the isolation, evolution and structure of a broadly neutralizing antibody from an African donor followed from the time of infection. The mature antibody, CH103, neutralized approximately 55% of HIV-1 isolates, and its co-crystal structure with the HIV-1 envelope protein gp120 revealed a new loop-based mechanism of CD4-binding-site recognition. Virus and antibody gene sequencing revealed concomitant virus evolution and antibody maturation. Notably, the unmutated common ancestor of the CH103 lineage avidly bound the transmitted/founder HIV-1 envelope glycoprotein, and evolution of antibody neutralization breadth was preceded by extensive viral diversification in and near the CH103 epitope. These data determine the viral and antibody evolution leading to induction of a lineage of HIV-1 broadly neutralizing antibodies, and provide insights into strategies to elicit similar antibodies by vaccination.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Structural principles underlying the composition of protective antiviral monoclonal antibody (mAb) cocktails are poorly defined. Here, we exploited antibody cooperativity to develop a therapeutic mAb ...cocktail against Ebola virus. We systematically analyzed the antibody repertoire in human survivors and identified a pair of potently neutralizing mAbs that cooperatively bound to the ebolavirus glycoprotein (GP). High-resolution structures revealed that in a two-antibody cocktail, molecular mimicry was a major feature of mAb-GP interactions. Broadly neutralizing mAb rEBOV-520 targeted a conserved epitope on the GP base region. mAb rEBOV-548 bound to a glycan cap epitope, possessed neutralizing and Fc-mediated effector function activities, and potentiated neutralization by rEBOV-520. Remodeling of the glycan cap structures by the cocktail enabled enhanced GP binding and virus neutralization. The cocktail demonstrated resistance to virus escape and protected non-human primates (NHPs) against Ebola virus disease. These data illuminate structural principles of antibody cooperativity with implications for development of antiviral immunotherapeutics.
Display omitted
•Human mAbs of two epitope specificities bind cooperatively to the ebolavirus GP•Cooperativity is mediated by a mAb that enhances binding to a vulnerable GP epitope•A two-mAb cocktail exhibits enhanced potency against heterologous ebolaviruses•Two 30 mg/kg doses of the cocktail fully protected non-human primates (NHPs) challenged with EBOV
Cooperative interactions of monoclonal antibodies (mAbs) with viral antigens are poorly understood. Gilchuk et al. perform structural and functional analysis of cooperativity in a cocktail of two human mAbs, recognizing major epitopes of ebolavirus glycoprotein (GP), and define cooperative binding of the GP as a mechanism for enhanced ebolavirus neutralization.
Respiratory syncytial virus (RSV) is an important causative agent of lower respiratory tract infections in infants and elderly individuals. Its fusion (F) protein is critical for virus infection. It ...is targeted by several investigational antivirals and by palivizumab, a humanized monoclonal antibody used prophylactically in infants considered at high risk of severe RSV disease. ALX-0171 is a trimeric Nanobody that binds the antigenic site II of RSV F protein with subnanomolar affinity. ALX-0171 demonstrated in vitro neutralization superior to that of palivizumab against prototypic RSV subtype A and B strains. Moreover, ALX-0171 completely blocked replication to below the limit of detection for 87% of the viruses tested, whereas palivizumab did so for 18% of the viruses tested at a fixed concentration. Importantly, ALX-0171 was highly effective in reducing both nasal and lung RSV titers when delivered prophylactically or therapeutically directly to the lungs of cotton rats. ALX-0171 represents a potent novel antiviral compound with significant potential to treat RSV-mediated disease.
Summary
Monoclonal antibodies have become a general modality in therapeutic development, and a variety of monoclonal antibodies targeting soluble antigens have been developed. However, even with ...infinite binding affinity to an antigen, a conventional antibody can bind to the antigen only once and results in an increase in total plasma antigen concentration in vivo. This antibody‐mediated antigen accumulation generally occurs because the clearance from circulation of an antibody–antigen complex is much slower than that of a free antigen. This limitation has recently been overcome by sweeping antibodies, which are capable of actively eliminating soluble antigens from circulation. A sweeping antibody incorporates two antibody engineering technologies: one is variable region engineering to enable the antibody to bind to an antigen in plasma and dissociate from the antigen in endosome (after which the antigen undergoes lysosomal degradation), and the other is constant region engineering to increase the cellular uptake of the antibody–antigen complex into endosome. By enhancing the elimination of soluble antigens from circulation, sweeping antibodies can therapeutically target soluble antigens that conventional antibodies cannot. This review discusses the features, engineering technologies, advantages, and applications of sweeping antibodies that target soluble antigens.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing monoclonal antibodies (mAbs) can reduce the risk of hospitalization from coronavirus disease 2019 (COVID-19) when ...administered early. However, SARS-CoV-2 variants of concern (VOCs) have negatively affected therapeutic use of some authorized mAbs. Using a high-throughput B cell screening pipeline, we isolated LY-CoV1404 (bebtelovimab), a highly potent SARS-CoV-2 spike glycoprotein receptor binding domain (RBD)-specific antibody. LY-CoV1404 potently neutralizes authentic SARS-CoV-2, B.1.1.7, B.1.351, and B.1.617.2. In pseudovirus neutralization studies, LY-CoV1404 potently neutralizes variants, including B.1.1.7, B.1.351, B.1.617.2, B.1.427/B.1.429, P.1, B.1.526, B.1.1.529, and the BA.2 subvariant. Structural analysis reveals that the contact residues of the LY-CoV1404 epitope are highly conserved, except for N439 and N501. The binding and neutralizing activity of LY-CoV1404 is unaffected by the most common mutations at these positions (N439K and N501Y). The broad and potent neutralization activity and the relatively conserved epitope suggest that LY-CoV1404 has the potential to be an effective therapeutic agent to treat all known variants.
Display omitted
•LY-CoV1404 potently neutralizes SARS-CoV-2 Omicron, BA.2 Omicron, and Delta variants•No loss of potency against currently circulating variants•Binding epitope on RBD of SARS-CoV-2 is rarely mutated based on current GISAID data•Breadth of neutralizing activity and potency supports clinical development
Westendorf et al. show that LY-CoV1404 is a potent SARS-CoV-2-binding antibody that neutralizes all known variants of concern and that its epitope is rarely mutated.
The recent emergence of SARS-CoV-2 variants of concern
and the recurrent spillovers of coronaviruses
into the human population highlight the need for broadly neutralizing antibodies that are not ...affected by the ongoing antigenic drift and that can prevent or treat future zoonotic infections. Here we describe a human monoclonal antibody designated S2X259, which recognizes a highly conserved cryptic epitope of the receptor-binding domain and cross-reacts with spikes from all clades of sarbecovirus. S2X259 broadly neutralizes spike-mediated cell entry of SARS-CoV-2, including variants of concern (B.1.1.7, B.1.351, P.1, and B.1.427/B.1.429), as well as a wide spectrum of human and potentially zoonotic sarbecoviruses through inhibition of angiotensin-converting enzyme 2 (ACE2) binding to the receptor-binding domain. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses an escape profile that is limited to a single substitution, G504D. We show that prophylactic and therapeutic administration of S2X259 protects Syrian hamsters (Mesocricetus auratus) against challenge with the prototypic SARS-CoV-2 and the B.1.351 variant of concern, which suggests that this monoclonal antibody is a promising candidate for the prevention and treatment of emergent variants and zoonotic infections. Our data reveal a key antigenic site that is targeted by broadly neutralizing antibodies and will guide the design of vaccines that are effective against all sarbecoviruses.
PDF
