RESUMO
Congenital Zika virus (ZIKV) infection results in neurodevelopmental deficits in up to 14% of infants born to ZIKV-infected mothers. Neutralizing antibodies are a critical component of protective immunity. Here, we demonstrate that plasma IgM contributes to ZIKV immunity in pregnancy, mediating neutralization up to 3 months post-symptoms. From a ZIKV-infected pregnant woman, we isolated a pentameric ZIKV-specific IgM (DH1017.IgM) that exhibited ultrapotent ZIKV neutralization dependent on the IgM isotype. DH1017.IgM targets an envelope dimer epitope within domain II. The epitope arrangement on the virion is compatible with concurrent engagement of all ten antigen-binding sites of DH1017.IgM, a solution not available to IgG. DH1017.IgM protected mice against viremia upon lethal ZIKV challenge more efficiently than when expressed as an IgG. Our findings identify a role for antibodies of the IgM isotype in protection against ZIKV and posit DH1017.IgM as a safe and effective candidate immunotherapeutic, particularly during pregnancy.
Assuntos
Imunoglobulina M , Gravidez , Infecção por Zika virus , Zika virus , Animais , Feminino , Camundongos , Gravidez/imunologia , Anticorpos Neutralizantes , Anticorpos Antivirais , Epitopos , Testes de Neutralização , Infecção por Zika virus/imunologia , Imunoglobulina M/imunologia , Imunoglobulina M/isolamento & purificaçãoRESUMO
The Omicron lineage of SARS-CoV-2, which was first described in November 2021, spread rapidly to become globally dominant and has split into a number of sublineages. BA.1 dominated the initial wave but has been replaced by BA.2 in many countries. Recent sequencing from South Africa's Gauteng region uncovered two new sublineages, BA.4 and BA.5, which are taking over locally, driving a new wave. BA.4 and BA.5 contain identical spike sequences, and although closely related to BA.2, they contain further mutations in the receptor-binding domain of their spikes. Here, we study the neutralization of BA.4/5 using a range of vaccine and naturally immune serum and panels of monoclonal antibodies. BA.4/5 shows reduced neutralization by the serum from individuals vaccinated with triple doses of AstraZeneca or Pfizer vaccine compared with BA.1 and BA.2. Furthermore, using the serum from BA.1 vaccine breakthrough infections, there are, likewise, significant reductions in the neutralization of BA.4/5, raising the possibility of repeat Omicron infections.
Assuntos
COVID-19 , Vacinas Virais , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Humanos , Testes de Neutralização , SARS-CoV-2/genética , África do SulRESUMO
HIV-1 Env mediates viral entry into host cells and is the sole target for neutralizing antibodies. However, Env structure and organization in its native virion context has eluded detailed characterization. Here, we used cryo-electron tomography to analyze Env in mature and immature HIV-1 particles. Immature particles showed distinct Env positioning relative to the underlying Gag lattice, providing insights into long-standing questions about Env incorporation. A 9.1-Å sub-tomogram-averaged reconstruction of virion-bound Env in conjunction with structural mass spectrometry revealed unexpected features, including a variable central core of the gp41 subunit, heterogeneous glycosylation between protomers, and a flexible stalk that allows Env tilting and variable exposure of neutralizing epitopes. Together, our results provide an integrative understanding of HIV assembly and structural variation in Env antigen presentation.
Assuntos
Microscopia Crioeletrônica , Tomografia com Microscopia Eletrônica , Vírion/ultraestrutura , Produtos do Gene env do Vírus da Imunodeficiência Humana/ultraestrutura , Produtos do Gene gag do Vírus da Imunodeficiência Humana/ultraestrutura , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/farmacologia , Sequência de Aminoácidos , Dissulfetos/farmacologia , Epitopos/química , Células HEK293 , Proteína gp41 do Envelope de HIV/química , Humanos , Espectrometria de Massa com Troca Hidrogênio-Deutério , Modelos Moleculares , Testes de Neutralização , Peptídeos/química , Polissacarídeos/química , Domínios Proteicos , Estrutura Secundária de Proteína , Subunidades Proteicas/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/químicaRESUMO
Highly transmissible Omicron variants of SARS-CoV-2 currently dominate globally. Here, we compare neutralization of Omicron BA.1, BA.1.1, and BA.2. BA.2 RBD has slightly higher ACE2 affinity than BA.1 and slightly reduced neutralization by vaccine serum, possibly associated with its increased transmissibility. Neutralization differences between sub-lineages for mAbs (including therapeutics) mostly arise from variation in residues bordering the ACE2 binding site; however, more distant mutations S371F (BA.2) and R346K (BA.1.1) markedly reduce neutralization by therapeutic antibody Vir-S309. In-depth structure-and-function analyses of 27 potent RBD-binding mAbs isolated from vaccinated volunteers following breakthrough Omicron-BA.1 infection reveals that they are focused in two main clusters within the RBD, with potent right-shoulder antibodies showing increased prevalence. Selection and somatic maturation have optimized antibody potency in less-mutated epitopes and recovered potency in highly mutated epitopes. All 27 mAbs potently neutralize early pandemic strains, and many show broad reactivity with variants of concern.
Assuntos
Anticorpos Monoclonais , Vacinas contra COVID-19/imunologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Anticorpos Antivirais , COVID-19 , Vacinas contra COVID-19/administração & dosagem , Epitopos , Humanos , Testes de Neutralização , SARS-CoV-2/classificação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/químicaRESUMO
The SARS-CoV-2 Omicron variant with increased fitness is spreading rapidly worldwide. Analysis of cryo-EM structures of the spike (S) from Omicron reveals amino acid substitutions forging interactions that stably maintain an active conformation for receptor recognition. The relatively more compact domain organization confers improved stability and enhances attachment but compromises the efficiency of the viral fusion step. Alterations in local conformation, charge, and hydrophobic microenvironments underpin the modulation of the epitopes such that they are not recognized by most NTD- and RBD-antibodies, facilitating viral immune escape. Structure of the Omicron S bound with human ACE2, together with the analysis of sequence conservation in ACE2 binding region of 25 sarbecovirus members, as well as heatmaps of the immunogenic sites and their corresponding mutational frequencies, sheds light on conserved and structurally restrained regions that can be used for the development of broad-spectrum vaccines and therapeutics.
Assuntos
Evasão da Resposta Imune/fisiologia , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/química , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Antivirais/imunologia , Sítios de Ligação , COVID-19/imunologia , COVID-19/patologia , COVID-19/virologia , Microscopia Crioeletrônica , Humanos , Mutagênese Sítio-Dirigida , Testes de Neutralização , Ligação Proteica , Domínios Proteicos/imunologia , Estrutura Quaternária de Proteína , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Ressonância de Plasmônio de Superfície , Ligação ViralRESUMO
The emerging SARS-CoV-2 variants of concern (VOCs) threaten the effectiveness of current COVID-19 vaccines administered intramuscularly and designed to only target the spike protein. There is a pressing need to develop next-generation vaccine strategies for broader and long-lasting protection. Using adenoviral vectors (Ad) of human and chimpanzee origin, we evaluated Ad-vectored trivalent COVID-19 vaccines expressing spike-1, nucleocapsid, and RdRp antigens in murine models. We show that single-dose intranasal immunization, particularly with chimpanzee Ad-vectored vaccine, is superior to intramuscular immunization in induction of the tripartite protective immunity consisting of local and systemic antibody responses, mucosal tissue-resident memory T cells and mucosal trained innate immunity. We further show that intranasal immunization provides protection against both the ancestral SARS-CoV-2 and two VOC, B.1.1.7 and B.1.351. Our findings indicate that respiratory mucosal delivery of Ad-vectored multivalent vaccine represents an effective next-generation COVID-19 vaccine strategy to induce all-around mucosal immunity against current and future VOC.
Assuntos
Vacinas contra COVID-19/administração & dosagem , COVID-19/prevenção & controle , Imunidade nas Mucosas , Administração Intranasal , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , COVID-19/virologia , Vacinas contra COVID-19/imunologia , Citocinas/sangue , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Vetores Genéticos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Testes de Neutralização , Nucleocapsídeo/genética , Nucleocapsídeo/imunologia , Nucleocapsídeo/metabolismo , Pan troglodytes , SARS-CoV-2/genética , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
Crimean-Congo hemorrhagic fever virus (CCHFV) is a World Health Organization priority pathogen. CCHFV infections cause a highly lethal hemorrhagic fever for which specific treatments and vaccines are urgently needed. Here, we characterize the human immune response to natural CCHFV infection to identify potent neutralizing monoclonal antibodies (nAbs) targeting the viral glycoprotein. Competition experiments showed that these nAbs bind six distinct antigenic sites in the Gc subunit. These sites were further delineated through mutagenesis and mapped onto a prefusion model of Gc. Pairwise screening identified combinations of non-competing nAbs that afford synergistic neutralization. Further enhancements in neutralization breadth and potency were attained by physically linking variable domains of synergistic nAb pairs through bispecific antibody (bsAb) engineering. Although multiple nAbs protected mice from lethal CCHFV challenge in pre- or post-exposure prophylactic settings, only a single bsAb, DVD-121-801, afforded therapeutic protection. DVD-121-801 is a promising candidate suitable for clinical development as a CCHFV therapeutic.
Assuntos
Anticorpos Neutralizantes/imunologia , Febre Hemorrágica da Crimeia/imunologia , Sobreviventes , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Antígenos Virais/metabolismo , Fenômenos Biofísicos , Chlorocebus aethiops , Mapeamento de Epitopos , Epitopos/metabolismo , Feminino , Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Febre Hemorrágica da Crimeia/prevenção & controle , Humanos , Imunoglobulina G/metabolismo , Masculino , Camundongos , Testes de Neutralização , Ligação Proteica , Engenharia de Proteínas , Proteínas Recombinantes/imunologia , Células Vero , Proteínas Virais/químicaRESUMO
The global spread of SARS-CoV-2/COVID-19 is devastating health systems and economies worldwide. Recombinant or vaccine-induced neutralizing antibodies are used to combat the COVID-19 pandemic. However, the recently emerged SARS-CoV-2 variants B.1.1.7 (UK), B.1.351 (South Africa), and P.1 (Brazil) harbor mutations in the viral spike (S) protein that may alter virus-host cell interactions and confer resistance to inhibitors and antibodies. Here, using pseudoparticles, we show that entry of all variants into human cells is susceptible to blockade by the entry inhibitors soluble ACE2, Camostat, EK-1, and EK-1-C4. In contrast, entry of the B.1.351 and P.1 variant was partially (Casirivimab) or fully (Bamlanivimab) resistant to antibodies used for COVID-19 treatment. Moreover, entry of these variants was less efficiently inhibited by plasma from convalescent COVID-19 patients and sera from BNT162b2-vaccinated individuals. These results suggest that SARS-CoV-2 may escape neutralizing antibody responses, which has important implications for efforts to contain the pandemic.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , SARS-CoV-2/imunologia , Animais , COVID-19/imunologia , COVID-19/terapia , COVID-19/virologia , Linhagem Celular , Farmacorresistência Viral , Humanos , Imunização Passiva , Cinética , Fusão de Membrana , Modelos Moleculares , Testes de Neutralização , Serina Endopeptidases/metabolismo , Solubilidade , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinação , Internalização do Vírus , Soroterapia para COVID-19RESUMO
Monoclonal antibodies against SARS-CoV-2 are a clinically validated therapeutic option against COVID-19. Because rapidly emerging virus mutants are becoming the next major concern in the fight against the global pandemic, it is imperative that these therapeutic treatments provide coverage against circulating variants and do not contribute to development of treatment-induced emergent resistance. To this end, we investigated the sequence diversity of the spike protein and monitored emergence of virus variants in SARS-COV-2 isolates found in COVID-19 patients treated with the two-antibody combination REGEN-COV, as well as in preclinical in vitro studies using single, dual, or triple antibody combinations, and in hamster in vivo studies using REGEN-COV or single monoclonal antibody treatments. Our study demonstrates that the combination of non-competing antibodies in REGEN-COV provides protection against all current SARS-CoV-2 variants of concern/interest and also protects against emergence of new variants and their potential seeding into the population in a clinical setting.
Assuntos
Anticorpos Monoclonais/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Mutação/genética , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Animais , COVID-19/virologia , Chlorocebus aethiops , Cricetinae , Microscopia Crioeletrônica , Hospitalização , Humanos , Pulmão/patologia , Pulmão/virologia , Masculino , Testes de Neutralização , Células Vero , Carga ViralRESUMO
Most human monoclonal antibodies (mAbs) neutralizing SARS-CoV-2 recognize the spike (S) protein receptor-binding domain and block virus interactions with the cellular receptor angiotensin-converting enzyme 2. We describe a panel of human mAbs binding to diverse epitopes on the N-terminal domain (NTD) of S protein from SARS-CoV-2 convalescent donors and found a minority of these possessed neutralizing activity. Two mAbs (COV2-2676 and COV2-2489) inhibited infection of authentic SARS-CoV-2 and recombinant VSV/SARS-CoV-2 viruses. We mapped their binding epitopes by alanine-scanning mutagenesis and selection of functional SARS-CoV-2 S neutralization escape variants. Mechanistic studies showed that these antibodies neutralize in part by inhibiting a post-attachment step in the infection cycle. COV2-2676 and COV2-2489 offered protection either as prophylaxis or therapy, and Fc effector functions were required for optimal protection. Thus, natural infection induces a subset of potent NTD-specific mAbs that leverage neutralizing and Fc-mediated activities to protect against SARS-CoV-2 infection using multiple functional attributes.
Assuntos
Anticorpos Monoclonais/farmacologia , Anticorpos Neutralizantes/farmacologia , Substâncias Protetoras/farmacologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Animais , Ligação Competitiva , COVID-19/imunologia , COVID-19/virologia , Quimiocinas/metabolismo , Chlorocebus aethiops , Células HEK293 , Humanos , Fragmentos Fab das Imunoglobulinas/metabolismo , Imunoglobulina G/metabolismo , Pulmão/metabolismo , Camundongos Endogâmicos C57BL , Modelos Moleculares , Mutagênese/genética , Testes de Neutralização , Domínios Proteicos , Células VeroRESUMO
The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design.
Assuntos
Antígenos Virais/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/virologia , Cricetinae , Mapeamento de Epitopos , Variação Genética , Modelos Moleculares , Mutação/genética , Testes de Neutralização , Domínios Proteicos , RNA Viral/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/ultraestruturaRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has undergone progressive change, with variants conferring advantage rapidly becoming dominant lineages, e.g., B.1.617. With apparent increased transmissibility, variant B.1.617.2 has contributed to the current wave of infection ravaging the Indian subcontinent and has been designated a variant of concern in the United Kingdom. Here we study the ability of monoclonal antibodies and convalescent and vaccine sera to neutralize B.1.617.1 and B.1.617.2, complement this with structural analyses of Fab/receptor binding domain (RBD) complexes, and map the antigenic space of current variants. Neutralization of both viruses is reduced compared with ancestral Wuhan-related strains, but there is no evidence of widespread antibody escape as seen with B.1.351. However, B.1.351 and P.1 sera showed markedly more reduction in neutralization of B.1.617.2, suggesting that individuals infected previously by these variants may be more susceptible to reinfection by B.1.617.2. This observation provides important new insights for immunization policy with future variant vaccines in non-immune populations.
Assuntos
Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Complexo Antígeno-Anticorpo/química , COVID-19/patologia , COVID-19/terapia , COVID-19/virologia , Vacinas contra COVID-19/administração & dosagem , Chlorocebus aethiops , Cristalografia por Raios X , Humanos , Imunização Passiva , Testes de Neutralização , Domínios Proteicos/imunologia , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Células Vero , Soroterapia para COVID-19RESUMO
The race to produce vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began when the first sequence was published, and this forms the basis for vaccines currently deployed globally. Independent lineages of SARS-CoV-2 have recently been reported: UK, B.1.1.7; South Africa, B.1.351; and Brazil, P.1. These variants have multiple changes in the immunodominant spike protein that facilitates viral cell entry via the angiotensin-converting enzyme-2 (ACE2) receptor. Mutations in the receptor recognition site on the spike are of great concern for their potential for immune escape. Here, we describe a structure-function analysis of B.1.351 using a large cohort of convalescent and vaccinee serum samples. The receptor-binding domain mutations provide tighter ACE2 binding and widespread escape from monoclonal antibody neutralization largely driven by E484K, although K417N and N501Y act together against some important antibody classes. In a number of cases, it would appear that convalescent and some vaccine serum offers limited protection against this variant.
Assuntos
Vacinas contra COVID-19/sangue , Vacinas contra COVID-19/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/imunologia , COVID-19/imunologia , COVID-19/terapia , COVID-19/virologia , Chlorocebus aethiops , Ensaios Clínicos como Assunto , Células HEK293 , Humanos , Imunização Passiva , Modelos Moleculares , Mutação/genética , Testes de Neutralização , Ligação Proteica , SARS-CoV-2/química , SARS-CoV-2/genética , Células Vero , Soroterapia para COVID-19RESUMO
A fascinating aspect of viral evolution relates to the ability of viruses to escape the adaptive immune response. The widely held view has been that the great variability of viral glycoproteins would be an absolute obstacle to the development of antibody-based therapies or vaccines that could confer broad and long-lasting protection. In the past five years, new approaches have been developed to interrogate human memory B cells and plasma cells with high efficiency and to isolate several broadly neutralizing antiviral antibodies against highly variable pathogens such as HIV-1 and influenza virus. These antibodies not only provide new tools for prophylaxis and therapy for viral diseases but also identify conserved epitopes that may be used to design new vaccines capable of conferring broader protection.
Assuntos
Anticorpos Antivirais/fisiologia , Testes de Neutralização/métodos , Animais , Anticorpos Antivirais/uso terapêutico , Anticorpos Anti-HIV/uso terapêutico , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , Humanos , Imunização Passiva/métodos , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Terapia de Alvo Molecular/métodosRESUMO
Eastern equine encephalitis virus (EEEV) is one of the most virulent viruses endemic to North America. No licensed vaccines or antiviral therapeutics are available to combat this infection, which has recently shown an increase in human cases. Here, we characterize human monoclonal antibodies (mAbs) isolated from a survivor of natural EEEV infection with potent (<20 pM) inhibitory activity of EEEV. Cryo-electron microscopy reconstructions of two highly neutralizing mAbs, EEEV-33 and EEEV-143, were solved in complex with chimeric Sindbis/EEEV virions to 7.2 Å and 8.3 Å, respectively. The mAbs recognize two distinct antigenic sites that are critical for inhibiting viral entry into cells. EEEV-33 and EEEV-143 protect against disease following stringent lethal aerosol challenge of mice with highly pathogenic EEEV. These studies provide insight into the molecular basis for the neutralizing human antibody response against EEEV and can facilitate development of vaccines and candidate antibody therapeutics.
Assuntos
Aerossóis/administração & dosagem , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Vírus da Encefalite Equina do Leste/imunologia , Encefalomielite Equina/imunologia , Encefalomielite Equina/prevenção & controle , Adulto , Animais , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Neutralizantes/imunologia , Antígenos Virais/imunologia , Microscopia Crioeletrônica , Modelos Animais de Doenças , Vírus da Encefalite Equina do Leste/ultraestrutura , Encefalomielite Equina/virologia , Epitopos/química , Feminino , Glicoproteínas/imunologia , Humanos , Camundongos , Modelos Moleculares , Mutagênese/genética , Testes de Neutralização , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes/imunologia , Sindbis virus/imunologia , Vírion/imunologia , Vírion/ultraestrutura , Internalização do VírusRESUMO
Hendra (HeV) and Nipah (NiV) viruses are emerging zoonotic pathogens in the Henipavirus genus causing outbreaks of disease with very high case fatality rates. Here, we report the first naturally occurring human monoclonal antibodies (mAbs) against HeV receptor binding protein (RBP). All isolated mAbs neutralized HeV, and some also neutralized NiV. Epitope binning experiments identified five major antigenic sites on HeV-RBP. Animal studies demonstrated that the most potent cross-reactive neutralizing mAbs, HENV-26 and HENV-32, protected ferrets in lethal models of infection with NiV Bangladesh 3 days after exposure. We solved the crystal structures of mAb HENV-26 in complex with both HeV-RBP and NiV-RBP and of mAb HENV-32 in complex with HeV-RBP. The studies reveal diverse sites of vulnerability on RBP recognized by potent human mAbs that inhibit virus by multiple mechanisms. These studies identify promising prophylactic antibodies and define protective epitopes that can be used in rational vaccine design.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vírus Hendra/imunologia , Henipavirus/imunologia , Testes de Neutralização , Vírus Nipah/imunologia , Receptores Virais/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/isolamento & purificação , Antígenos Virais/imunologia , Sítios de Ligação , Ligação Competitiva , Encéfalo/patologia , Quirópteros/virologia , Reações Cruzadas/imunologia , Cristalografia por Raios X , Efrina-B2/metabolismo , Feminino , Furões/virologia , Humanos , Interferometria , Fígado/patologia , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Receptores Virais/química , Receptores Virais/metabolismoRESUMO
Brain metastasis (br-met) develops in an immunologically unique br-met niche. Central nervous system-native myeloid cells (CNS-myeloids) and bone-marrow-derived myeloid cells (BMDMs) cooperatively regulate brain immunity. The phenotypic heterogeneity and specific roles of these myeloid subsets in shaping the br-met niche to regulate br-met outgrowth have not been fully revealed. Applying multimodal single-cell analyses, we elucidated a heterogeneous but spatially defined CNS-myeloid response during br-met outgrowth. We found Ccr2+ BMDMs minimally influenced br-met while CNS-myeloid promoted br-met outgrowth. Additionally, br-met-associated CNS-myeloid exhibited downregulation of Cx3cr1. Cx3cr1 knockout in CNS-myeloid increased br-met incidence, leading to an enriched interferon response signature and Cxcl10 upregulation. Significantly, neutralization of Cxcl10 reduced br-met, while rCxcl10 increased br-met and recruited VISTAHi PD-L1+ CNS-myeloid to br-met lesions. Inhibiting VISTA- and PD-L1-signaling relieved immune suppression and reduced br-met burden. Our results demonstrate that loss of Cx3cr1 in CNS-myeloid triggers a Cxcl10-mediated vicious cycle, cultivating a br-met-promoting, immune-suppressive niche.
Assuntos
Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/secundário , Quimiocina CXCL10/metabolismo , Terapia de Imunossupressão , Células Mieloides/metabolismo , Animais , Células da Medula Óssea/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Receptor 1 de Quimiocina CX3C/metabolismo , Sistema Nervoso Central/patologia , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Interferons/metabolismo , Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Testes de Neutralização , Fenótipo , Linfócitos T/imunologia , Transcriptoma/genéticaRESUMO
The global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic requires effective therapies against coronavirus disease 2019 (COVID-19), and neutralizing antibodies are a promising therapy. A noncompeting pair of human neutralizing antibodies (B38 and H4) blocking SARS-CoV-2 binding to its receptor, ACE2, have been described previously. Here, we develop bsAb15, a bispecific monoclonal antibody (bsAb) based on B38 and H4. bsAb15 has greater neutralizing efficiency than these parental antibodies, results in less selective pressure and retains neutralizing ability to most SARS-CoV-2 variants of concern (with more potent neutralizing activity against the Delta variant). We also selected for escape mutants of the two parental mAbs, a mAb cocktail and bsAb15, demonstrating that bsAb15 can efficiently neutralize all single-mAb escape mutants. Furthermore, prophylactic and therapeutic application of bsAb15 reduced the viral titer in infected nonhuman primates and human ACE2 transgenic mice. Therefore, this bsAb is a feasible and effective strategy to treat and prevent severe COVID-19.
Assuntos
Anticorpos Biespecíficos/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Biespecíficos/química , Anticorpos Biespecíficos/genética , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , COVID-19/imunologia , COVID-19/patologia , COVID-19/prevenção & controle , COVID-19/virologia , Clonagem Molecular , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Epitopos , Humanos , Macaca mulatta , Camundongos , Testes de Neutralização , Engenharia de Proteínas/métodos , Relação Estrutura-AtividadeRESUMO
Prevention of viral escape and increased coverage against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern require therapeutic monoclonal antibodies (mAbs) targeting multiple sites of vulnerability on the coronavirus spike glycoprotein. Here we identify several potent neutralizing antibodies directed against either the N-terminal domain (NTD) or the receptor-binding domain (RBD) of the spike protein. Administered in combinations, these mAbs provided low-dose protection against SARS-CoV-2 infection in the K18-human angiotensin-converting enzyme 2 mouse model, using both neutralization and Fc effector antibody functions. The RBD mAb WRAIR-2125, which targets residue F486 through a unique heavy-chain and light-chain pairing, demonstrated potent neutralizing activity against all major SARS-CoV-2 variants of concern. In combination with NTD and other RBD mAbs, WRAIR-2125 also prevented viral escape. These data demonstrate that NTD/RBD mAb combinations confer potent protection, likely leveraging complementary mechanisms of viral inactivation and clearance.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/metabolismo , Sítios de Ligação/genética , COVID-19/metabolismo , COVID-19/prevenção & controle , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Mapeamento de Epitopos , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Humanos , Camundongos Transgênicos , Testes de Neutralização , Ligação Proteica , Conformação Proteica , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Homologia de Sequência de Aminoácidos , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Análise de SobrevidaRESUMO
Neutralizing antibodies can block infection, clear pathogens, and are essential to provide long-term immunity. Since the onset of the pandemic, SARS-CoV-2 neutralizing antibodies have been comprehensively investigated and critical information on their development, function, and potential use to prevent and treat COVID-19 have been revealed. With the emergence of SARS-CoV-2 immune escape variants, humoral immunity is being challenged, and a detailed understanding of neutralizing antibodies is essential to guide vaccine design strategies as well as antibody-mediated therapies. In this review, we summarize some of the key findings on SARS-CoV-2 neutralizing antibodies, with a focus on their clinical application.