Detection of #MERS-CoV #antigen on #formalin-fixed paraffin-embedded #nasal #tissue of #alpacas by immunohistochemistry using #human #mAbs directed against different epitopes of the spike protein (Vet Immunol Immunopathol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Vet Immunol Immunopathol. 2019 Sep 9;218:109939. doi: 10.1016/j.vetimm.2019.109939. [Epub ahead of print]

Detection of MERS-CoV antigen on formalin-fixed paraffin-embedded nasal tissue of alpacas by immunohistochemistry using human monoclonal antibodies directed against different epitopes of the spike protein.

Haverkamp AK1, Bosch BJ2, Spitzbarth I3, Lehmbecker A3, Te N4, Bensaid A4, Segalés J5, Baumgärtner W6.

Author information: 1 Department of Pathology, University of Veterinary Medicine Hannover Foundation, 30559 Hannover, Germany. 2 Virology Division, Department of Infectious Diseases & Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands. 3 Department of Pathology, University of Veterinary Medicine Hannover Foundation, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany. 4 IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. 5 Departament de Sanitat i Anatomia Animals, Facultat de Veterinària, UAB, 08193 Bellaterra, Barcelona, Spain; UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. 6 Department of Pathology, University of Veterinary Medicine Hannover Foundation, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany. Electronic address: Wolfgang.Baumgaertner@tiho-hannover.de.

 

Abstract

Middle East respiratory syndrome (MERS) represents an important respiratory disease accompanied by lethal outcome in one third of human patients. In recent years, several investigators developed protective antibodies which could be used as prophylaxis in prospective human epidemics. In the current study, eight human monoclonal antibodies (mAbs) with neutralizing and non-neutralizing capabilities, directed against different epitopes of the MERS-coronavirus (MERS-CoV) spike (MERS-S) protein, were investigated with regard to their ability to immunohistochemically detect respective epitopes on formalin-fixed paraffin-embedded (FFPE) nasal tissue sections of MERS-CoV experimentally infected alpacas. The most intense immunoreaction was detected using a neutralizing antibody directed against the receptor binding domain S1B of the MERS-S protein, which produced an immunosignal in the cytoplasm of ciliated respiratory epithelium and along the apical membranous region. A similar staining was obtained by two other mAbs which recognize the sialic acid-binding domain and the ectodomain of the membrane fusion subunit S2, respectively. Five mAbs lacked immunoreactivity for MERS-CoV antigen on FFPE tissue, even though they belong, at least in part, to the same epitope group. In summary, three tested human mAbs demonstrated capacity for detection of MERS-CoV antigen on FFPE samples and may be implemented in double or triple immunohistochemical methods.

Copyright © 2019 Elsevier B.V. All rights reserved.

KEYWORDS: Immunohistochemistry; Middle East respiratory syndrome coronavirus; Monoclonal human antibodies; Spike protein

PMID: 31526954 DOI: 10.1016/j.vetimm.2019.109939

Keywords: MERS-CoV; Monoclonal antibodies; Diagnostic tests.

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Differential requirements for FcγR engagement by protective #antibodies against #Ebola virus (Proc Natl Acad Sci USA., abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Differential requirements for FcγR engagement by protective antibodies against Ebola virus

Stylianos Bournazos, David J. DiLillo, Arthur J. Goff, Pamela J. Glass, and Jeffrey V. Ravetch

PNAS first published September 4, 2019 / DOI: https://doi.org/10.1073/pnas.1911842116

Contributed by Jeffrey V. Ravetch, August 9, 2019 (sent for review July 11, 2019; reviewed by Robert M. Anthony, Diane Mathis, and Rino Rappuoli)

 

Significance

In recent years, systematic research efforts have led to the preclinical development of antibody-based therapeutics that confer potent antiviral activity against Ebola virus (EBOV). Immunoglobulin G (IgG) antibodies against virus pathogens depend on their interaction with specialized leukocyte receptors (Fcγ receptors [FcγRs]) to confer antiviral functions. FcγR engagement by IgG antibodies induces leukocyte activation and mediates pleiotropic effector functions to control virus infection. Here, we examined the contribution of FcγR engagement to the antibody-mediated protection against EBOV infection in unique animal models of EBOV infection. Our findings suggest that anti-EBOV antibodies exhibit differential requirements for FcγR engagement to confer protection from EBOV infection, guiding the design of optimized antibody-based therapeutics with maximal protective efficacy.

 

Abstract

Ebola virus (EBOV) continues to pose significant threats to global public health, requiring ongoing development of multiple strategies for disease control. To date, numerous monoclonal antibodies (mAbs) that target the EBOV glycoprotein (GP) have demonstrated potent protective activity in animal disease models and are thus promising candidates for the control of EBOV. However, recent work in a variety of virus diseases has highlighted the importance of coupling Fab neutralization with Fc effector activity for effective antibody-mediated protection. To determine the contribution of Fc effector activity to the protective function of mAbs to EBOV GP, we selected anti-GP mAbs targeting representative, protective epitopes and characterized their Fc receptor (FcγR) dependence in vivo in FcγR humanized mouse challenge models of EBOV disease. In contrast to previous studies, we find that anti-GP mAbs exhibited differential requirements for FcγR engagement in mediating their protective activity independent of their distance from the viral membrane. Anti-GP mAbs targeting membrane proximal epitopes or the GP mucin domain do not rely on Fc–FcγR interactions to confer activity, whereas antibodies against the GP chalice bowl and the fusion loop require FcγR engagement for optimal in vivo antiviral activity. This complexity of antibody-mediated protection from EBOV disease highlights the structural constraints of FcγR binding for specific viral epitopes and has important implications for the development of mAb-based immunotherapeutics with optimal potency and efficacy.

antibodies – effector function – immunoglobulin – Fc receptors – immunotherapy

Keywords: Ebola; Monoclonal antibodies; Immunotherapy; Immunoglobulins.

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#Antibody #therapy for #Lassa fever (Curr Opin Virol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Curr Opin Virol. 2019 Aug 8;37:97-104. doi: 10.1016/j.coviro.2019.07.003. [Epub ahead of print]

Antibody therapy for Lassa fever.

Cross RW1, Hastie KM2, Mire CE1, Robinson JE3, Geisbert TW1, Branco LM4, Ollmann Saphire E2, Garry RF5.

Author information: 1 Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA. 2 La Jolla Institute for Immunology, La Jolla, CA 92037, USA. 3 Department of Pediatrics, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA. 4 Zalgen Labs, LLC, Germantown, MD 20876, USA. 5 Zalgen Labs, LLC, Germantown, MD 20876, USA; Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA. Electronic address: rfgarry@tulane.edu.

 

Abstract

Serum from convalescent Lassa fever patients was previously shown to be ineffective as a source of protective antibodies in some early studies. Subsequently, monoclonal antibodies (MAbs) to the Lassa virus (LASV) glycoprotein produced by memory B cells of West African patients who survived Lassa fever were identified. Development of MAbs as potential Lassa immunotherapeutics was facilitated by structural studies and mutational analyses that identified protective epitopes on the prefusion form of the LASV glycoprotein. Human mAbs were screened for reactivity to different neutralizing epitopes, potency, and broad reactivity against multiple lineages of LASV. MAbs were downselected in a guinea pig model of Lassa fever. A cocktail of three human MAbs designated Arevirumab-3 rescued 100% of Cynomolgus macaques at advanced stages of disease more than a week post-infection. Antibody therapeutics may be further developed in clinical trials in endemic areas potentially offering a key treatment option for Lassa fever.

Copyright © 2019 Elsevier B.V. All rights reserved.

PMID: 31401518 DOI: 10.1016/j.coviro.2019.07.003

Keywords: Serotherapy; Monoclonal antibodies; Lassa fever.

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#Survival during #influenza-associated #bacterial #superinfection improves following viral- and bacterial-specific #monoclonal #antibody treatment (JCI Insight., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

JCI Insight. 2019 Jul 25;4(14). pii: 125554. doi: 10.1172/jci.insight.125554. eCollection 2019 Jul 25.

Survival during influenza-associated bacterial superinfection improves following viral- and bacterial-specific monoclonal antibody treatment.

Robinson KM1, Ramanan K1, Tobin JM1, Nickolich KL1, Pilewski MJ1, Kallewaard NL2, Sellman BR2, Cohen TS2, Alcorn JF3.

Author information: 1 Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. 2 Department of Microbial Sciences, MedImmune, Gaithersburg, Maryland, USA. 3 Division of Pulmonary Medicine, Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.

 

Abstract

Postinfluenza bacterial superinfections cause increased morbidity and mortality compared with singular infection with influenza during both pandemics and seasonal epidemics. Vaccines and current treatments provide limited benefit, a rationale to conduct studies utilizing alternative therapies. FY1 and an optimized version, MEDI8852, anti-influenza HA mAbs, have been shown to neutralize influenza virus during singular influenza infection. MEDI4893*, an anti-Staphylococcus aureus α-toxin mAb, has been shown to improve survival when administered prophylactically prior to S. aureus pneumonia. Our objective was to determine if mAbs can improve survival during postinfluenza bacterial pneumonia. We administered FY1 in a murine model of postinfluenza methicillin-resistant S. aureus (MRSA) pneumonia and observed improved survival rates when given early during the course of influenza infection. Our findings indicate decreased lung injury and increased uptake and binding of bacteria by macrophages in the mice that received FY1 earlier in the course of influenza infection, corresponding to decreased bacterial burden. We also observed improved survival when mice were treated with a combination of FY1 and MEDI4893* late during the course of postinfluenza MRSA pneumonia. In conclusion, both FY1 and MEDI4893* prolong survival when used in a murine model of postinfluenza MRSA pneumonia, suggesting pathogen-specific mAbs as a possible therapeutic in the context of bacterial superinfection.

KEYWORDS: Bacterial infections; Immunology; Infectious disease; Influenza

PMID: 31341107 DOI: 10.1172/jci.insight.125554

Keywords: Influenza A; MRSA; Staphylococcus aureus; Monoclonal antibodies; Anima models.

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Rapid #isolation of a potent #human #antibody against #H7N9 #influenza virus from an infected #patient (Antiviral Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Antiviral Res. 2019 Jul 20:104564. doi: 10.1016/j.antiviral.2019.104564. [Epub ahead of print]

Rapid isolation of a potent human antibody against H7N9 influenza virus from an infected patient.

Li J1, Yang Y2, Wang M3, Ren X4, Yang Z5, Liu L6, Zhang G6, Chen Q1, Yang W7, Chen YH8, Wan X9.

Author information: 1 Shenzhen Laboratory of Human Antibody Engineering, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Boulevard, University City of Shenzhen, Xili Nanshan, Shenzhen, 518055, China; School of Life Sciences, University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District, Beijing, 100049, PR China. 2 Shenzhen Key Laboratory of Pathogen and Immunity, Guangdong Key Laboratory for Diagnosis and Treatment of Emerging Infectious Diseases, State Key Discipline of Infectious Disease, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen Third People’s Hospital, Shenzhen, 518112, China. 3 CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing, 100101, China. 4 Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, No 8 Longyuan Road, Nanshan District, Shenzhen, 518055, China. 5 (f)Shenzhen Center for Chronic Disease Control, No.2021 Buxin Road, Luohu District, Shenzhen, 51822, China. 6 Shenzhen Laboratory of Human Antibody Engineering, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Boulevard, University City of Shenzhen, Xili Nanshan, Shenzhen, 518055, China. 7 Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China. 8 Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104, USA. 9 Shenzhen Laboratory of Human Antibody Engineering, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Boulevard, University City of Shenzhen, Xili Nanshan, Shenzhen, 518055, China. Electronic address: xc.wan@siat.ac.cn.

 

Abstract

Influenza virus A H7N9 remains a serious threat to public health due to the lack of effective vaccines and drugs. In this study, a neutralizing human antibody named 3L11 was rapidly isolated from the switched memory B cells of a patient infected with H7N9. The antibody 3L11 was encoded by the heavy-chain VH1-8 gene and the light-chain VL2-13 gene that had undergone somatic mutations, and conferred high affinity binding to H7N9 hemagglutinins (HAs). It promoted killing of infected cells by antibody-dependent cell-mediated cytotoxicity (ADCC). Epitope mapping by mass spectroscopy (MS) indicated that 3L11 bound to the peptide 149-175 of HAs that contained the 150-loop of the receptor-binding site (RBS). Additionally, the 3L11 escape strains had G151R (Gly151→Arg151) and S152P (Ser152→Pro152) mutations within a conserved antigenic site A near the RBS that were not observed in field strains. Importantly, 3L11 fully protected mice against a lethal H7N9 virus challenge, in both pre- and postexposure administration regimens. Altogether, this work demonstrates the feasibility of rapid isolation of neutralizing H7N9 antibodies from infected patients and provides a potential prophylactic and therapeutic agent against H7N9 viruses.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: ADCC; Antigenic site A; H7N9; Human monoclonal antibody; Mass spectroscopy; Switched memory B cells

PMID: 31336147 DOI: 10.1016/j.antiviral.2019.104564

Keywords: Influenza A; Avian Influenza; Human; H7N9; Monoclonal antibodies.

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Neutralizing #antibodies against #Mayaro virus require Fc effector functions for protective activity (J Exp Med., abstract)

[Source: Journal of Experimental Medicine, full page: (LINK). Abstract, edited.]

Neutralizing antibodies against Mayaro virus require Fc effector functions for protective activity

James T. Earnest, Katherine Basore, Vicky Roy, Adam L. Bailey, David Wang, Galit Alter, Daved H. Fremont, Michael S. Diamond

DOI: 10.1084/jem.20190736 | Published July 23, 201

 

Abstract

Despite causing outbreaks of fever and arthritis in multiple countries, no countermeasures exist against Mayaro virus (MAYV), an emerging mosquito-transmitted alphavirus. We generated 18 neutralizing mAbs against MAYV, 11 of which had “elite” activity that inhibited infection with EC50values of <10 ng/ml. Antibodies with the greatest inhibitory capacity in cell culture mapped to epitopes near the fusion peptide of E1 and in domain B of the E2 glycoproteins. Unexpectedly, many of the elite neutralizing mAbs failed to prevent MAYV infection and disease in vivo. Instead, the most protective mAbs bound viral antigen on the cell surface with high avidity and promoted specific Fc effector functions, including phagocytosis by neutrophils and monocytes. In subclass switching studies, murine IgG2a and humanized IgG1 mAb variants controlled infection better than murine IgG1 and humanized IgG1-N297Q variants. An optimally protective antibody response to MAYV and possibly other alphaviruses may require tandem virus neutralization by the Fab moiety and effector functions of the Fc region.

Submitted: 24 April 2019 – Revision received 11 June 2019 – Accepted: 20 June 2019

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).

Keywords: Alphavirus; Mayaro virus; Monoclonal antibodies.

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A cross-reactive #human #monoclonal #antibody targets the conserved #H7 #antigenic site a from fifth wave #H7N9-infected humans (Antiviral Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Antiviral Res. 2019 Jul 9:104556. doi: 10.1016/j.antiviral.2019.104556. [Epub ahead of print]

A cross-reactive human monoclonal antibody targets the conserved H7 antigenic site a from fifth wave H7N9-infected humans.

Li M1, Chen L1, Wang Q1, Hao M2, Zhang X1, Liu L3, Yu X3, Yang C1, Xu J4, Chen J5, Gong R6.

Author information: 1 CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China. 2 CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, 430071, China; National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China. 3 Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China. 4 Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China. Electronic address: 609564945@qq.com. 5 CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, 430071, China; National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China. Electronic address: chenjj@wh.iov.cn. 6 CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, 430071, China. Electronic address: gongr@wh.iov.cn.

 

Abstract

Subtype H7 avian influenza viruses have been found to be associated with human infection and represent a risk for global public health. In 2013, the emergence of H7N9 virus in human beings and persistent human infection in China raised the most serious pandemic threat. Here we identified a human monoclonal antibody, P52E03, targeting the hemagglutinin (HA) of subtype H7 influenza viruses (H7 antigen), from a convalescent patient infected with H7N9 in 2017. P52E03 showed in vitro hemagglutination inhibiting (HI) and neutralizing activity against subtype H7 viruses belonging to both North American and Eurasian lineages. Moreover, it could prophylactically protect mice against weight loss and death caused by challenge with lethal H7N9 viruses in vivo and, therefore, is a candidate for development of antiviral agent against H7N9 infection. By generating escape mutant variants, we found that a single G151E substitution in the viral H7 antigenic site A could abort the neutralizing activity. Computational structural prediction of the P52E03/H7 complex revealed that residues including G151 in and around the conserved antigenic A region are important for antigen recognition by the H7 cross-reactive antibody. Finally, we found that the P52E03 germline precursor (gHgL) antibody recognizes HA with measurable affinity, suggesting that its epitope is vulnerable to the human immune system and might elicit neutralizing antibodies (nAbs) in vivo after vaccination.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: Antibody; Epitope; H7N9; Hemagglutination inhibiting; Influenza virus; Neutralizing

PMID: 31299269 DOI: 10.1016/j.antiviral.2019.104556

Keywords: Avian Influenza; H7N9; Monoclonal antibodies.

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