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.



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.



#ADE of #influenza #disease promoted by increase in #hemagglutinin stem flexibility and virus #fusion kinetics (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.]

Antibody-dependent enhancement of influenza disease promoted by increase in hemagglutinin stem flexibility and virus fusion kinetics

Katie L. Winarski, Juanjie Tang, Laura Klenow, Jeehyun Lee, Elizabeth M. Coyle, Jody Manischewitz, Hannah L. Turner, Kazuyo Takeda, Andrew B. Ward, Hana Golding, and Surender Khurana

PNAS first published July 11, 2019 / DOI: https://doi.org/10.1073/pnas.1821317116

Edited by Robert G. Webster, St. Jude Children’s Research Hospital, Memphis, TN, and approved June 19, 2019 (received for review December 14, 2018)



Next-generation influenza vaccines and broadly neutralizing antibodies (bNAbs) are in clinical development. Some of these do not block virus–receptor interactions and thus are predicted to provide protection via alternative mechanisms at the postentry stage or use Fc-dependent mechanisms. Nonneutralizing antibodies have the potential to mediate enhancement of respiratory disease (ERD). Our study describes ADE with two different functional MAbs that destabilized HA stem domain, increased influenza virus fusion kinetics, and led to enhanced lung pathology and ERD in a dose-dependent manner in a mice model. This study underlines careful preclinical evaluation of next-generation influenza vaccines or antibody-based therapeutics that do not block influenza virus receptor binding.



Several next-generation (universal) influenza vaccines and broadly neutralizing antibodies (bNAbs) are in clinical development. Some of these mediate inhibitions of virus replication at the postentry stage or use Fc-dependent mechanisms. Nonneutralizing antibodies have the potential to mediate enhancement of viral infection or disease. In the current study, two monoclonal antibodies (MAbs) 72/8 and 69/1, enhanced respiratory disease (ERD) in mice following H3N2 virus challenge by demonstrating increased lung pathology and changes in lung cytokine/chemokine levels. MAb 78/2 caused changes in the lung viral loads in a dose-dependent manner. Both MAbs increased HA sensitivity to trypsin cleavage at a higher pH range, suggesting MAb-induced conformational changes. pHrodo-labeled virus particles’ entry and residence time in the endocytic compartment were tracked during infection of Madin-Darby canine kidney (MDCK) cells. Both MAbs reduced H3N2 virus residence time in the endocytic pathway, suggesting faster virus fusion kinetics. Structurally, 78/2 and 69/1 Fabs bound the globular head or base of the head domain of influenza hemagglutinin (HA), respectively, and induced destabilization of the HA stem domain. Together, this study describes Mab-induced destabilization of the influenza HA stem domain, faster kinetics of influenza virus fusion, and ERD in vivo. The in vivo animal model and in vitro assays described could augment preclinical safety evaluation of antibodies and next-generation influenza vaccines that generate antibodies which do not block influenza virus–receptor interaction.

universal – stem – influenza – antibody-dependent enhancement (ADE) – vaccine



1 K.L.W., J.T., and L.K. contributed equally to this work.

2 To whom correspondence may be addressed. Email: Surender.Khurana@fda.hhs.gov.

Author contributions: S.K. designed research; K.L.W., J.T., L.K., J.L., E.M.C., J.M., H.L.T., K.T., A.B.W., and S.K. performed research; K.L.W., J.T., L.K., H.L.T., K.T., A.B.W., and S.K. analyzed data; and A.B.W., H.G., and S.K. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1821317116/-/DCSupplemental.

Published under the PNAS license.

Keywords: Influenza A; Monoclonal antibodies; Vaccines; Antibody Dependent Enhancement.


A potent neutralizing site III-specific #human #antibody neutralizes human #metapneumovirus in vivo (J Virol., abstract)

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

A potent neutralizing site III-specific human antibody neutralizes human metapneumovirus in vivo

Yael Bar-Peled, Darren Diaz, Alma Pena-Briseno, Jackelyn Murray, Jiachen Huang, Ralph A. Tripp, Jarrod J. Mousa

DOI: 10.1128/JVI.00342-19



Human metapneumovirus (hMPV) is a leading cause of viral lower respiratory tract infection in children. The sole target of neutralizing antibodies targeting hMPV is the fusion (F) protein, a class I viral fusion protein mediating virus-cell membrane fusion. There have been several monoclonal antibodies (mAbs) isolated that neutralize hMPV, however, determining the antigenic sites on the hMPV F protein mediating such neutralizing antibody generation would assist efforts for effective vaccine design. In this report, the isolation and characterization of four new human mAbs is described, termed MPV196, MPV201, MPV314, and MPV364. Among the four mAbs, MPV364 was found to be the most potent neutralizing mAb in vitro. Binding studies to monomeric and trimeric hMPV F revealed that MPV364 had the weakest binding affinity to monomeric hMPV F as compared to the other three mAbs, yet binding experiments to trimeric hMPV F showed limited difference in binding affinity, suggesting MPV364 targets an antigenic site incorporating two protomers. Epitope binning studies showed that MPV364 targets antigenic site III on the hMPV F protein and competes for binding with previously discovered mAbs MPE8 and 25P13, which both cross-react with the respiratory syncytial virus (RSV) F protein. However, MPV364 does not cross-react with the RSV F protein, and the competition profile suggests it binds to the hMPV F protein in a binding pose slightly shifted from mAbs MPE8 and 25P13. MPV364 was further assessed in vivo and was shown to substantially reduce viral replication in the lungs of BALB/c mice. Overall, these data reveal a new binding region near antigenic site III of the hMPV F protein that elicits potent neutralizing hMPV F-specific mAbs, and provide a new panel of neutralizing mAbs that are candidates for therapeutic development.



Recent progress in understanding the human immune response to respiratory syncytial virus has paved the way for new vaccine antigens and therapeutics to prevent and treat disease. Progress toward understanding the immune response to human metapneumovirus (hMPV) has lagged behind, although hMPV is a leading cause of lower respiratory tract infection in children. In this report, we advanced the field by isolating a panel of human mAbs to the hMPV F protein. One potent neutralizing mAb, MPV364, targets antigenic site III on the hMPV F protein and incorporates two protomers into its epitope, yet is unique from previously discovered site III-mAbs as it does not cross-react with the RSV F protein. We further examined MPV364 in vivo, and found it limits viral replication in BALB/c mice. Altogether, these data provide new mAb candidates for therapeutic development, and provide insights into hMPV vaccine development.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Metapneumovirus; Monoclonal antibodies.


Characterisation of #infectious #Ebola virus from the ongoing #outbreak to guide #response activities in the #DRC: a #phylogenetic and in vitro analysis (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Characterisation of infectious Ebola virus from the ongoing outbreak to guide response activities in the Democratic Republic of the Congo: a phylogenetic and in vitro analysis

Laura K McMullan, PhD, Mike Flint, PhD, Ayan Chakrabarti, MS, Lisa Guerrero, MPH, Michael K Lo, PhD, Danielle Porter, PhD, Stuart T Nichol, PhD, Christina F Spiropoulou, PhD, César Albariño, PhD

Published: July 09, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30291-9




The ongoing Ebola virus outbreak in the Ituri and North Kivu Provinces of the Democratic Republic of the Congo, which began in July, 2018, is the second largest ever recorded. Despite civil unrest, outbreak control measures and the administration of experimental therapies and a vaccine have been initiated. The aim of this study was to test the efficacy of candidate therapies and diagnostic tests with the outbreak strain Ituri Ebola virus. Lacking a virus isolate from this outbreak, a recombinant Ituri Ebola virus was compared with a similarly engineered Makona virus from the 2013–16 outbreak.


Using Ebola virus sequences provided by organisations in DR Congo and a reverse genetics system, we generated an authentic Ebola virus from the ongoing outbreak in Ituri and North Kivu provinces. To relate this virus to other Ebola viruses in DR Congo, we did a phylogenetic analysis of representative complete Ebola virus genome sequences from previous outbreaks. We evaluated experimental therapies being tested in clinical trials in DR Congo, including remdesivir and ZMapp monoclonal antibodies, for their ability to inhibit the growth of infectious Ituri Ebola virus in cell culture. We also tested diagnostic assays for detection of the Ituri Ebola virus sequence.


The phylogenetic analysis of whole-genome sequences from each Ebola virus outbreak suggests there are at least two Ebola virus strains in DR Congo, which have independently crossed into the human population. The Ituri Ebola strain initially grew slower than the Makona strain, yet reached similar mean yields of 3 × 10 7 50% tissue culture infectious dose by 72 h infection in Huh-7 cells. Ituri Ebola virus was similar to Makona in its susceptibility to inhibition by remdesivir and to neutralisation by monoclonal antibodies from ZMapp and other monoclonal antibodies. Remdesivir inhibited Ituri Ebola virus at a 50% effective concentration (EC 50) of 12nM (with a selectivity index of 303) and Makona Ebola virus at 13nM (with a selectivity index of 279). The Zmapp monoclonal antibodies 2G4 and 4G7 neutralised Ituri Ebola virus with a mean EC 50 of 0·24 μg/mL and 0·48 μg/mL, and Makona Ebola virus with a mean EC 50 of 0·45 μg/mL and 0·2 μg/mL. The Xpert Ebola and US Centers for Disease Control and Prevention real-time RT-qPCR diagnostic assays detected Ituri and Makona Ebola virus sequences with similar sensitivities and efficiencies, despite primer site binding mismatches in the Ituri Ebola virus.


Our findings provide a rationale for the continued testing of investigational therapies, confirm the effectiveness of the diagnostic assays used in the region, and establish a paradigm for the use of reverse genetics to inform response activities in an outbreak.


US Centers for Disease Control and Prevention.

Keywords: Ebola; Ebola-Makona; Ebola-Ituri; Antivirals; Monoclonal Antibodies; Zmapp; Remdesivir; DRC.


Development of a Specific #CHIKV-E2 #Monoclonal #Antibody for #Chikungunya #Diagnosis (Virol Sin., abstract)

[Source: Virologica Sinica, full page: (LINK). Abstract, edited.]

Development of a Specific CHIKV-E2 Monoclonal Antibody for Chikungunya Diagnosis

Authors: Jaemoo Kim, Jihyun Yang, Young Bong Kim, Hee-Jung Lee, Sehyun Kim, Haryoung Poo

Research Article / First Online: 18 June 2019



Chikungunya fever is a vector-borne viral disease transmitted to humans by chikungunya virus (CHIKV)-infected mosquitoes. There have been many outbreaks of CHIKV infection worldwide, and the virus poses ongoing risks to global health. To prevent and control CHIKV infection, it is important to improve the current CHIKV diagnostic approaches to allow for the detection of low CHIKV concentrations and to correctly distinguish CHIKV infections from those due to other mosquito-transmitted viruses, including dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV). Here, we produced monoclonal antibodies (mAbs) against the CHIKV envelope 2 protein (CHIKV-E2) and compared their sensitivity and specificity with commercially available mAbs using enzyme-linked immunosorbent assays (ELISA). Two anti-CHIKV-E2 mAbs, 19-1 and 21-1, showed higher binding affinities to CHIKV-E2 protein than the commercial mAbs did. In particular, the 19-1 mAb had the strongest binding affinity to inactivated CHIKV. Moreover, the 19-1 mAb had very little cross-reactivity with other mosquito-borne viruses, such as ZIKV, JEV, and DENV. These results suggest that the newly produced anti-CHIKV-E2 mAb, 19-1, could be used for CHIKV diagnostic approaches.

Keywords: Chikungunya virus – (CHIKV) Envelope 2 – Monoclonal antibody – Diagnosis – Sensitivity – Specificity




This work was supported by Grants from the R&D Convergence Program of National Research Council of Science & Technology (No. CAP-16-02-KIST) and the National Research Foundation of Korea (No. NRF-2016M3A9B6918584).

Author Contributions

HP designed the experiments; JK performed the experiments; SK, HL, and YK contributed to analyze cross-reactivities of anti-CHIKV-E2 antibodies to arboviruses; JK and JY analyzed the experiments and drafted the manuscript; HP supervised the experiments, analyzed results, and wrote the manuscript. All authors approved the final manuscript.


Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no competing interests.

Animal and Human Rights Statement

Animal experiments were approved by the Institutional Animal Care and Use Committee (IACUC) of the Korea Research Institute of Bioscience and Biotechnology (KRIBB) and performed according to the Guidelines for Animal Experiments of the KRIBB.

Keywords: Chikungunya fever; Monoclonal antibodies; Diagnostic tests.


Single #intranasal #immunization with chimpanzee #adenovirus-based #vaccine induces sustained and protective immunity against #MERS-CoV #infection (Emerg Microbes Infect., abstract)

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

Emerg Microbes Infect. 2019;8(1):760-772. doi: 10.1080/22221751.2019.1620083.

Single intranasal immunization with chimpanzee adenovirus-based vaccine induces sustained and protective immunity against MERS-CoV infection.

Jia W1, Channappanavar R2,3, Zhang C4,5, Li M1, Zhou H6, Zhang S6, Zhou P1, Xu J1, Shan S1, Shi X1, Wang X6, Zhao J7, Zhou D5, Perlman S2,7, Zhang L1.

Author information: 1a Comprehensive AIDS Research Center, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences , School of Medicine, Tsinghua University , Beijing , People’s Republic of China. 2b Department of Microbiology and Immunology , The University of Iowa , Iowa City , IA , USA. 3 c Department of Acute and Tertiary Care, and the Institute for the Study of Host-Pathogen Systems , University of Tennessee Health Science Center , Memphis , TN , USA. 4 d School of Medicine and Life Sciences, Nanjing University of Chinese Medicine , Nanjing , People’s Republic of China. 5 e Key Laboratory of Molecular Virology & Immunology, Vaccine Research Center , Institut Pasteur of Shanghai, Chinese Academy of Sciences , Shanghai , People’s Republic of China. 6 f The Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy , School of Life Sciences, Tsinghua University , Beijing , People’s Republic of China. 7 g State Key Laboratory of Respiratory Disease , Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University , Guangzhou , People’s Republic of China.



The recently identified Middle East Respiratory Syndrome Coronavirus (MERS-CoV) causes severe and fatal acute respiratory illness in humans. However, no approved prophylactic and therapeutic interventions are currently available. The MERS-CoV envelope spike protein serves as a crucial target for neutralizing antibodies and vaccine development, as it plays a critical role in mediating viral entry through interactions with the cellular receptor, dipeptidyl peptidase 4 (DPP4). Here, we constructed a recombinant rare serotype of the chimpanzee adenovirus 68 (AdC68) that expresses full-length MERS-CoV S protein (AdC68-S). Single intranasal immunization with AdC68-S induced robust and sustained neutralizing antibody and T cell responses in BALB/c mice. In a human DPP4 knock-in (hDPP4-KI) mouse model, it completely protected against lethal challenge with a mouse-adapted MERS-CoV (MERS-CoV-MA). Passive transfer of immune sera to naïve hDPP4-KI mice also provided survival advantages from lethal MERS-CoV-MA challenge. Analysis of sera absorption and isolated monoclonal antibodies from immunized mice demonstrated that the potent and broad neutralizing activity was largely attributed to antibodies targeting the receptor binding domain (RBD) of the S protein. These results show that AdC68-S can induce protective immune responses in mice and represent a promising candidate for further development against MERS-CoV infection in both dromedaries and humans.

KEYWORDS: MERS-CoV vaccine; chimpanzee adenoviral vector; intranasal immunization; monoclonal antibody; receptor binding domain (RBD)

PMID: 31130102 DOI: 10.1080/22221751.2019.1620083

Keywords: MERS-CoV; Vaccines; Serotherapy; Monoclonal antibodies; Animal models.


Penetration of a #mAb Combination (#ASN100) Targeting S. aureus #Cytotoxins in #Lung Epithelial Lining Fluid: … (Antimicrob Agents Chemother., abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Penetration of a Monoclonal Antibody Combination (ASN100) Targeting S. aureus Cytotoxins in Lung Epithelial Lining Fluid: A Randomized, Double-blind, Placebo-controlled, Single Ascending Dose Study in Healthy Volunteers.

Zoltan Magyarics, Fraser Leslie, Johann Bartko, Harald Rouha, Steven Luperchio, Christian Schörgenhofer, Michael Schwameis, Ulla Derhaschnig, Heimo Lagler, Leopold Stiebellehner,Christa Firbas, Susanne Weber, Ed Campanaro, Bernd Jilma, Eszter Nagy, Chris Stevens

DOI: 10.1128/AAC.00350-19



ASN100 is a novel antibody combination of two fully human IgG1 kappa monoclonal antibodies, ASN-1 and ASN-2 which neutralize six Staphylococcus aureus cytotoxins, alpha-hemolysin (Hla) and five bi-component leukocidins. We assessed the safety, tolerability, and serum and lung pharmacokinetics of ASN100 in a randomized, double-blind, placebo-controlled single dose escalation first-in-human study.

Fifty-two healthy volunteers were enrolled and randomized to receive either ASN-1, ASN-2, or a combination of both mAbs (ASN100), or corresponding placebo. Thirty-two subjects in the double-blind dose escalation portion of the study received ASN-1 or ASN-2 at a 200, 600, 1800, or 4000 mg dose, or placebo. Eight subjects received both mAbs simultaneously in a 1:1 ratio (ASN100) at 3600 or 8000 mg, or placebos. Twelve additional subjects received open-label ASN100 at 3600 or 8000 mg to assess the pharmacokinetics of ASN-1 and ASN-2 in epithelial lining fluid (ELF) by bronchoalveolar lavage fluid sampling. Subjects were followed for 98 days (double-blind cohorts) or 30 days (open-label cohorts) for safety assessment.

No dose-limiting toxicities were observed and all adverse events were mild and transient, with only two adverse events considered possibly related to the Investigational Product. ASN100 exhibited linear serum PK with a half-life of approximately three weeks and showed detectable penetration into the ELF. No treatment-emergent anti-drug antibody responses were detected. The toxin neutralizing potency of ASN100 in human serum was confirmed up to 58 days post-dosing.

The favorable safety profile, ELF penetration, and maintained functional activity in serum supported the further clinical development of ASN100.

Copyright © 2019 Magyarics et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.

Keywords: Antibiotics; Staphylococcus aureus; Monoclonal antibodies.