Exceptionally potent neutralization of Middle East respiratory syndrome coronavirus by human monoclonal antibodies.
The recently discovered Middle East respiratory syndrome coronavirus (MERS-CoV) continues to infect humans, with high mortality. Specific, highly effective therapeutics and vaccines against the MERS-CoV are urgently needed to save human lives and address the pandemic concerns. We identified three human monoclonal antibodies (MAbs), m336, m337, and m338, targeting the receptor (CD26/DPP4) binding domain (RBD) of the MERS-CoV spike glycoprotein from a very large naïve-antibody library (containing ∼10(11) antibodies). They bound with high affinity: equilibrium dissociation constants for the three MAbs were equal to 4.2, 9.3, and 15 nM, respectively, as measured by Biacore for Fabs binding to RBD. The avidity for IgG1 m336, m337, and m338 was even higher: 99, 820, and 560 pM, respectively. The antibodies bound to overlapping epitopes that overlap the receptor binding site on the RBD as suggested by competition experiments and further supported by site-directed mutagenesis of the RBD and a docking model of the m336-RBD complex. The highest-affinity MAb, m336, neutralized both pseudotyped and live MERS-CoV with exceptional potency, 50% neutralization at 0.005 and 0.07 μg/ml, respectively, likely by competing with DPP4 for binding to the S glycoprotein. The exceptionally high neutralization activity of these antibodies and especially m336 suggests that they have great potential for prophylaxis and therapy of MERS-CoV infection in humans and as a tool for development of vaccine immunogens. The rapid identification (within several weeks) of potent MAbs suggests a possibility to use the new large antibody library and related methodology for a quick response to the public threat resulting from emerging coronaviruses. Importance: A novel human coronavirus, the Middle East respiratory syndrome coronavirus (MERS-CoV), was found to infect humans with a high mortality rate in 2012, just 1 decade after the appearance of the first highly pathogenic coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV). There are no effective therapeutics available. It is highly desirable to find an approach for rapidly developing potent therapeutics against MERS-CoV, which not only can be implemented for MERS treatment but also can help to develop a platform strategy to combat future emerging coronaviruses. We report here the identification of human monoclonal antibodies (MAbs) from a large nonimmune antibody library that target MERS-CoV. One of the antibodies, m336, neutralized the virus with exceptional potency. It therefore may have great potential as a candidate therapeutic and as a reagent to facilitate the development of vaccines against MERS-CoV.
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA yingt@mail.nih.gov dimiter.dimitrov@nih.gov.
Tianlei
T
Ying
Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA.
Lanying
L
Du
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA.
Tina W
TW
Ju
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA.
Ponraj
P
Prabakaran
Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong.
Candy C Y
CC
Lau
Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China.
Lu
L
Lu
Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China.
Qi
Q
Liu
Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA.
Lili
L
Wang
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA.
Yang
Y
Feng
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA.
Yanping
Y
Wang
Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA.
Bo-Jian
BJ
Zheng
Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA.
Kwok-Yung
KY
Yuen
Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China.
Shibo
S
Jiang
Protein Interactions Group, Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA yingt@mail.nih.gov dimiter.dimitrov@nih.gov.
Dimiter S
DS
Dimitrov
D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification; D057134:Antibodies, Neutralizing / Q000276:immunology* / Q000302:isolation & purification; D000914:Antibodies, Viral / Q000276:immunology* / Q000302:isolation & purification; D000915:Antibody Affinity; D001665:Binding Sites; D017934:Coronavirus / Q000276:immunology*; D018604:Epitope Mapping; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000302:isolation & purification; D007700:Kinetics; D062105:Molecular Docking Simulation; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests; D019151:Peptide Library; D011485:Protein Binding
D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007074:Immunoglobulin G; D019151:Peptide Library