Molecular characterization of the monoclonal antibodies composing ZMAb: a protective cocktail against Ebola virus.
Ebola virus (EBOV) causes severe viral hemorrhagic fever in humans and non-human primates, with a case fatality rate of up to 88% in human outbreaks. Over the past 3 years, monoclonal antibody (mAb) cocktails have demonstrated high efficacy as treatments against EBOV infection. One such cocktail is ZMAb, which consists of three mouse antibodies, 1H3, 2G4, and 4G7. Here, we present the epitope binding properties of mAbs 1H3, 2G4, and 4G7. We showed that these antibodies have different variable region sequences, suggesting that the individual mAbs are not clonally related. All three antibodies were found to neutralize EBOV variant Mayinga. Additionally, 2G4 and 4G7 were shown to cross-inhibit each other in vitro and select for an escape mutation at the same position on the EBOV glycoprotein (GP), at amino acid 508. 1H3 selects an escape mutant at amino acid 273 on EBOV GP. Surface plasmon resonance studies showed that all three antibodies have dissociation constants on the order of 10(-7). In combination with previous studies evaluating the binding sites of other protective antibodies, our results suggest that antibodies targeting the GP1-GP2 interface and the glycan cap are often selected as efficacious antibodies for post-exposure interventions against EBOV.
Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada, R3E 0J9.
Jonathan
J
Audet
Special Pathogens Program, Canadian Science Center for Human and Animal Health, Public Health Agency of Canada, Winnipeg, Canada, R3E 3R2.
Gary
G
Wong
CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P.R. China.
Han
H
Wang
CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P.R. China.
Guangwen
G
Lu
CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P.R. China.
George F
GF
Gao
1] Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada, R3E 0J9 [2] Special Pathogens Program, Canadian Science Center for Human and Animal Health, Public Health Agency of Canada, Winnipeg, Canada, R3E 3R2 [3] Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada, R3E 0J9 [4] Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
Gary
G
Kobinger
Special Pathogens Program, Canadian Science Center for Human and Animal Health, Public Health Agency of Canada, Winnipeg, Canada, R3E 3R2.
Xiangguo
X
Qiu
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D046129:Ebola Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D029043:Ebolavirus / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015870:Gene Expression; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology; D019142:Hemorrhagic Fever, Ebola / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D006801:Humans; D057131:Immune Evasion; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment; D018116:Vesiculovirus / Q000235:genetics; D014759:Viral Envelope Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000936:Antigen-Antibody Complex; D046129:Ebola Vaccines; D000939:Epitopes; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; C485184:enhanced green fluorescent protein; C113189:envelope glycoprotein, Ebola virus; D049452:Green Fluorescent Proteins