title: Macaque Monoclonal Antibodies Targeting Novel Conserved Epitopes within Filovirus Glycoprotein.
abstract: Filoviruses cause highly lethal viral hemorrhagic fever in humans and nonhuman primates. Current immunotherapeutic options for filoviruses are mostly specific to Ebola virus (EBOV), although other members of Filoviridae such as Sudan virus (SUDV), Bundibugyo virus (BDBV), and Marburg virus (MARV) have also caused sizeable human outbreaks. Here we report a set of pan-ebolavirus and pan-filovirus monoclonal antibodies (MAbs) derived from cynomolgus macaques immunized repeatedly with a mixture of engineered glycoproteins (GPs) and virus-like particles (VLPs) for three different filovirus species. The antibodies recognize novel neutralizing and nonneutralizing epitopes on the filovirus glycoprotein, including conserved conformational epitopes within the core regions of the GP1 subunit and a novel linear epitope within the glycan cap. We further report the first filovirus antibody binding to a highly conserved epitope within the fusion loop of ebolavirus and marburgvirus species. One of the antibodies binding to the core GP1 region of all ebolavirus species and with lower affinity to MARV GP cross neutralized both SUDV and EBOV, the most divergent ebolavirus species. In a mouse model of EBOV infection, this antibody provided 100% protection when administered in two doses and partial, but significant, protection when given once at the peak of viremia 3 days postinfection. Furthermore, we describe novel cocktails of antibodies with enhanced protective efficacy compared to individual MAbs. In summary, the present work describes multiple novel, cross-reactive filovirus epitopes and innovative combination concepts that challenge the current therapeutic models.
  
  
  OBJECTIVE
  Filoviruses are among the most deadly human pathogens. The 2014-2015 outbreak of Ebola virus disease (EVD) led to more than 27,000 cases and 11,000 fatalities. While there are five species of Ebolavirus and several strains of marburgvirus, the current immunotherapeutics primarily target Ebola virus. Since the nature of future outbreaks cannot be predicted, there is an urgent need for therapeutics with broad protective efficacy against multiple filoviruses. Here we describe a set of monoclonal antibodies cross-reactive with multiple filovirus species. These antibodies target novel conserved epitopes within the envelope glycoprotein and exhibit protective efficacy in mice. We further present novel concepts for combination of cross-reactive antibodies against multiple epitopes that show enhanced efficacy compared to monotherapy and provide complete protection in mice. These findings set the stage for further evaluation of these antibodies in nonhuman primates and development of effective pan-filovirus immunotherapeutics for use in future outbreaks.
authors.affiliation: Department of Pathology, Stanford University, Stanford, California, USA.
authors.forename: Zhen-Yong
authors.initials: ZY
authors.lastname: Keck
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Sven G
authors.initials: SG
authors.lastname: Enterlein
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Katie A
authors.initials: KA
authors.lastname: Howell
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Vu
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shulenin
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Warfield
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Froude
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Nazli
authors.initials: N
authors.lastname: Araghi
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Douglas
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Biggins
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: Calli M
authors.initials: CM
authors.lastname: Lear-Rooney
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: Ariel S
authors.initials: AS
authors.lastname: Wirchnianski
authors.affiliation: Department of Pathology, Stanford University, Stanford, California, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lau
authors.affiliation: Department of Pathology, Stanford University, Stanford, California, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Herbert
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Dye
authors.affiliation: U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Glass
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA.
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Holtsberg
authors.affiliation: Department of Pathology, Stanford University, Stanford, California, USA.
authors.forename: Steven K H
authors.initials: SK
authors.lastname: Foung
authors.affiliation: Integrated BioTherapeutics, Inc., Gaithersburg, Maryland, USA javad@integratedbiotherapeutics.com.
authors.forename: M Javad
authors.initials: MJ
authors.lastname: Aman
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification / Q000627:therapeutic use; D057134:Antibodies, Neutralizing / Q000276:immunology / Q000302:isolation & purification / Q000627:therapeutic use; D000914:Antibodies, Viral / Q000276:immunology* / Q000302:isolation & purification / Q000627:therapeutic use; D003429:Cross Reactions; D004195:Disease Models, Animal; D000939:Epitopes / Q000276:immunology*; D005260:Female; D016563:Filoviridae / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology*; D019142:Hemorrhagic Fever, Ebola / Q000517:prevention & control*; D007116:Immunization, Passive; D008251:Macaca; D008807:Mice, Inbred BALB C; D016019:Survival Analysis; D016896:Treatment Outcome; D014764:Viral Proteins / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000939:Epitopes; D006023:Glycoproteins; D014764:Viral Proteins