title: Influenza hemagglutinin stem-fragment immunogen elicits broadly neutralizing antibodies and confers heterologous protection.
abstract: Influenza hemagglutinin (HA) is the primary target of the humoral response during infection/vaccination. Current influenza vaccines typically fail to elicit/boost broadly neutralizing antibodies (bnAbs), thereby limiting their efficacy. Although several bnAbs bind to the conserved stem domain of HA, focusing the immune response to this conserved stem in the presence of the immunodominant, variable head domain of HA is challenging. We report the design of a thermotolerant, disulfide-free, and trimeric HA stem-fragment immunogen which mimics the native, prefusion conformation of HA and binds conformation specific bnAbs with high affinity. The immunogen elicited bnAbs that neutralized highly divergent group 1 (H1 and H5 subtypes) and 2 (H3 subtype) influenza virus strains in vitro. Stem immunogens designed from unmatched, highly drifted influenza strains conferred robust protection against a lethal heterologous A/Puerto Rico/8/34 virus challenge in vivo. Soluble, bacterial expression of such designed immunogens allows for rapid scale-up during pandemic outbreaks.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India;
authors.forename: Vamsee V A
authors.initials: VV
authors.lastname: Mallajosyula
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and.
authors.forename: Michael
authors.initials: M
authors.lastname: Citron
authors.affiliation: Viral Pseudotype Unit, Medway School of Pharmacy, University of Kent, Chatham Maritime ME4 4TB, United Kingdom.
authors.forename: Francesca
authors.initials: F
authors.lastname: Ferrara
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and.
authors.forename: Xianghan
authors.initials: X
authors.lastname: Lu
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Callahan
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and.
authors.forename: Gwendolyn J
authors.initials: GJ
authors.lastname: Heidecker
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India;
authors.forename: Siddhartha P
authors.initials: SP
authors.lastname: Sarma
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Flynn
authors.affiliation: Viral Pseudotype Unit, Medway School of Pharmacy, University of Kent, Chatham Maritime ME4 4TB, United Kingdom.
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Temperton
authors.affiliation: Merck Research Laboratories, West Point, PA 19486; and varadar@mbu.iisc.ernet.in liangxiaoping@walvax.com.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Liang
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India; varadar@mbu.iisc.ernet.in liangxiaoping@walvax.com.
authors.forename: Raghavan
authors.initials: R
authors.lastname: Varadarajan
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D003429:Cross Reactions; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D053118:Influenza A Virus, H1N1 Subtype / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D017434:Protein Structure, Tertiary
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus
keywords: Escherichia coli; cross-protection; hemagglutinin stalk; pandemic preparedness; stabilization