Eliciting a single amino acid change by vaccination generates antibody protection against group 1 and group 2 influenza A viruses

Immunity. 2024 May 14;57(5):1141-1159.e11. doi: 10.1016/j.immuni.2024.03.022. Epub 2024 Apr 25.

Abstract

Broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin (HA) stem of influenza A viruses (IAVs) tend to be effective against either group 1 or group 2 viral diversity. In rarer cases, intergroup protective bnAbs can be generated by human antibody paratopes that accommodate the conserved glycan differences between the group 1 and group 2 stems. We applied germline-engaging nanoparticle immunogens to elicit a class of cross-group bnAbs from physiological precursor frequency within a humanized mouse model. Cross-group protection depended on the presence of the human bnAb precursors within the B cell repertoire, and the vaccine-expanded antibodies enriched for an N55T substitution in the CDRH2 loop, a hallmark of the bnAb class. Structurally, this single mutation introduced a flexible fulcrum to accommodate glycosylation differences and could alone enable cross-group protection. Thus, broad IAV immunity can be expanded from the germline repertoire via minimal antigenic input and an exceptionally simple antibody development pathway.

Keywords: human antibody repertoire; immunogen; influenza virus; somatic hypermutation; universal; vaccine.

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Antibodies, Neutralizing* / immunology
  • Antibodies, Viral* / immunology
  • B-Lymphocytes / immunology
  • Broadly Neutralizing Antibodies / immunology
  • Hemagglutinin Glycoproteins, Influenza Virus / immunology
  • Humans
  • Influenza A virus* / immunology
  • Influenza Vaccines* / immunology
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control
  • Mice
  • Orthomyxoviridae Infections* / immunology
  • Orthomyxoviridae Infections* / prevention & control
  • Vaccination*