Publication Date:
2012-08-31
Description:
Influenza viruses take a yearly toll on human life despite efforts to contain them with seasonal vaccines. These viruses evade human immunity through the evolution of variants that resist neutralization. The identification of antibodies that recognize invariant structures on the influenza haemagglutinin (HA) protein have invigorated efforts to develop universal influenza vaccines. Specifically, antibodies to the highly conserved stem region of HA neutralize diverse viral subtypes. These antibodies largely derive from a specific antibody gene, heavy-chain variable region IGHV1-69, after limited affinity maturation from their germline ancestors, but how HA stimulates naive B cells to mature and induce protective immunity is unknown. To address this question, we analysed the structural and genetic basis for their engagement and maturation into broadly neutralizing antibodies. Here we show that the germline-encoded precursors of these antibodies act as functional B-cell antigen receptors (BCRs) that initiate subsequent affinity maturation. Neither the germline precursor of a prototypic antibody, CR6261 (ref. 3), nor those of two other natural human IGHV1-69 antibodies, bound HA as soluble immunoglobulin-G (IgG). However, all three IGHV1-69 precursors engaged HA when the antibody was expressed as cell surface IgM. HA triggered BCR-associated tyrosine kinase signalling by germline transmembrane IgM. Recognition and virus neutralization was dependent solely on the heavy chain, and affinity maturation of CR6261 required only seven amino acids in the complementarity-determining region (CDR) H1 and framework region 3 (FR3) to restore full activity. These findings provide insight into the initial events that lead to the generation of broadly neutralizing antibodies to influenza, informing the rational design of vaccines to elicit such antibodies and providing a model relevant to other infectious diseases, including human immunodeficiency virus/AIDS. The data further suggest that selected immunoglobulin genes recognize specific protein structural 'patterns' that provide a substrate for further affinity maturation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lingwood, Daniel -- McTamney, Patrick M -- Yassine, Hadi M -- Whittle, James R R -- Guo, Xiaoti -- Boyington, Jeffrey C -- Wei, Chih-Jen -- Nabel, Gary J -- Intramural NIH HHS/ -- England -- Nature. 2012 Sep 27;489(7417):566-70. doi: 10.1038/nature11371. Epub 2012 Aug 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-3005, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22932267" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Antibodies, Neutralizing/*chemistry/genetics/*immunology
;
Antibodies, Viral/chemistry/*genetics/*immunology
;
Antibody Affinity/immunology
;
Binding Sites, Antibody/immunology
;
Complementarity Determining Regions/chemistry/immunology
;
Cross Reactions/immunology
;
Humans
;
Immunoglobulin G/chemistry/immunology
;
Immunoglobulin Heavy Chains/chemistry/immunology
;
Immunoglobulin M/chemistry/immunology
;
Influenza Vaccines/immunology
;
Models, Molecular
;
Molecular Sequence Data
;
Orthomyxoviridae/chemistry/*classification/*immunology
;
Protein Conformation
;
Receptors, Antigen, B-Cell/chemistry/immunology
;
Sequence Alignment
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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