Influenza A viruses exhibit extreme diversity as exemplified by the multiple serotypes of the hemagglutinin (HA, H1-H18) and neuraminidase (NA, N1-N11) surface antigens. To date, only three of the possible 198 combinations of HA and NA in avian and other animal reservoirs have been associated with human pandemics (H1N1, H2N2, H3N2). However, ever increasing anxiety about pandemic threats stemming from influenza viruses of zoonotic origins have heightened concern about emergence of a human transmissible virus that could devastate the human population. The recent appearance of H5N1, H6N1, H7N7, H7N9, H9N2, and H10N8 viruses in the human population are constant reminders of this possibility. Influenza B viruses with their two distinct lineages further increase the health and economic burden of seasonal influenza worldwide. In this proposal, we aim to elucidate, at the structural level, key sites of vulnerability on influenza virus and incorporate the essential information on how antibodies and receptor analogs target these sites into structure- based design, development, and synthesis of novel therapeutics. Antibody-mediated neutralization of influenza virus is a complex combinatorial problem for the human immune system when presented with diverse, highly variable and constantly evolving viruses. While neutralizing antibodies against human flu are traditionally regarded as being strain specific, recent advances have shown that much broader responses can be mounted and provided us with valuable new insights into conserved sites of vulnerability. We are amassing compelling evidence that a sustained, cross-serotype response can be mounted against influenza and this vital information can now be harnessed for design of small molecules, peptides, and proteins to target these key sites of vulnerability, thereby blocking influenza infection. No effective drugs are currently available for preventing entry of influenza virus. As a proof-of-concept of our approach, we have determined the crystal structure of umifenovir (an antiviral for influenza infection used in Russia and China) in complex with HA and exploited this structural information to synthesize a derivative with 100x improved binding. We will elucidate common features for recognition of these sites of vulnerability in pandemic and emerging influenza viruses from crystal structures of diverse HAs with broadly neutralizing antibodies as well as sialosides that are mimics of the natural receptor. A combined biophysical, biochemical, and chemical approach employing state-of-the- art structural biology, yeast-display evolution, and chemical biology will be harnessed to design and synthesize small molecules as novel therapeutic candidates to control and combat the threat of future influenza pandemics as well as seasonal epidemics.

Public Health Relevance

How sites of vulnerability on influenza virus can be targeted will be determined from structural studies of influenza hemagglutinin in complex with broadly neutralizing antibodies, natural sialoside receptors and receptor analogs. Recurring recognition motifs will provide a platform and strong foundation for design of small molecules, peptides, and small proteins, as therapeutic candidates to prevent influenza virus infection and pandemic threats.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
High Priority, Short Term Project Award (R56)
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Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
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Krafft, Amy
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Scripps Research Institute
La Jolla
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Kadam, Rameshwar U; Wilson, Ian A (2018) A small-molecule fragment that emulates binding of receptor and broadly neutralizing antibodies to influenza A hemagglutinin. Proc Natl Acad Sci U S A 115:4240-4245
Zost, Seth J; Wu, Nicholas C; Hensley, Scott E et al. (2018) Immunodominance and antigenic variation of influenza virus hemagglutinin: implications for design of universal vaccine immunogens. J Infect Dis :
Guan, Wenda; Yang, Zifeng; Wu, Nicholas C et al. (2018) Clinical Correlations of Transcriptional Profile in Patients Infected With Avian Influenza H7N9 Virus. J Infect Dis 218:1238-1248
Wu, Nicholas C; Yamayoshi, Seiya; Ito, Mutsumi et al. (2018) Recurring and Adaptable Binding Motifs in Broadly Neutralizing Antibodies to Influenza Virus Are Encoded on the D3-9 Segment of the Ig Gene. Cell Host Microbe 24:569-578.e4
Credille, Cy V; Dick, Benjamin L; Morrison, Christine N et al. (2018) Structure-Activity Relationships in Metal-Binding Pharmacophores for Influenza Endonuclease. J Med Chem 61:10206-10217
Laursen, Nick S; Friesen, Robert H E; Zhu, Xueyong et al. (2018) Universal protection against influenza infection by a multidomain antibody to influenza hemagglutinin. Science 362:598-602
Wu, Nicholas C; Thompson, Andrew J; Xie, Jia et al. (2018) A complex epistatic network limits the mutational reversibility in the influenza hemagglutinin receptor-binding site. Nat Commun 9:1264
Wu, Nicholas C; Wilson, Ian A (2018) Structural insights into the design of novel anti-influenza therapies. Nat Struct Mol Biol 25:115-121
Lang, Shanshan; Xie, Jia; Zhu, Xueyong et al. (2017) Antibody 27F3 Broadly Targets Influenza A Group 1 and 2 Hemagglutinins through a Further Variation in VH1-69 Antibody Orientation on the HA Stem. Cell Rep 20:2935-2943
Wright, Zoƫ V F; Wu, Nicholas C; Kadam, Rameshwar U et al. (2017) Structure-based optimization and synthesis of antiviral drug Arbidol analogues with significantly improved affinity to influenza hemagglutinin. Bioorg Med Chem Lett 27:3744-3748

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