Stabilized group 2 influenza hemagglutinin stem region trimers and uses thereof
Inventors
BOYINGTON, Jeffrey C. • Graham, Barney S. • Mascola, John R. • YASSINE, Hadi M. • CORBETT, Kizzmekia S. • MOIN, Syed M. • Wang, Lingshu • Kanekiyo, Masaru
Assignees
US Department of Health and Human Services
Publication Number
US-11338033-B2
Publication Date
2022-05-24
Expiration Date
2037-09-01
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Abstract
Vaccines that elicit broadly protective anti-influenza antibodies. The vaccines comprise nanoparticles that display HA trimers from Group 2 influenza virus on their surface. The nanoparticles are fusion proteins comprising a monomeric subunit (e.g., ferritin) joined to stabilized stem regions of Group 2 influenza virus HA proteins. The fusion proteins self-assemble to form the HA-displaying nanoparticles. Also provided are fusion proteins, and nucleic acid molecules encoding such proteins, and assays using nanoparticles of the invention to detect anti-influenza antibodies.
Core Innovation
The invention provides vaccines that elicit broadly protective anti-influenza antibodies by using nanoparticles displaying stabilized hemagglutinin (HA) trimers from Group 2 influenza viruses on their surfaces. These nanoparticles are fusion proteins comprising a monomeric subunit, such as ferritin, joined to stabilized stem regions of Group 2 influenza HA proteins. The fusion proteins self-assemble into nanoparticles which present the HA trimers in a pre-fusion conformation that mimics the native state, thus enhancing immunogenicity.
The problem addressed by the invention is the need for an efficacious influenza vaccine that provides robust protection against Group 2 influenza viruses and offers broad protection against evolving seasonal and pandemic influenza virus strains. Traditional influenza vaccines mainly target the highly variable HA globular head, resulting in strain-specific immunity that is ineffective against antigenically drifted or shifted viruses. The conserved HA stem region offers a promising alternative target, but is poorly immunogenic in its natural state. Existing vaccine approaches using virus-like particles and recombinant HA proteins face manufacturing limitations and inadequate induction of broadly neutralizing antibodies. The invention aims to overcome these challenges by engineering stabilized stem-only HA proteins fused to monomeric subunits to form nanoparticles eliciting broadly protective immune responses.
Claims Coverage
The claims define multiple inventive features related to nanoparticles and fusion proteins comprising Group 2 influenza HA proteins with specific structural modifications, including head region replacement with linker sequences and stem region stabilization.
Nanoparticles displaying stabilized Group 2 influenza HA stem regions with extended helix A
Nanoparticles comprise fusion proteins of a monomeric subunit protein joined to a Group 2 influenza virus HA protein where at least 95% of the HA head region amino acids are replaced with a linker sequence. The helix A in the HA stem region is extended by addition of helix-forming residues improving fusion protein stability. The fusion protein has an amino acid sequence at least 80% identical to SEQ ID NO: 49.
Replacement of inter-helix loop with a linker sequence
The inter-helix loop in the stem region of the HA protein is replaced with a linker sequence to further stabilize the protein conformation.
Stabilizing mutations forming or strengthening ionic interactions or salt bridges
The stem region includes one or more mutations that form or strengthen ionic interactions or salt bridges within the HA protein to improve stability.
Mutations increasing hydrophobic packing in the HA stem region
The stem region comprises one or more mutations that enhance hydrophobic packing to enhance fusion protein structural integrity.
Use of specific monomeric subunit proteins
The monomeric subunit protein is selected from ferritin or lumazine synthase monomeric subunit proteins.
Specific fusion protein sequences
The fusion protein includes amino acid sequences set forth as SEQ ID NO: 49, including the extension of helix A by five helix-forming amino acid residues.
The claims collectively cover nanoparticles and fusion proteins where the head region of Group 2 influenza HA is largely replaced by linkers, helix A is extended, and stabilizing mutations are incorporated, with ferritin or lumazine synthase as monomeric subunits to form stable, immunogenic nanoparticles useful as vaccines.
Stated Advantages
The vaccine is easily manufactured.
The vaccine is potent and elicits antibodies that are broadly heterosubtypic protective.
Documented Applications
Use as vaccines to immunize individuals against infection by Group 2 influenza virus, eliciting broadly protective antibodies.
Use in methods of vaccinating individuals to prevent or reduce pathological effects of influenza virus infection.
Use in immunoassays for detecting anti-influenza antibodies in biological samples using the disclosed nanoparticles.
Use in the development of assays that detect and quantify anti-influenza antibody responses for diagnosis or monitoring immune responses.
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