Substitutions-modified prefusion RSV F proteins and their use
Inventors
Kwong, Peter • Graham, Barney • Mascola, John • Ou, Li • Druz, Aliaksandr • Chen, Man • Kong, Wing-pui • Georgiev, Ivelin Stefanov • Rundlet, Emily • Joyce, Michael Gordon • Tsybovsky, Yaroslav • Thomas, Paul • Pancera, Marie • Sastry, Mallika • Soto, Cinque • Van Galen, Joseph • Stewart-Jones, Guillaume • Yang, YongPing • Zhang, Baoshan • Baxa, Ulrich
Assignees
US Department of Health and Human Services
Publication Number
US-11174292-B2
Publication Date
2021-11-16
Expiration Date
2037-03-29
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Abstract
Embodiments of a recombinant Respiratory Syncytial Virus (RSV) F ectodomain trimer stabilized in a prefusion conformation are provided. Also disclosed are nucleic acids encoding the RSV F ectodomain trimer and methods of producing the RSV F ectodomain trimer. Methods for inducing an immune response in a subject are also disclosed. In some embodiments, the method can be a method for treating or preventing a RSV infection in a subject by administering a therapeutically effective amount of the recombinant RSV F ectodomain trimer to the subject.
Core Innovation
Embodiments of a recombinant Respiratory Syncytial Virus (RSV) F ectodomain trimer stabilized in a prefusion conformation are provided, along with nucleic acids encoding the RSV F ectodomain trimer and methods of producing it. Methods for inducing an immune response and for treating or preventing RSV infection by administering a therapeutically effective amount of the recombinant RSV F ectodomain trimer to a subject are also disclosed.
The problem being solved is improving RSV vaccines to elicit a greater protective immune response. RSV is a leading cause of severe respiratory diseases, especially in infants and the elderly. Existing vaccines and immunogens, like DS-Cav1, induce neutralizing immune responses but may not elicit responses sufficient to prevent the most severe RSV disease or for maternal immunization protocols that provide passive immunity to infants. Therefore, new RSV F immunogens are needed with enhanced immunogenicity and improved stability attributes.
The invention discloses RSV F-based immunogens developed through iterative structure-based design cycles that increase RSV-protective titers about 4-fold compared to prior immunogens like DS-Cav1. These novel immunogens include genetically linked F1 and F2 subunits with the fusion peptide deleted, DS-Cav1 substitutions, and additional stabilizing mutations such as inter-protomer disulfide bonds to restrict the RSV F ectodomain to its prefusion conformation. Besides enhanced immunogenicity, the immunogens exhibit superior attributes including elimination of the requirement for furin cleavage and more than 10-fold increased antigenic stability to heat inactivation at 60° C. Thus, the recombinant RSV F proteins provide a superior combination of immunogenicity and stability and can be used to induce protective immune responses in pregnant subjects to provide passive immunity to infants for at least six months after birth.
Claims Coverage
The patent includes one independent claim and related dependent claims that cover a recombinant RSV F ectodomain trimer, nucleic acids encoding it, vectors, compositions, host cells, methods of production, and methods of inducing an immune response.
Recombinant RSV F ectodomain trimer stabilized in prefusion conformation
The recombinant RSV F ectodomain trimer comprises three recombinant F2-F1 ectodomain protomers each having a deletion of RSV F positions 104-144 and a glycine-serine peptide linker linking RSV F positions 103 and 145. The protomers include amino acid substitutions of S190F and V207L, a non-native disulfide bond introduced by S155C and S290C substitutions, and a non-native inter-protomer disulfide bond introduced by A149C and Y458C substitutions. The protomers have amino acid sequences corresponding to residues 26-474 or 31-479 of certain SEQ ID NOs. The trimer is stabilized in a prefusion conformation comprising antigenic site Ø, which specifically binds prefusion-specific antibodies.
Linkage to a C-terminal trimerization domain
The recombinant F2-F1 protomers are each linked to a C-terminal trimerization domain, such as a T4 Fibritin trimerization domain comprising the sequence GYIPEAPRDGQAYVRKDGEWVLLSTF (SEQ ID NO: 66). The trimerization domain can be linked to RSV F positions 511, 513, or 523 of the protomers, optionally via a peptide linker, to promote trimerization and stabilization.
Nucleic acids, vectors, host cells, and methods of production for the recombinant trimer
Isolated nucleic acid molecules encoding the recombinant F2-F1 ectodomain protomer of the trimer and vectors, including viral vectors encoding the nucleic acid, are claimed. Host cells comprising such vectors and methods involving expression of the nucleic acid in host cells to produce and purify the recombinant RSV F ectodomain trimer are also covered.
Immunogenic compositions and methods of inducing immune response
Immunogenic compositions comprising the recombinant RSV F ectodomain trimer and methods of administering an effective amount of the trimer to induce an immune response to RSV F protein in subjects, including humans and cattle, are claimed. Methods include administering to pregnant subjects to provide passive immunity to infants. Embodiments also cover virus-like particles comprising the recombinant trimer and the trimer linked to a transmembrane domain for membrane anchoring.
Overall, the claims cover recombinant RSV F ectodomain trimers stabilized in a prefusion conformation by specific amino acid substitutions and disulfide bonds, their nucleic acids and vectors, compositions including them, methods of producing them, and their use in inducing immune responses in subjects.
Stated Advantages
The novel RSV F immunogens increase RSV-protective titers approximately 4-fold above prior immunogens such as DS-Cav1.
They eliminate the requirement for furin cleavage during production.
They exhibit increased antigenic stability to heat inactivation, with several embodiments over 10-fold more stable than DS-Cav1 at 60° C.
They retain prefusion conformation including antigenic site Ø and binding to prefusion-specific antibodies, enhancing immunogenicity.
Documented Applications
Use of recombinant RSV F ectodomain trimers as immunogens to induce an immune response to respiratory syncytial virus (RSV) in subjects, including humans and cattle.
Use of the immunogens in therapeutic and prophylactic methods to treat, inhibit, or prevent RSV infection.
Maternal immunization to induce immunity in pregnant subjects, conferring passive immunity to infants born from the subject and protecting infants during their most vulnerable period.
Formulation of the recombinant RSV F ectodomain trimers in immunogenic compositions, including with adjuvants, protein nanoparticles, and virus-like particles for vaccination.
Use in prime-boost vaccination protocols combining different RSV F subtype antigens or delivery vectors.
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