Vaccine candidates for human respiratory syncytial virus (RSV) having attenuated phenotypes
Inventors
LE NOUEN, Cyril • Buchholz, Ursula J. • Collins, Peter L. • Mueller, Steffen
Assignees
Codagenix Inc • US Department of Health and Human Services
Publication Number
US-12054519-B2
Publication Date
2024-08-06
Expiration Date
2037-09-22
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Abstract
Reported herein are presumptively de-attenuating mutations that are useful, either individually or in combinations that may include other known mutations, in producing recombinant strains of human respiratory syncytial virus (RSV) exhibiting attenuation phenotypes. Also described herein is a novel RSV construct, Min_L-NPM2-1(N88K)L, which exhibits an attenuated phenotype, is stable and is as immunogenic as wild type RSV. The recombinant RSV strains described here are suitable for use as live-attenuated RSV vaccines. Exemplary vaccine candidates are described. Also provided are polynucleotide sequences capable of encoding the described viruses, as well as methods for producing and using the viruses.
Core Innovation
The invention relates to recombinant strains of human respiratory syncytial virus (RSV) that exhibit attenuated phenotypes suitable for use as live vaccines. It discloses presumptively de-attenuating mutations useful individually or in combination with other known mutations that produce RSV exhibiting attenuation in vivo. A novel RSV construct, Min_L-NPM2-1(N88K)L, is described that is genetically stable, highly attenuated in vivo, yet as immunogenic as wild-type RSV.
The problem being solved concerns the difficulties in developing RSV vaccines that are sufficiently attenuated to be safe, yet immunogenic and genetically stable. Existing methods struggle with insufficient attenuation, phenotypic reversion, instability due to genetic drift, and challenges in balancing virus replication for immunogenicity and manufacturability. Prior codon-pair deoptimization (CPD) approaches produced either highly stable but possibly over-attenuated constructs or constructs like Min_L that quickly reverted to escape temperature sensitivity and lost attenuation, showing instability under selective pressure.
Claims Coverage
The independent claims cover isolated polynucleotide molecules encoding recombinant RSV variants having attenuated phenotypes with specific mutations and their uses.
Attenuated RSV variant with L ORF mutation at position T1166
An isolated polynucleotide encodes an RSV variant with an attenuated phenotype comprising a missense mutation in the L open reading frame (ORF) at the amino acid position corresponding to T1166 of the L protein (SEQ ID NO:11).
Additional mutations in M2-1, N, and P ORFs
The RSV genome or antigenome may be further modified by missense mutations selected from the group consisting of mutations in the M2-1 ORF at positions corresponding to N88 (N88K) or A73 (A73S) of the M2-1 protein (SEQ ID NO:9), a mutation in the N ORF at K136 (K136R, SEQ ID NO:3), and a mutation in the P ORF at E114 (E114V, SEQ ID NO:4), alone or in combination. These mutations can be present singly or as combinations.
Deletions and codon-pair deoptimization for attenuation
The RSV genome or antigenome may further comprise deletions in the M2-2, NS1, or NS2 proteins. Additionally, the RSV genome or antigenome, including specifically the L ORF, may be subjected to codon-pair deoptimization to produce attenuation.
Vectors, cells, pharmaceutical compositions, and vaccination methods
Vectors comprising the isolated polynucleotides and cells containing them are claimed. Pharmaceutical compositions including the encoded recombinant RSV variants and methods of vaccinating subjects or inducing immune responses by administering such compositions via intranasal or other delivery routes are also included.
The claims broadly cover polynucleotide molecules encoding recombinant RSV variants attenuated by mutations in the L ORF at T1166 alone or in combination with mutations in M2-1, N, and P ORFs. The claims further encompass deletion mutations, codon-pair deoptimization strategies, and their use in vectors, cells, pharmaceutical compositions, and vaccination methods.
Stated Advantages
Highly attenuated RSV strains that are stable genetically and phenotypically under selective pressure.
Recombinant RSV constructs such as Min_L-NPM2-1[N88K]L are more attenuated in vivo than parental strains yet retain immunogenicity comparable to wild-type RSV.
The vaccine candidates replicate efficiently in vitro, facilitating vaccine manufacture.
The presence of multiple mutations provides genetic stability and resistance to reversion to virulence.
Documented Applications
Use of recombinant RSV strains as live attenuated vaccines against RSV infection in humans.
Pharmaceutical compositions containing these recombinant RSV variants for inducing immune responses in RSV-susceptible subjects.
Methods of vaccination comprising administration of the described pharmaceutical compositions intranasally, by injection, aerosol delivery, nasal spray, or nasal droplets.
Use of the recombinant RSV strains as vectors for protective antigens of other pathogens, particularly for bivalent vaccines with parainfluenza virus antigens.
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