Recombinant chimeric bovine/human parainfluenza virus 3 expressing RSV G and its use
Inventors
Collins, Peter L. • Buchholz, Ursula J. • Liang, Bo • Munir, Shirin
Assignees
US Department of Health and Human Services
Publication Number
US-11273214-B2
Publication Date
2022-03-15
Expiration Date
2038-05-29
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Abstract
Recombinant chimeric bovine/human parainfluenza virus 3 (rB/HPIV3) vectors expressing Respiratory Syncytial Virus (RSV) G protein or a recombinant RSV G protein, as well as methods of their use and manufacture, are provided. The rB/HPIV3 vector comprises a genome comprising a heterologous gene encoding the RSV G protein or the recombinant RSV G protein. Nucleic acid molecules comprising the sequence of the genome or antigenome of the disclosed rB/HPIV3 vectors are also provided. The disclosed rB/HPIV3 vectors can be used, for example, to induce an immune response to RSV and HPIV3 in a subject.
Core Innovation
This disclosure provides recombinant chimeric bovine/human parainfluenza virus 3 (rB/HPIV3) vectors expressing Respiratory Syncytial Virus (RSV) G protein or recombinant RSV G protein variants, designed to induce an immune response to RSV and HPIV3. The rB/HPIV3 vector comprises a genome arranged 3′ to 5′ including a BPIV3 N gene, a heterologous gene encoding RSV G protein or recombinant variants thereof, BPIV3 P and M genes, HPIV3 F and HN genes, a BPIV3 L gene, and a 5′ trailer region. Variants include RSV G protein fused with transmembrane and cytoplasmic tail domains derived from BPIV3 HN, HPIV3 HN, or HPIV1 HN proteins. These rB/HPIV3 vectors are infectious, attenuated, and self-replicating.
The problem addressed is the need for a safe and effective immunogen capable of inducing a protective immune response to RSV and HPIV3, particularly in pediatric subjects. Despite the significant burden of RSV and HPIV3 infections, especially in infants and compromised individuals, vaccine development remains elusive due to factors such as immaturity of the infant immune system, interference from maternal antibodies, inefficient protection at respiratory epithelia, and vaccine-enhanced disease observed with inactivated or subunit vaccines. Prior live-attenuated rB/HPIV3 vectors expressing RSV F protein showed disappointing immunogenicity, highlighting the need for improved RSV antigen delivery systems.
The disclosed rB/HPIV3-RSV G vectors express RSV G protein or recombinant variants that maintain important immunogenic domains such as the CX3C motif and can be codon-optimized for expression in human cells. These vectors show efficient replication in vitro and induce robust serum RSV-neutralizing antibody titers, comparable to wild-type RSV infection yet delivered in an attenuated viral context. Packaging of RSV G protein into the vector virions is enhanced by substituting the RSV G transmembrane and cytoplasmic tail domains with those from parainfluenza virus HN proteins, promoting increased surface expression and immunogenicity. The immunogenicity and protective efficacy of the vectors were demonstrated in animal models, showing induction of immune responses neutralizing RSV and HPIV3 and providing protection against RSV challenge.
Claims Coverage
The patent includes one independent claim defining a recombinant chimeric bovine/human parainfluenza virus 3 (rB/HPIV3) vector with specific genome composition and heterologous RSV G protein encoding features.
Genome composition with heterologous RSV G gene insertion
The rB/HPIV3 comprises a genome arranged 3′ to 5′ including a BPIV3 N gene, a heterologous gene encoding an RSV G protein or recombinant variants, BPIV3 P and M genes, HPIV3 F and HN genes, a BPIV3 L gene, and a 5′ trailer region.
Heterologous gene encoding recombinant RSV G protein with specified transmembrane and cytoplasmic tail domains
The heterologous gene encodes one of: (a) recombinant RSV G protein with RSV G ectodomain, BPIV3 HN transmembrane domain and cytoplasmic tail; (b) recombinant RSV G protein with RSV G ectodomain, HPIV3 HN transmembrane domain and cytoplasmic tail; or (c) recombinant RSV G protein with RSV G ectodomain, HPIV1 HN transmembrane domain and cytoplasmic tail, each as disclosed by specific SEQ ID NOs or at least 90% identical thereto.
HPIV3 HN gene encoding HN protein with specific amino acid residues at positions 263 and 370
The HPIV3 HN gene encodes a HPIV3 HN protein comprising threonine and proline residues at amino acid positions 263 and 370, according to SEQ ID NO: 7.
Infectious, attenuated, and self-replicating rB/HPIV3 vectors
The recombinant B/HPIV3 viruses of the invention are infectious, attenuated, and capable of self-replication.
The claims collectively cover rB/HPIV3 vectors containing a heterologous gene encoding recombinant RSV G proteins with defined transmembrane and cytoplasmic tail domains from BPIV3, HPIV3, or HPIV1 HN proteins, an HPIV3 HN gene carrying specified amino acid residues, and describe vectors that are infectious, attenuated, and self-replicating.
Stated Advantages
The disclosed rB/HPIV3-RSV G vectors induce titers of serum RSV-neutralizing antibodies comparable to those induced by wild-type RSV infection.
Inclusion of RSV G protein results in highly effective neutralizing antibodies that block RSV infection in a human airway epithelium model, indicating improved vaccine efficacy.
Substitution of RSV G transmembrane and cytoplasmic tail domains with those from PIV HN proteins enhances packaging of RSV G into virions, potentially increasing antigen exposure and immune response.
Vectors demonstrate efficient replication in vitro and attenuation in vivo, balancing safety and immunogenicity for pediatric vaccine use.
Codon-optimization of the RSV G gene enhances protein expression and immunogenicity in human cells.
Documented Applications
Use of rB/HPIV3 vectors expressing RSV G protein to induce an immune response to RSV and HPIV3 in subjects, including humans particularly between 1 and 18 months of age.
Intranasal administration of immunogenic compositions comprising rB/HPIV3-RSV G vectors to elicit protective immunity.
Development of vaccines targeting RSV and HPIV3 respiratory infections, especially useful in pediatric populations prone to severe lower respiratory tract disease.
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