The disclosure relates to defective interfering viruses and defective interfering virus RNAs that are effective as antiviral agents. The disclosure also relates to methods for identifying defective interfering virus RNAs that can be used as effective antiviral agents.

The present disclosure discloses a whole avian-origin reverse genetic system, a recombinant H5N2 subtype avian influenza virus, a vaccine containing the virus, and a preparation method and application thereof. The genome of the recombinant virus is comprised of a modified HA gene derived from a highly pathogenic H5N6 subtype avian influenza virus strain, as well as PB2, PB1, PA, NP, NA, M and NS genes derived from H5N2 subtype avian influenza D7 virus strain. The recombinant virus is a recombinant H5N2 avian influenza virus rescued from the D7 virus strain as a backbone, which is an avirulent virus strain with the original immunogenicity, and can maintain a high virus titer during the chick embryo culture process. The recombinant virus fully meets the biological safety requirements and has a good application prospect.

This invention provides an attenuated virus which comprises a modified viral genome containing nucleotide substitutions engineered in multiple locations in the genome, wherein the substitutions introduce synonymous deoptimized codons into the genome. The instant attenuated virus may be used in a vaccine composition for inducing a protective immune response in a subject. The invention also provides a method of synthesizing the instant attenuated virus. Further, this invention further provides a method for preventing a subject from becoming afflicted with a virus-associated disease comprising administering to the subject a prophylactically effective dose of a vaccine composition comprising the instant attenuated virus.

Provided is a proteolysis-targeting virus, wherein one or more proteolysis-targeting molecules that can be recognized by the ubiquitin-proteasome system are comprised at one or more different sites of protein thereof, and the viral protein is linked to the proteolysis-targeting molecules by one or more linkers that can be selectively cleaved. Also provided are a nucleic acid molecule encoding the proteolysis-targeting virus, a nucleic acid vector expressing the proteolysis-targeting virus, a preparation method for the proteolysis-targeting virus, methods for the preparation of an attenuated live virus, replication-incompetentlive virus, replication-controllable live virus, and a relevant vaccine and medication for preventing and treating virus infections, a vaccine or pharmaceutical composition comprising the proteolysis-targeting virus, and a system for preparing the proteolysis-targeting virus.

The present invention provides, among other things, a novel and improved method for generating “mosaic” influenza antigenic polypeptides including hemagglutinin (HA) and neuraminidase (NA) polypeptides based on unique combination of epitope patterns that maximize exposure to epitopes present across multiple HA or NA sequences and therefore improved influenza strain coverage. In particular, the present invention provides engineered H1N1 influenza hemagglutinin (HA) polypeptides that are comprised of novel combinations of protective epitopes and antigenic regions from multiple H1N1 viral strains. Such engineered HA polypeptides have improved properties over HA polypeptides developed through conventional approaches that rely on consensus alignments of viral sequences.

Provided is a recombinant H7N9 subtype avian influenza virus, a marked vaccine and a preparation method thereof. For the recombinant H7N9 subtype avian influenza virus, a strain JD/17 of H7N9 subtype avian influenza virus is used as parent virus and a peptide sequence in HA protein of the strain JD/17 is replaced with a peptide sequence in HA protein of H3 subtype; the strain JD/17 of H7N9 subtype avian influenza virus has a preservation number of CCTCC No. V201862. The results of HA titers, EID50, TCID50 show that the rescued virus maintains similar biological characteristics of parent virus, such as high HA titers and EID50, and chickens immunized with the marked inactivated and emulsified vaccine produce a high level of antibody, and this antibody can be distinguished from antibodies produced by chickens naturally infected with H7N9 subtype avian influenza virus.

The present invention includes a live, self-attenuated therapeutic vaccine, virus and methods of making and using the same, comprising: an isolated virus comprising a viral genome that expresses one or more viral antigens; and an artificial microRNA 30 (amiR-30) expression cassette inserted into a viral neuraminidase (NA) or a viral non-structural (NS) gene segment that expresses an amiR-30 that specifically inhibits the expression of a host gene essential for influenza virus replication in host cells.

Compositions and methods are provided for a live, attenuated influenza vaccine suitable for nasal administration. The vaccine utilizes a cold adapted influenza virus that lacks virulence factor, and includes mutations that provide replicative ability sufficient for vaccine manufacture. Vaccines so produced provide significant cross protection for non-vaccinating strains. The vaccine is safe for children under the age of 2 and adults over 49 years of age. In addition, the cold adapted, virulence factor deleted influenza virus can be adapted to provide immunity to non-influenza pathogens.

Provided is a recombinant H7N9 subtype avian influenza virus, a marked vaccine and a preparation method thereof. For the recombinant H7N9 subtype avian influenza virus, a strain JD/17 of H7N9 subtype avian influenza virus is used as parent virus and a peptide sequence in HA protein of the strain JD/17 is replaced with a peptide sequence in HA protein of H3 subtype; the strain JD/17 of H7N9 subtype avian influenza virus has a preservation number of CCTCC No. V201862. The results of HA titers, EID50, TCID50 show that the rescued virus maintains similar biological characteristics of parent virus, such as high HA titers and EID50, and chickens immunized with the marked inactivated and emulsified vaccine produce a high level of antibody, and this antibody can be distinguished from antibodies produced by chickens naturally infected with H7N9 subtype avian influenza virus.

The present invention includes a live, self-attenuated therapeutic vaccine, virus and methods of making and using the same, comprising: an isolated virus comprising a viral genome that expresses one or more viral antigens; and an artificial microRNA 30 (amiR-30) expression cassette inserted into a viral neuraminidase (NA) or a viral non-structural (NS) gene segment that expresses an amiR-30 that specifically inhibits the expression of a host gene essential for influenza virus replication in host cells.