The invention relates to an attenuated variant of the Rift Valley Fever Virus (RVFV) with mutations in the amino acid sequence coded by segments L, M and S of RVFV RNA; a pharmaceutical or veterinary composition comprising same; an attenuated RVFV variant for use in the prevention of Rift Valley Fever; and a vaccine against Rift Valley Fever comprising the attenuated RVFV variant. Attenuated RVFV variants with the mutations Gly924Ser and Ala303Thr in protein L, and the Pro82Leu substitution in protein NSs, are also included.

Certain embodiments are directed to an improved RVF vaccine for human use, and method for producing the same.

The present invention relates to enveloped RNA viruses. The invention in particular relates to the generation of superior antigens for mounting an immune response by first identifying then mutating the immunosuppressive domains in fusion proteins of enveloped RNA viruses resulting in decreased immunosuppressive properties of viral envelope proteins from the viruses.

Certain embodiments are directed to an improved RVF vaccine for human use, and method for producing the same.

Provided herein are isolated exosomes. An exome can include a nonstructural (NSs) protein of a virus, a glycoprotein (Gn protein) of a virus, or a combination thereof. The virus is a member of the Order Bunyavirales, such as a member of the genus Phlebovirus. In one embodiment, the virus is Severe Fever with Thrombocytopenia Syndrome (SFTS) virus. Also provided are methods for making and using the exosomes described herein.

This invention provides an attenuated virus comprising a modified viral genome engineered to containing multiple nucleotide substitutions that reduce the codon pair bias of a virus protein encoding sequence relative to a first host while the codon pair bias relative to a second host is not substantially reduced. In another embodiment, the invention provides an attenuated virus comprising modified viral genome engineered to containing multiple nucleotide substitutions that reduce the codon pair bias of a virus protein-encoding sequence relative to a first host and a second host. The 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 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 attenuated virus.

The present invention relates to enveloped RNA viruses. The invention in particular relates to the generation of superior antigens for mounting an immune response by first identifying then mutating the immunosuppressive domains in fusion proteins of enveloped RNA viruses resulting in decreased immunosuppressive properties of viral envelope proteins from the viruses.

This invention provides an attenuated virus comprising a modified viral genome engineered to containing multiple nucleotide substitutions that reduce the codon pair bias of a virus protein encoding sequence relative to a first host while the codon pair bias relative to a second host is not substantially reduced. In another embodiment, the invention provides an attenuated virus comprising modified viral genome engineered to containing multiple nucleotide substitutions that reduce the codon pair bias of a virus protein-encoding sequence relative to a first host and a second host. The 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 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 attenuated virus.

Described herein are recombinant RVF viruses comprising deletions in one or more viral virulence genes, such as NSs and NSm. The recombinant RVF viruses, generated using a plasmid-based reverse genetics system, can be used as vaccines to prevent infection of RVF virus in livestock and humans. As described herein, the recombinant RVF viruses grow to high titers, provide protective immunity following a single injection and allow for the differentiation between vaccinated animals and animals infected with wild-type RVF virus.

Provided herein are isolated exosomes. An exome can include a nonstructural (NSs) protein of a virus, a glycoprotein (Gn protein) of a virus, or a combination thereof. The virus is a member of the Order Bunyavirales, such as a member of the genus Phlebovirus. In one embodiment, the virus is Severe Fever with Thrombocytopenia Syndrome (SFTS) virus. Also provided are methods for making and using the exosomes described herein.