The present invention provides attenuated P. multocida strains that elicit an immune response in animal P. multocida, compositions comprising said strains, methods of vaccination against P. multocida, and kits for use with such methods and compositions. The invention further provides novel, genetically-engineered mutations in P. multocida hyaD and nanPU genes, which are useful in the production of novel attenuated P. multocida bacterial strains.

The present disclosure describes deoptimized foot and mouth viruses and their use for prophylactic and therapeutic treatment of mammalian subjects. The recombinant viruses provided herein include alterations in several genomic regions as well as Differentiating Infected from Vaccinated Animals (DIVA) markers.

The present disclosure describes deoptimized foot and mouth viruses and their use for prophylactic and therapeutic treatment of mammalian subjects. The recombinant viruses provided herein include alterations in several genomic regions as well as Differentiating Infected from Vaccinated Animals (DIVA) markers.

A method of producing purified FMDV VLPs, comprising contacting cells containing FMDV VLPs with a lysis buffer and allowing the cells to lyse, the lysis buffer comprising 10-20 mM Tris-HCl, 150-200 mM NaCl, 3 mM MgCl.sub.2, and 1% Triton X-100, wherein the lysis buffer does not contain EDTA; centrifuging a solution; and removing a supernatant from the solution, the supernatant containing the purified FMDV VLPs.

A method of producing purified FMDV VLPs, comprising contacting cells containing FMDV VLPs with a lysis buffer and allowing the cells to lyse, the lysis buffer comprising 10-20 mM Tris-HCl, 150-200 mM NaCl, 3 mM MgCl.sub.2, and 1% Triton X-100, wherein the lysis buffer does not contain EDTA; centrifuging a solution; and removing a supernatant from the solution, the supernatant containing the purified FMDV VLPs.

The disclosure is directed to an isolated polynucleotide encoding a modified picornavirus 3C protease, wherein the modified picornavirus 3C protease includes an altered secondary structure and one or more amino acid substitution(s) located at one or more amino acid position(s) corresponding to positions 16-25, 99-100 and 115-130 of a wild-type Fool-and-Mouth Disease Virus (FMDV) 3C protease, wherein the isolated polynucleotide encoding the modified picornavirus 3C protease, when transformed into and co-expressed in a host cell, enhances transgene expression of a P1 precursor polypeptide in comparison to an amount of P1 precursor polypeptide transgene expression exhibited in a host cell transformed and co-expressed with a control picornavirus 3C protease, wherein the one or more corresponding amino acid position(s) is/are identified by an alignment of the modified picornavirus 3C protease with the one or more of the wild type FMDV 3C protease(s). Methods for processing a picornavirus P1 precursor polypeptide into picornavirus viral proteins and/or virus-like particles using the isolated polynucleotides are also provided.

The disclosure is directed to an isolated polynucleotide encoding a modified picornavirus 3C protease, wherein the modified picornavirus 3C protease includes an altered secondary structure and one or more amino acid substitution(s) located at one or more amino acid position(s) corresponding to positions 16-25, 99-100 and 115-130 of a wild-type Fool-and-Mouth Disease Virus (FMDV) 3C protease, wherein the isolated polynucleotide encoding the modified picornavirus 3C protease, when transformed into and co-expressed in a host cell, enhances transgene expression of a P1 precursor polypeptide in comparison to an amount of P1 precursor polypeptide transgene expression exhibited in a host cell transformed and co-expressed with a control picornavirus 3C protease, wherein the one or more corresponding amino acid position(s) is/are identified by an alignment of the modified picornavirus 3C protease with the one or more of the wild type FMDV 3C protease(s). Methods for processing a picornavirus P1 precursor polypeptide into picornavirus viral proteins and/or virus-like particles using the isolated polynucleotides are also provided.

The present invention provides a Hansenula engineering fungus that efficiently expresses CA10 virus-like particles and use thereof. The engineering fungus comprises a recombinant vector carrying P1 and 3CD genes of the CA10 virus, and the starting strain of the engineering fungus is uracil auxotroph. The Hansenula AU-0501, P1 and 3CD genes are optimized according to preferred codons of Hansenula. The present invention also provides a preparation method of CA10 virus-like particles, comprising: culturing engineering fungi, expressing CA10 virus-like particles, and separating and purifying virus-like particles by ultrafiltration and three-step chromatography. The CA10 virus-like particles provided by the present invention and the vaccine prepared therefrom have good immunogenicity, safety and biological activity, the process is simple, the chromatography method is adopted for purification, and large-scale preparation and purification can be realized to obtain a VLP protein stock solution with high purity (greater than 99%), which can be used to prepare a vaccine to prevent CA10 infection, with good economic value and application prospects.

The present invention provides a Hansenula engineering fungus that efficiently expresses CA10 virus-like particles and use thereof. The engineering fungus comprises a recombinant vector carrying P1 and 3CD genes of the CA10 virus, and the starting strain of the engineering fungus is uracil auxotroph. The Hansenula AU-0501, P1 and 3CD genes are optimized according to preferred codons of Hansenula. The present invention also provides a preparation method of CA10 virus-like particles, comprising: culturing engineering fungi, expressing CA10 virus-like particles, and separating and purifying virus-like particles by ultrafiltration and three-step chromatography. The CA10 virus-like particles provided by the present invention and the vaccine prepared therefrom have good immunogenicity, safety and biological activity, the process is simple, the chromatography method is adopted for purification, and large-scale preparation and purification can be realized to obtain a VLP protein stock solution with high purity (greater than 99%), which can be used to prepare a vaccine to prevent CA10 infection, with good economic value and application prospects.

A method of producing purified FMDV VLPs, comprising contacting cells containing FMDV VLPs with a lysis buffer and allowing the cells to lyse, the lysis buffer comprising 10-20 mM Tris-HCl, 150-200 mM NaCl, 3 mM MgCl.sub.2, and 1% Triton X-100, wherein the lysis buffer does not contain EDTA; centrifuging a solution; and removing a supernatant from the solution, the supernatant containing the purified FMDV VLPs.