Pasteurella multocida strains and vaccines having hyaC and nanP deletions
Inventors
Briggs, Robert E • Tatum, Fred M
Assignees
US Department of Agriculture USDA
Publication Number
US-12071636-B2
Publication Date
2024-08-27
Expiration Date
2041-09-17
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Abstract
The present invention provides novel attenuated Pasteurella multocida strains that may be used, in live or killed form, to formulate vaccines that are highly protective against P. multocida infection in bovines, other mammals, and in birds. The present invention also identifies the combination of nanP and hyaC gene mutations as key to the provision of such vaccines. When appropriately formulated, antigenic material of numerous other bovine pathogens may be combined with the live attenuated Pasteurella multocida strains, to make effective combination vaccines.
Core Innovation
The invention provides novel attenuated Pasteurella multocida strains that contain mutations in the hyaC and nanP genes. These mutations result in bacteria defective for biosynthesis of hyaluronic acid and surface sialylation, respectively, leading to substantial reduction in virulence. These attenuated strains can be used in live or killed form to formulate vaccines that protect against P. multocida infections in bovines, other mammals, and birds. The invention also encompasses methods of producing such strains and their use in combination vaccines with other bovine pathogen antigens.
The problem addressed is that Pasteurella multocida is a major cause of Bovine Respiratory Disease (BRD), a multi-factorial illness involving multiple bacterial and viral pathogens. Existing vaccines based on single gene mutations such as in nanP provide attenuation but may lack optimal safety and efficacy. Thus, mutations in multiple genes, specifically in hyaC and nanP, are identified as key to improving vaccine safety by achieving stronger attenuation while maintaining protective immunity.
Claims Coverage
The patent includes ten claims featuring two independent claims covering attenuated Pasteurella multocida bacteria with mutations in hyaC and/or nanP genes, providing live or killed vaccine strains with specific genetic characteristics.
Attenuation via hyaC or nanP gene mutations
An attenuated Pasteurella multocida bacterium with a mutated hyaC gene encoding a non-functional polypeptide of SEQ ID NO:11 or a polypeptide at least 80% identical thereto, or with a mutated nanP gene encoding a polypeptide unable to uptake sialic acid having the amino acid sequence of SEQ ID NO:4 or at least 80% identical thereto.
Serogroup inclusivity
The bacterium can be assigned to capsular Serogroup A, B, D, E, or F, expanding applicability against multiple P. multocida types.
Specific gene sequences
The mutated nanP gene can comprise the nucleotide sequence of SEQ ID NO:3 or at least 80% identical thereto, and the mutated hyaC gene can comprise the nucleotide sequence of SEQ ID NO:12 or at least 80% identical thereto.
Live or killed bacterial forms
The attenuated bacterium may be used in live form or killed form, suitable for vaccine formulations.
Double mutation for enhanced attenuation
A strain comprising both a mutated hyaC gene encoding non-functional polypeptide SEQ ID NO:11, and a mutated nanP gene encoding the polypeptide unable to uptake sialic acid of SEQ ID NO:4.
Broad polypeptide identity for gene variants
An attenuated bacterium comprising hyaC and nanP genes encoding polypeptides at least 80% identical over the length common with SEQ ID NO:11 and SEQ ID NO:4, respectively, broadened to homologous variants.
The claims collectively cover attenuated P. multocida strains with mutations in either or both hyaC and nanP genes that encode specific polypeptides or close variants, covering live and killed forms applicable to multiple serogroups. These claims protect the mutated gene sequences, polypeptides, and combination mutants useful for vaccine development.
Stated Advantages
The attenuated bacteria provide strong immune responses and cross-protection against diverse P. multocida serogroups relevant worldwide.
Attenuation involving mutations in both hyaC and nanP genes enhances safety by more effectively reducing virulence compared to single gene mutations.
The invention allows for combination vaccines with antigens from other important bovine pathogens, facilitating multivalent vaccination.
The diafiltration/wash process used in vaccine preparation improves safety post-vaccination by reducing adverse reactions.
Documented Applications
Use as live or killed vaccines to protect bovines, other mammals, and birds against infection by Pasteurella multocida.
Formulation into multicomponent vaccines combined with antigens from bovine pathogens including Mannheimia haemolytica, Bovine Diarrhea Virus, Bovine Rhinotracheitis Virus, Parainfluenza 3 Virus, Bovine Respiratory Syncytial Virus, Bovine Corona Virus, Mycoplasma bovis, Histophilus somni, and Clostridial species.
Intranasal or subcutaneous administration of the attenuated strains as vaccine treatments in calves and other cattle.
Use in combination vaccines such as Bovishield Gold-One Shot® and Bovishield GOLD FP5 VL5 HB®, which protect against multiple viral and bacterial diseases affecting cattle.
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