Candidate vaccine antigens and genes in Pasteurella multocida

Area of Science:

• Veterinary Microbiology
• Bacteriology
• Vaccine Development

Background:

• Pasteurella multocida causes significant diseases in production animals, including fowl cholera.
• Current vaccines offer limited protection, often only against homologous serotypes.
• Existing live attenuated vaccines have risks of reversion to virulence.

Purpose of the Study:

• To identify novel protective antigens and virulence factors of Pasteurella multocida.
• To develop improved vaccine candidates for enhanced protection against diverse serotypes.
• To elucidate the genetic basis of Pasteurella multocida virulence and host-pathogen interactions.

Main Methods:

• Gene cloning and sequencing of outer membrane protein (Oma87) and type 4 fimbrial subunit (PtfA).
• Characterization of the capsule biosynthetic locus and identification of relevant genes (bex genes).
• Cloning and characterization of the transferrin binding protein (Tbp1) and esterase (MesA) genes.

Main Results:

• Recombinant Oma87 conferred passive protection in mice.
• Type 4 fimbriae were identified, and their gene (ptfA) will be inactivated to assess virulence.
• Capsule biosynthesis genes and transferrin binding protein gene were cloned and characterized.
• A novel hemolytic phenotype under anaerobic conditions was linked to the mesA gene.

Conclusions:

• Identification of Oma87 and PtfA provides potential targets for new vaccine strategies.
• Understanding capsule biosynthesis and iron acquisition mechanisms can inform virulence attenuation.
• Investigating novel virulence factors like MesA contributes to a comprehensive understanding of pathogenesis.