title: Evaluation of immuno efficiency of hemorrhagic septicemia vaccine strain (vaccine seed).
abstract: OBJECTIVE
  To compared seed culture of hemorrhagic septicemia (HS) bacteria which was used to produce vaccine for its antibody induction efficiency before and after passaging in natural host (calf) using laboratory animals.
  
  
  METHODS
  Serial dilution of virulent bacteria was injected in to mice which were immunized with HS vaccine which was obtained from seed bacteria before and after back passaged in calf. Ratio of survived and dead was calculated by Reed-Meunch hypothesis and the LD50 value for each vaccine trial groups were calculated.
  
  
  RESULTS
  The immunological study revealed that vaccine prepared from back passaged seed culture showed greater improvement in its immunopotency than seed vaccine (before back passage). Around 200 mice were used to study the immuno efficiency of vaccine. Each mouse was from the same source, which were free from the Pastuerella infection previous to expose to trial infection. The same broth culture of HS was used to induce infection in mice in both trials (vaccine before back passage and vaccine after back passage). The 0.2 mL of broth dilution from 10(-1) to 10(-10) was used, as dilution increases, death rate decreases. It indicates the minimum load of bacterium is required to induced infection.
  
  
  CONCLUSIONS
  Obtained results revealed that back passaged vaccine seed HS bacteria in its natural host had provided better immune efficiency to the culture than laboratory stock culture, and this findings recommended that regular annual back passage was mandatory for the vaccine seed culture of Pastuerella multocida bacteria for better establishment of immune potent vaccines.
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Maheswarappa
authors.initials: M
authors.lastname: Gowrakkal
authors.affiliation: Department of Animal Genetics and Breeding, Veterinary College, KVAFSU, Hebbal, Bengaluru, India.
authors.forename: M
authors.initials: M
authors.lastname: Chandrashekar
authors.affiliation: Department of Animal Genetics and Breeding, Veterinary College, KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Shankarappa
authors.initials: S
authors.lastname: Bhajantri
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Jaykumar
authors.initials: J
authors.lastname: Satav
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Gc
authors.initials: G
authors.lastname: Chandakala
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Asha
authors.initials: A
authors.lastname: Mayanna
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: Sm
authors.initials: S
authors.lastname: Byregowda
authors.affiliation: Institute of Animal Health and Veterinary Biologicals (IAH&VB), KVAFSU, Hebbal, Bengaluru, India.
authors.forename: C
authors.initials: C
authors.lastname: Renukaprasad
keywords: Annual vaccination; Hemorrhagic septicemia; LD50 values; Laboratory animals; Natural host