title: Onset of immunity with Mycoplasma synoviae: comparison of the live attenuated vaccine MS-H (Vaxsafe MS) with its wild-type parent strain (86079/7NS).
abstract: The onset of protective immunity with MS-H was determined through experimental challenge and compared with the parent strain 86079/7NS. MS-H vaccinates and 86079/7NS inoculates were challenged at 1, 2, 3, 4, 5, and 6 wk after vaccination, then examined 2 wk after challenge for signs of respiratory disease. Serologic results indicated that 100% of MS-H vaccinates had antibodies to MS by 3 wk after vaccination and 100% of 86079/7NS inoculates were positive by 2 wk after inoculation. From 3 wk after vaccination, MS-H vaccinates had a significantly lower incidence of air sac lesions and, from 4 wk after vaccination, a significantly lower air sac lesion severity. In 86079/7NS-inoculated birds, a significantly lower incidence of air sac lesions was observed from 1 wk after inoculation, and air sac lesion severity was significantly lower than the unvaccinated controls at 3 wk after inoculation. It would appear that, under the conditions of this experiment, protective immunity elicited by MS-H appeared at 4 wk after vaccination, slightly later than the appearance of serum antibody. Although the MS-H vaccine was slower to establish protective immunity than 86079/7NS, there was no significant difference between the two strains by 4 wk after vaccination or inoculation.
authors.affiliation: School of Veterinary Science, The University of Melbourne, Werribee, Victoria, 3030, Australia.
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Jones
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Whithear
authors.forename: Peter C
authors.initials: PC
authors.lastname: Scott
authors.forename: Amir H
authors.initials: AH
authors.lastname: Noormohammadi
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D014644:Genetic Variation; D009175:Mycoplasma Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D045805:Mycoplasma synoviae / Q000145:classification* / Q000276:immunology*; D020545:Respiratory Mucosa / Q000473:pathology; D013047:Specific Pathogen-Free Organisms; D014132:Trachea / Q000473:pathology; D014613:Vaccines, Attenuated / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated