Comparative assessment of a metabolically attenuated Mycoplasma gallisepticum mutant as a live vaccine for the prevention of avian respiratory mycoplasmosis.
In a previous study, signature sequence mutagenesis (SSM) was used to identify a mutant with a disruption of the gene encoding the metabolic factor, dihydrolipoamide dehydrogenase, and that mutant was designated Mg 7. The current study assessed the safety, immunogenicity and efficacy of Mg 7 in comparison to two commercially available vaccines (ts-11 and F) as well as a laboratory vaccine strain, GT5. Intratracheal vaccination of chickens with all four attenuated mutants induced varying levels of protection against intratracheal challenge with virulent Mycoplasma gallisepticum strain R(low). Mg 7 vaccinated chickens rapidly cleared the challenge strain, had lower histopathologic tracheal lesion scores when compared to unvaccinated chickens, and mounted a strong humoral anti-M. gallisepticum-specific IgG response. The IgG levels increased 2- to 3-fold upon R(low) challenge. Mg 7 induced a greater level of protection against intratracheal R(low) challenge than that observed with the other three attenuated strains, as evidenced by a lower recovery of R(low) from tracheas and lower histopathologic lesion scores in tracheas and air sacs. Based on these findings, Mg 7 appears to have good potential as a safe and effective vaccine for the prevention of avian mycoplasmosis.
Gates
A E
AE
Center of Excellence for Vaccine Research, The University of Connecticut, Storrs, CT 06269, United States.
Frasca
S
S
Nyaoke
A
A
Gorton
T S
TS
Silbart
L K
LK
Geary
S J
SJ
D000400:Air Sacs / Q000473:pathology; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D002645:Chickens; D008058:Dihydrolipoamide Dehydrogenase / Q000235:genetics; D005260:Female; D009154:Mutation; D009175:Mycoplasma Infections / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D045686:Mycoplasma gallisepticum / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D011201:Poultry Diseases / Q000473:pathology / Q000517:prevention & control*; D020545:Respiratory Mucosa / Q000473:pathology; D012141:Respiratory Tract Infections / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D014132:Trachea / Q000473:pathology; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000008:administration & dosage
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; D008058:Dihydrolipoamide Dehydrogenase