title: Effect of maternal antibodies on induction and persistence of vaccine-induced immune responses against bovine viral diarrhea virus type II in young calves.
abstract: OBJECTIVE
  To determine the effect of maternally derived antibodies on induction of protective immune responses against bovine viral diarrhea virus (BVDV) type II in young calves vaccinated with a modified-live bovine viral diarrhea virus (BVDV) type I vaccine.
  
  
  METHODS
  Blinded controlled challenge study.
  
  
  METHODS
  24 neonatal Holstein and Holstein-cross calves that were deprived of maternal colostrum and fed pooled colostrum that contained a high concentration of (n = 6) or no (18) antibodies to BVDV.
  
  
  METHODS
  At 10 to 14 days of age, 6 seropositive and 6 seronegative calves were given a combination vaccine containing modified-live BVDV type I. All calves were kept in isolation for 4.5 months. Six calves of the remaining 12 untreated calves were vaccinated with the same combination vaccine at approximately 4 months of age. Three weeks later, all calves were challenged intranasally with a virulent BVDV type II.
  
  
  RESULTS
  Seronegative unvaccinated calves and seropositive calves that were vaccinated at 2 weeks of age developed severe disease, and 4 calves in each of these groups required euthanasia. Seronegative calves that were vaccinated at 2 weeks or 4 months of age developed only mild or no clinical signs of disease.
  
  
  CONCLUSIONS
  Results indicate that a single dose of a modified-live BVDV type-I vaccine given at 10 to 14 days of age can protect susceptible young calves from virulent BVDV type II infection for at least 4 months, but high concentrations of BVDV-specific maternally derived antibodies can block the induction of the response.
authors.affiliation: Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.forename: K
authors.initials: K
authors.lastname: West
authors.forename: V
authors.initials: V
authors.lastname: Cortese
authors.forename: C
authors.initials: C
authors.lastname: Konoby
authors.forename: D
authors.initials: D
authors.lastname: Weigel
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood* / Q000276:immunology; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000517:prevention & control*; D002417:Cattle; D003126:Colostrum / Q000276:immunology; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology*; D007112:Immunity, Maternally-Acquired; D013997:Time Factors; D014611:Vaccination / Q000662:veterinary; D015164:Vaccines, Inactivated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D015164:Vaccines, Inactivated; D014765:Viral Vaccines