title: Immunity studies in  calves vaccinated with a multivalent live respiratory vaccine composed of I.B.R., parainfluenza 3 and bovine adenovirus type 3.
abstract: The persistence of systemic and local antibodies was studied after two intranasal administrations of the vaccine, six weeks apart. Systemic antibodies to I.B.R. and adenovirus 3 evoked by the vaccine were still present 21 weeks following the second dose of the vaccine. Inconslusive results were obtained regarding the persistence of systemic and local PI-3 antibodies because of an intercurrent natureal PI-3 infection occurring during the observation period. Local antibodies to adenovirus type 3 were found in a high percentage of vaccinated animals 21 weeks after the second  dose of the vaccine, whereas local antibodies to I.B.R. remained detectable in 50% of the animals eight weeks after thesecond  dose. The results of a challenge study 21 weeks after revaccination show that the presence of local and systemic antibodies prevent the multiplication of PI-3 and BAV-3 in the upper respiratory tract. Protection against I.B.R. was achieved in the absence of detectable local antibodies.
mesh_terms: D000256:Adenoviridae / Q000276:immunology*; D000281:Administration, Intranasal; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D002417:Cattle / Q000276:immunology*; D007242:Herpesvirus 1, Bovine / Q000276:immunology*; D007109:Immunity; D009093:Mucus / Q000276:immunology; D009666:Nose; D010224:Parainfluenza Virus 3, Human / Q000276:immunology*; D018184:Paramyxoviridae Infections / Q000517:prevention & control / Q000662:veterinary; D018108:Respirovirus / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage*
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines