title: Effect of passively-acquired antibodies and vaccination on the immune response to contagious ecthyma virus.
abstract: Lambs which received colostrum from ewes vaccinated with contagious ecthyma (CE) virus and other lambs vaccinated with CE virus were compared for serum anti-CE immunoglobulin (Ig)G levels, delayed-type hypersensitivity (DTH) responses to CE viral antigen, and protective immunity to challenge with CE virus. Ewes vaccinated 3-4 weeks prior to parturition transferred CE antibody to lambs via colostrum. Although these lambs had higher levels of antibody at challenge than lambs vaccinated when 1-4 days old, only the vaccinated lambs were protected against challenge with CE virus at 1 month of age. Furthermore, the presence of colostrum-derived maternal antibody prevented an active antibody response in lambs to vaccination and/or challenge with CE virus, except where pre-inoculation titres were low. In contrast, the DTH response to CE viral antigen and induction of protective immunity by CE vaccination were not impaired by passively-acquired antibody. Actively immunised lambs could be distinguished from those only receiving passively-acquired antibody by the DTH response to heat-killed CE viral antigen.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis*; D003126:Colostrum / Q000276:immunology; D004474:Ecthyma, Contagious / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006968:Hypersensitivity, Delayed; D007112:Immunity, Maternally-Acquired; D009923:Orf virus / Q000276:immunology*; D011212:Poxviridae / Q000276:immunology*; D012756:Sheep; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines