title: T-cell populations responsive to bovine respiratory syncytial virus in seronegative calves.
abstract: Calves lacking detectable serum antibodies against bovine respiratory syncytial virus (BRSV) were screened for virus-specific T-cell memory. Peripheral blood mononuclear cells were cultured in vitro with live BRSV and analyzed by dual-color flow cytometry for surface expression of CD25 on CD4(+), CD8(+), and gammadeltaT-cells. Significant recall responses were detected in some of the seronegative calves. Modified live BRSV vaccine was administered to these and to a group of non-responding calves. Following vaccination, virus-specific IgG, virus neutralizing antibody, and T-cell recall responses were all elevated more rapidly in the group with BRSV-sensitive T-cells than in the T-cell-negative group, which suggested that calves in the first group were previously exposed to BRSV. This demonstrates that exposure to BRSV can induce T and B cell memory in young calves without causing seroconversion. The calves were presumably exposed to BRSV while they had maternal antibody, which inhibited the calves from developing an antibody response.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, 2156 Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Sandbulte
authors.forename: James A
authors.initials: JA
authors.lastname: Roth
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D002478:Cells, Cultured; D007114:Immunization; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines