T-cell populations responsive to bovine respiratory syncytial virus in seronegative calves.
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.
Sandbulte
Matthew R
MR
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, 2156 Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Roth
James A
JA
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
D000914:Antibodies, Viral; D014765:Viral Vaccines