Induction of antigen-specific T-cell subset activation to bovine respiratory disease viruses by a modified-live virus vaccine.
OBJECTIVE
To determine the efficacy of a modified-live virus vaccine containing bovine herpes virus 1 (BHV-1), bovine respiratory syncytial virus (BRSV), parainfluenza virus 3, and bovine viral diarrhea virus (BVDV) types 1 and 2 to induce neutralizing antibodies and cell-mediated immunity in naïve cattle and protect against BHV-1 challenge.


METHODS
17 calves.


METHODS
8 calves were mock-vaccinated with saline (0.9% NaCl) solution (control calves), and 9 calves were vaccinated at 15 to 16 weeks of age. All calves were challenged with BHV-1 25 weeks after vaccination. Neutralizing antibodies and T-cell responsiveness were tested on the day of vaccination and periodically after vaccination and BHV-1 challenge. Specific T-cell responses were evaluated by comparing CD25 upregulation and intracellular interferon-gamma expression by 5-color flow cytometry. Titration of BHV-1 in nasal secretions was performed daily after challenge. Results-Vaccinated calves seroconverted by week 4 after vaccination. Antigen-specific cell-mediated immune responses, by CD25 expression index, were significantly higher in vaccinated calves than control calves. Compared with control calves, antigen-specific interferon-gamma expression was significantly higher in calves during weeks 4 to 8 after vaccination, declining by week 24. After BHV-1 challenge, both neutralizing antibodies and T-cell responses of vaccinated calves had anamnestic responses to BHV-1. Vaccinated calves shed virus in nasal secretions at significantly lower titers for a shorter period and had significantly lower rectal temperatures than control calves.


CONCLUSIONS
A single dose of vaccine effectively induced humoral and cellular immune responses against BHV-1, BRSV, and BVDV types 1 and 2 and protected calves after BHV-1 challenge for 6 months after vaccination.
Platt
Ratree
R
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, 50011, USA.
Burdett
William
W
Roth
James A
JA
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D030241:Diarrhea Virus 1, Bovine Viral / Q000276:immunology; D030242:Diarrhea Virus 2, Bovine Viral / Q000276:immunology; D007242:Herpesvirus 1, Bovine / Q000276:immunology; D008213:Lymphocyte Activation; D009666:Nose / Q000821:virology; D029101:Parainfluenza Virus 3, Bovine / Q000276:immunology; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*; D014777:Virus Diseases / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*
D000956:Antigens, Viral; D014765:Viral Vaccines