Immunization of cattle with a BHV1 vector vaccine or a DNA vaccine both coding for the G protein of BRSV.

A gE-negative bovine herpesvirus 1 (BHV1) vector vaccine carrying a gene coding for the G protein of bovine respiratory syncytial virus (BRSV) (BHV1/BRSV-G) induced the same high degree of protection in calves against BRSV infection and BHV1 infection as a multivalent commercial vaccine. A DNA plasmid vaccine, carrying the same gene as the BHV1/BRSV-G vaccine, significantly reduced BRSV shedding after BRSV infection compared with that in control calves, but less well than the BHV1/BRSV-G vaccine. Flow cytometric analysis showed a significant relative increase of gamma/delta+ T cells in peripheral blood after BRSV challenge-infection of the calves of the control group but not in the vaccinated groups. These results indicate that the G protein of BRSV can induce significant protection against BRSV infection in cattle, and that the BHV1/BRSV-G vaccine protects effectively against a subsequent BRSV and BHV1 infection.