Immune responses of lambs to the fusion (F) glycoprotein of bovine respiratory syncytial virus expressed on insect cells infected with a recombinant baculovirus.

A group of lambs was immunized with the F protein of bovine respiratory syncytial virus expressed in a baculovirus (Bac-F) and their humoral and cellular immune responses to bovine RSV studied before and after challenge with infectious bovine RSV. Immunization with Bac-F resulted in significant humoral immune responses as measured by virus neutralization and cellular immune responses as measured by lympho-proliferation against inactivated bovine RSV and specific cytotoxicity against autologous targets. Challenge infection with bovine RSV was characterized by significant anamnestic responses in Bac-F immunized lambs and virus shedding in nasal secretions was significantly lower in Bac-F immunized lambs than in control lambs.