The bovine parainfluenza virus type-3 (BPIV-3) hemagglutinin/neuraminidase glycoprotein expressed in baculovirus protects calves against experimental BPIV-3 challenge.

Despite the availability of numerous vaccine schedules, "shipping fever", an acute bronchopneumonia brought on in part by a complex of bovine respiratory viruses, remains a major source of economic loss in the beef and dairy industries. We are exploring new strategies of bovine vaccine design which we hope may provide more effective and more cost-efficient control of these pathogens. In this report, we examined the possible use of subunit vaccines, using as an example the hemagglutinin/neuraminidase (HN) protein of bovine parainfluenza virus type-3 (BPIV-3) expressed in the baculovirus expression system. We showed that the protein was expressed at high levels, and was modified to a similar, but not identical size as the native HN protein expressed from BPIV-3 infected bovine cells. We further demonstrated antigenicity and biological activity of the expressed HN protein. Finally, we vaccinated colostrum deprived sera-negative calves with the baculo HN recombinant protein and challenged with BPIV-3. Vaccination induced excellent serum neutralizing antibody responses, and surprisingly, good mucosal antibody responses, even though the vaccine was administered parenterally. The vaccinated animals were well protected against challenge.