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 fev er'', an acute bronchopneumonia brought on in part by a complex of bov ine respiratory viruses, remains a major source of economic loss in th e 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 hemagglutin in/neuraminidase (HN) protein of bovine parainfluenza virus type-3 (BP IV-3) expressed in the baculovirus expression system. We showed that t he 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 biol ogical activity of the expressed HN protein. Finally, we vaccinated co lostrum deprived sero-negative calves with the baculoHN recombinant pr otein and challenged with BPIV-3. Vaccination induced excellent serum neutralizing antibody responses, and surprisingly, good mucosal antibo dy responses, even though the vaccine was administered parenterally. T he vaccinated animals were well protected against challenge. (C) 1997 Elsevier Science Ltd.