Glycoprotein E2 of bovine viral diarrhea virus expressed in insect cells provides calves limited protection from systemic infection and disease

Calves were vaccinated with a C-terminally truncated baculovirus expression product of E2 from the Singer strain of bovine viral diarrhea virus. The expressed E2 was glycosylated and retained antigenic authenticity. After induction of viral neutralizing antibody, the calves were challenge exposed with either the homologous Singer strain of virus or with the heterologous 890 strain of virus. Vaccine-induced antibody titer of greater than or equal to 2 protected calves from clinical signs of disease induced by homologous viral challenge exposure. An antibody titer of greater than or equal to 512 reduced replication of homologous challenge virus to a level which did not induce an appreciable increase in serologic titer of viral neutralizing antibody. Vaccine-induced antibody titer of less than or equal to 4096 did not protect calves from systemic spread of virus or from disease after challenge exposure with heterologous bovine viral diarrhea virus.