Neutralizing antibody titers against field strains of bovine viral diarrhea virus after vaccination with three commercial vaccines

Abstract

Modified killed vaccines against bovine viral diarrhea virus (BVDV) are used worldwide. In the present study, the cross-neutralization antibody responses against field strains from seven subgenotypes of BVDV-1 and one subgenotype of BVDV-2 were evaluated using sera obtained by three inactivated commercial vaccines. One vaccine contained both BVDV-1 and BVDV-2 strains, while the others contained only BVDV-1a. Three vaccine groups, each containing five calves, were vaccinated two times with 30-day intervals. The antibody titers were evaluated by virus neutralization assay. The monovalent vaccine induced the highest antibody titers. Significant levels of neutralizing antibody titers were maintained up to the last sampling time. Although one vaccine contained the BVDV-2 strain, the lowest antibody titers were detected against field strains from BVDV-2, BVDV-1b, and BVDV-1r. This study indicated that cross-protective immune responses with the most common international BVDV vaccine strains need to be evaluated with challenge experiments against field strains for efficient protection.