Immunology of bovine viral diarrhea virus.

Often persistent and primary postnatal infections with BVDV result in immunosuppression in cattle, thereby enhancing the vulnerability of the latter to secondary infections. The evidence for and nature of impaired immunity in these animals is reviewed. Our knowledge of the extent and nature of protective immunity induced by natural BVDV infections and vaccines is still in its infancy. Significant new information on the bovine immune response to BVDV antigens, however, has been identified in recent years. These data are reviewed and related to prospects for improved immunoprophylaxis against diseases caused by the virus.