Enzyme-linked immunosorbent assay assessment of bovine viral diarrhea virus antigen in inactivated vaccines using polyclonal or monoclonal antibodies.

An enzyme-linked immunosorbent assay (ELISA) procedure was developed to assay the cytopathic and noncytopathic bovine viral diarrhea (BVD) virus strains used in inactivated vaccines licensed by the United States Department of Agriculture. The assay uses a biotin-labeled, staphylococcal protein A purified polyclonal BVD antibody (Bab) from a calf hyperimmuned against NADL, Singer, C24v, New York-1 (NY-1) strains and a field isolate. The Bab recognized the following reference strains of BVD virus: NADL; NY-1; C24v; Singer; and a field isolate. Monoclonal antibodies (Mab) directed against gp48 and gp53 of the Singer strain of BVD could detect only the Singer and the NY-1 strains. None of the Mab tested could differentiate between cytopathic and noncytopathic BVD virus strains. In vaccines containing multiple viral and bacterial components, the Bab was specific for the BVD fraction. Two vaccines not recognized by the Bab differed from the others in the type of adjuvant. The formation of antigen-adjuvant complexes during vaccine production may inhibit the ability of Bab to detect BVD antigens in an ELISA format. This ELISA procedure enables the detection of BVD antigens and demonstrates the potential for in vitro testing of inactivated BVD vaccines in place of the currently required host animal testing.