Soluble antigen of bovine viral diarrhea virus

Summary Complement-fixing (CF) soluble antigen (SA) was detectable intra-cellularly prior to the appearance of infectious NADL-MD bovine viral diarrhea (BVD) virus during synthesis in roller flask cultures of bovine embryonic kidney cells. The release of infective virus into the extracellular fluid was concomitant with the release of SA.The SA was separated from the infective virus by sedimentation in a sucrose density gradient and by DEAE-cellulose chromatography.The SA was heat labile at 56° C, but stable in buffers at pH 5, 7, and 9 at 37° C. The SA was irreversibly precipitated in buffers at pH of 3 or below.Trypsin and -chymotrypsin completely inactivated the SA, whereas ribonuclease and deoxyribonuclease had no detectable effect on the CF activity.There was no apparent CF or neutralizing relationship between the SA and infectious NADL-MD BVD virus and arbovirus group B and lymphocytic choriomeningitis virus antisera.