Characterization of BK virus‐specific antibodies in human sera by Western immunoblotting: Use of a zwitterionic detergent for restoring the antibody‐binding capacity of electroblotted proteins

Abstract

After initial problems related to denaturation of antigenic epitopes, we developed a Western immunoblotting method for the characterization of antibodies reacting with BK virus (BKV) structural polypeptides. When a zwitterionic detergent, Empigen BB, was added to the running buffer during electroblotting, the antibody‐binding capacity of electrophoretically separated BKV polypeptides was partially restored. Antibodies reacting with different BKV antigens were detected and visualized by biotinylated anti‐species‐specific antibodies, peroxidase‐conjugated streptavidine, and diaminobenzidine staining. Human sera containing anti‐BKV antibodies reacted with VP1, but a serum containing antinuclear antibodies also reacted with VP4, ‐5 and ‐6 (histones). Serum from a rabbit inoculated with purified BKV reacted with VP1, and also with VP4, indicating that BKV inoculation may imply production of antibodies against histones.