ANTIGENIC SIMILARITIES AMONG BIOTIN-BINDING PROTEINS

Using polyclonal antisera to avidin, streptavidin, and biotin binding protein-II (BBP-II), the extents of immunological cross-reactivities s hared by this family of biotin-binders were investigated. In Western b lot analysis, varying degrees of cross-reactivities among these protei ns depending on the antisera used was observed. Using liquid phase rad ioimmunoassay, evidence for the existence of common antigenic determin ants shared by all the biotin-binders was deduced. Antibodies directed against such epitopes inhibited the binding of [H-3]biotin to as well as displace the bound ligand from all the three high affinity biotin- binders in a dose dependent manner.