The Fc Binding Regions in Protein A are not Responsible for the Polyclonal B Cell Activating Property of Protein A

Abstract

To test whether the polyclonal B cell activating property of protein A is due to its ability to bind to the Fc part of immunoglobulins, experiments were carried out with purified monomeric or dimeric Fc-binding fragments of protein A. Neither monomeric nor dimeric fragments induced polyclonal antibody synthesis in vitro, whereas intact protein A was a strong activator. It is concluded that the Fc binding part of protein A is not responsible for activation of polyclonal antibody synthesis.