“Protein A” from Staphylococcus Aureus

Abstract

Protein A of Staphylococcus aureus precipitates in agar gel normal rabbit γG-globulin and a rabbit anti-protein A γG preparation. In both cases there seem to be reactive regions located in the Fc fragments of the γG-globulin molecule, i.e., structural parts which currently are not believed to contain true antibody active sites. We did not observe a reaction between protein A and the Fab fragments of normal rabbit γG-globulin or rabbit anti-protein A. It is possible that soluble complexes were formed which were not detectable by the methods used.