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The Polyclonal B‐Cell‐Activating Property of Protein A Is Not Due to Its Interaction with the Fc Part of Immunoglobulin Receptors
Author(s) -
MÖLLER G.,
LANDWALL P.
Publication year - 1977
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1977.tb00405.x
Subject(s) - polyclonal antibodies , receptor , antibody , protein a , immune system , antiserum , fragment crystallizable region , biology , microbiology and biotechnology , activator (genetics) , b cell , immunoglobulin g , spleen , chemistry , immunology , biochemistry
Protein A from Staphylococcus aureus bacteria was farad to be I B‐cell mitogen and a potent polyclonal B‐cell activator (PBA) of antibody synthesis fur murine lymphocytes in the absence of macrophages or T lymphocytes. It did not activate T lymphocytes. We investigated whether the interaction between protein A and the Fc part of Ig molecules was responsible for the PBA activity. Protein A failed to induce IgG synthesis in spleen cells from normal mice, even though it binds effectively to IgG molecules. Lymphocytes treated with anti‐immune‐globulin antisera followed by protein A were not activated to a larger extent than non‐pretreated cells, although only the former cells bound protein A. Finally, direct attempts to suppress the PBA property of protein A by blocking the Fc binding ability with serum or human gamma globulin foiled We concluded that protein A possesses two separate biological properties, namely to interact with the Fc receptor on Ig molecules and to act as a PBA, and these properties are carried out by different parts of the molecule. These findings confirm previous failures to find an active role of the Ig receptors on B lymphocytes in the triggering process.