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Comparison of Mechanisms of Interaction between Protein A from Staphylococcus aureus and Human Monoclonal IgG, IgA and IgM in Relation to the Classical Fcγ and the Alternative F(ab') 2 γ Protein A Interactions
Author(s) -
INGANÄS M.
Publication year - 1981
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.1365-3083.1981.tb00143.x
Subject(s) - subclass , myeloma protein , protein a , protein a/g , sepharose , immunoglobulin e , antibody , protein g , microbiology and biotechnology , monoclonal antibody , chemistry , fragment crystallizable region , binding protein , staphylococcus aureus , biology , biochemistry , immunology , recombinant dna , enzyme , gene , fusion protein , bacteria , genetics
Four purified human monoclonal IgG, IgA and IgM proteins were tested for their Inhibitor; effect on the binding of protein‐A‐reactive 125 I‐IgE and 125 I‐Fcγ. respectively, to protein‐A‐Sepharose. Only IgG myeloma proteins significantly inhibited the binding of 125 I‐Fcγ to protein‐A‐Sepharose, whereas most, but not all, myeloma proteins, irrespective of their immunoglobulin class and with varying efficiency, inhibited the binding of protein‐A‐reactive 125 I‐IgE to protein‐A‐Sepharose. The inhibitory effect of IgG and IgA proteins on the binding of protein‐A‐reactive 125 I‐IgE was retained in the respective F(ab') 2 fragments, whereas the Inhibitory effect of IgG proteins on the binding of 125 I‐Fcγ to protein‐A Sepharose was exclusively expressed in the Fey fragment. In addition to the classical Fcγ‐protein A interaction, the results indicate the existence of a common and variably expressed protein A reactivity in at least four of five human immunoglobulins, The data suggest that an interaction with protein A cannot be used as a criterion for subclass differentiation of IgA and IgM.