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Binding of Murine Myeloma Proteins of Different Ig Classes and Subclasses to Fc‐reactive Surface Structures in Gram‐positive Cocci
Author(s) -
MYHRE E. B.,
KRONVALL G.
Publication year - 1980
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.1365-3083.1980.tb00206.x
Subject(s) - myeloma protein , antibody , protein a , polyclonal antibodies , staphylococcus aureus , immunoglobulin a , subclass , biology , microbiology and biotechnology , streptococcus , immunoglobulin g , immunoglobulin m , protein g , chemistry , immunology , bacteria , genetics
Twelve different murine myeloma proteins were tested for binding to seventy Gram‐positive strains belonging to group A, C and G streptococci and to Staphylococcus aureus. Group A streptococci, known lo hind human IgG. were incapable of binding any of eight murine IgG immunoglobulins tested except for one strain that hound un IgG2b myeloma protein. In contrast, group C and G streptococci interacted with murine immunoglobulins of subclasses IgG2a, IgG2b and IgG3, and G strains also to a lesser extent with IgG1. Bovine and equine group C streptococci did not differ from human group C streptococci in their IgG reactivity. Staphylococcal strains showed a high reactivity with murine myeloma components of IgG subclasses 2a, 2b and 3 and a low but definite binding of an IgG1 myeloma protein. IgA myeloma protein S‐122 interacted with nine of fifteen group A streptococci. This binding could not be inhibited by human IgG and the reactivity is thus different from Fc‐mediated binding of immunoglobulins. One of three IgA myeloma proteins tested, TEPC 15, bound to staphylococci. The Fc specificity of this interaction was confirmed by chromatography on protein A‐Sepharose and by inhibition studies using polyclonal human IgG. The protein A reactivity of this monoclonal protein was detected in IgA aggregates and absent in the monomeric form of IgA.