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FURTHER CHARACTERIZATION OF PROTEIN A REACTIVE AND NON‐REACTIVE SUBFRAGMENTS OF Fc FROM HUMAN IgG
Author(s) -
ENDRESEN C.,
GROV A.
Publication year - 1976
Publication title -
acta pathologica microbiologica scandinavica section c immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0304-1328
DOI - 10.1111/j.1699-0463.1976.tb00047.x
Subject(s) - chemistry , sephadex , size exclusion chromatography , immunodiffusion , immunoglobulin fc fragments , rheumatoid factor , microbiology and biotechnology , fragment crystallizable region , gel electrophoresis , antigen , polyacrylamide gel electrophoresis , electrophoresis , radial immunodiffusion , biochemistry , immunoglobulin g , antibody , biology , enzyme , immunology , receptor
Tryptic digests of acid‐treated Fc from normal human IgG were separated into four peaks (I‐IV) by gel filtration on Sephadex G‐100. The second peak was further divided into two fractions (II and II'). Peak I was indistinguishable from intact Fc on electrophoresis, immunodiffusion, and reactivity to protein A. The protein A reactive fragments of fractions II, II', and III were shown to contain antigenic determinants of both the C H 2 and C H 3 domains, to interact with the anti‐Gm (1) specific rheumatoid factor, and to fix complement. These results, together with SDS‐electrophoresis, showed that protein A reactive fragments are all composed of an intact Fc chain with shorter chains covalently linked to it. The protein A non‐reactive fragments of fractions II' and III were homogeneous, fixed complement and showed no interaction with the Gm (1) rheumatoid factor. These results, in addition to the observed antigenic determinants, localized the fragments to the C H 2 region.