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Complex Formation Between Secretory Component and Human Immunoglobulins Related to Their Content of J Chain
Author(s) -
BRANDTZAEG P.
Publication year - 1976
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.1365-3083.1976.tb00295.x
Subject(s) - j chain , dithiothreitol , monomer , chemistry , polymer , antibody , immunoglobulin light chain , bivalent (engine) , chain (unit) , secretory component , immunoglobulin a , biochemistry , chromatography , immunoglobulin g , organic chemistry , enzyme , biology , immunology , metal , physics , astronomy
The J‐chain content of 3 IgM and 24 IgA preparations was quantitated by an immunochemical technique after reduction with 20mM dithiothreitol. The amounts released ranged from undetectable (less than 0.1 mg) to 7.3 mg per 100 mg of Ig. Most of the J‐chain‐deficient proteins were monomeric, but four polymeric IgA preparations were found to contain only 0.2–0.8 mg of J chain per 100 mg. The SC‐binding capacity of these polymers, expressed as percentage of the amount added (2.5 μg SC/100 μg Ig), was 6%–12% compared with 69%–82% for IgA and IgM polymers that contained more than 4.0 mg of J chain per 100 mg. Some monomeric IgA preparations showed a slight SC‐binding capacity, which was explained by the presence of contaminating J‐chain‐positive polymers. Bound J chain therefore seems to be a structural prerequisite for a specific noncovalent complexing of Ig polymers with SC.