Human serum immunoglobulin G3 subclass bound preferentially to asialo-, agalactoimmunoglobulin A1/Sepharose.
As we reported before, exoglycosidase treatment of human serum IgA1 changed it to a sticky molecule. In order to examine the presence of the specific binding protein to the sticky IgA1 in human serum, IgA1, asialo-IgA1 (IgA1-S) and asialo-, agalacto-IgA1 (IgA1-SG)/Sepharose column chromatography of normal human serum was carried out. Purified hinge glycopeptide (HGP33) prepared from IgA1 was used for the preparation of HGP/Sepharose. A portion of the serum protein was bound to those columns and eluted with the buffer containing 1.0 M NaCl. About four times the amount of protein was eluted from the IgA1-SG/Sepharose column than that from IgA1/Sepharose. Most of the eluted protein was IgG, and the IgG1 and IgG3 subclasses but neither IgG2 nor IgG4 was dominant. Under the lower salt concentration, a portion of IgG was also bound to the HGP-SG/Sepharose column. The obtained results coincide well with the previous report of the co-present of IgG1 and IgG3 with deposited IgA1 in IgA nephropathy patients (Aucouturier, P., et al. (1989) Clin. Immunol. Immunopathol. 51, 338-347). Thus, the results solved the question of why the IgG3 was co-present with deposited IgA1 in IgA nephropathy patients.
Iwase
H
H
Department of Biochemistry, Kitasato University, Sagamihara, Kanagawa, 228-8555, Japan. iwaseh@med.kitasato-u.ac.jp
Yokozeki
Y
Y
Hiki
Y
Y
Tanaka
A
A
Kokubo
T
T
Sano
T
T
Ishii-Karakasa
I
I
Hisatani
K
K
Kobayashi
Y
Y
Hotta
K
K
D002853:Chromatography, Liquid / Q000379:methods; D005922:Glomerulonephritis, IGA / Q000276:immunology; D006020:Glycopeptides / Q000737:chemistry; D006026:Glycoside Hydrolases; D006031:Glycosylation; D006801:Humans; D007070:Immunoglobulin A / Q000737:chemistry* / Q000276:immunology; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology; D008222:Lymphokines / Q000737:chemistry / Q000302:isolation & purification; D029584:Prostatic Secretory Proteins
D006020:Glycopeptides; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008222:Lymphokines; D029584:Prostatic Secretory Proteins; C400366:agalactoimmunoglobulin A1; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors; D006026:Glycoside Hydrolases