Proteins separated from human IgG molecules.
Immunoglobulin G binding proteins were separated from human IgG molecules using 1 N acetic acid followed by 5 M guanidinium chloride in 0.1 M acetic acid. The proteins thus obtained were heterogeneous as demonstrated by SDS-PAGE and reverse-phase HPLC. The isolated proteins consisted of two types: the C3a and C4a complement fragments (anaphylatoxins) and immunoglobulin peptide chain fragments V kappa I and C gamma 3. Both anaphylatoxins immobilized on cellulose nitrate membranes could reassociate with intact IgG molecules. The ubiquitous presence of C3a in IgG preparations was demonstrated using monoclonal antibodies specific for C3a. Nearly all of the bound anaphylatoxin molecules were found in the Fab fragment. These findings suggest that IgG molecules can eliminate anaphylatoxins from the circulation, and thus prevent harmful effects due to these active complement components.
Nezlin
R
R
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
Freywald
A
A
Oppermann
M
M
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D015926:Complement C3a / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D015934:Complement C4a / Q000737:chemistry / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D015151:Immunoblotting; D007128:Immunoglobulin Fragments / Q000737:chemistry* / Q000302:isolation & purification; D007074:Immunoglobulin G / Q000737:chemistry*; D008969:Molecular Sequence Data; D009103:Multiple Sclerosis / Q000276:immunology; D017386:Sequence Homology, Amino Acid
D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D015926:Complement C3a; D015934:Complement C4a