The Fab region of IgG2 human myeloma proteins does not bear the streptococcal protein G-specific determinant.
Seven out of ten Fab (F(ab')2/Fab') preparations derived from purified human myeloma IgG showed a substantial binding to protein G-Sepharose. Subclass analysis revealed that the 7 protein G-reactive Fabs included 3 IgG1, 2 IgG3 and 2 IgG4 Fabs, whereas the remaining 3 which were not adsorbed were IgG2 Fab. Incubation of protein G-Sepharose with non-saturating amounts of 4 Fab preparations, representative of all IgG subclasses, showed that gamma 1, gamma 3 and gamma 4 Fabs adsorbed from 26 to 28.3%, whereas 80% of gamma 2 Fab was left in the supernatant after adsorption. These results indicate that human IgG2 lack PG-specific Fab-associated reactive site(s).
Perosa
F
F
Department of Biomedical Sciences and Human Oncology (DIMO), University of Bari Medical School, Italy.
Luccarelli
G
G
Neri
M
M
Dammacco
F
F
D000911:Antibodies, Monoclonal / Q000097:blood / Q000302:isolation & purification; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry*; D002846:Chromatography, Affinity; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry* / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry*; D007163:Immunosorbent Techniques; D009194:Myeloma Proteins / Q000737:chemistry* / Q000276:immunology; D013291:Streptococcus / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D000939:Epitopes; C034284:IgG Fc-binding protein, Streptococcus; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D009194:Myeloma Proteins