Partial biochemical characterization and purification of IgG2b inducing factor as a new cytokine from synovial fluid of patients with rheumatoid arthritis.
Rheumatoid arthritis synovial fluid (RA-SF) contains a novel biological activity, which selectively induces IgG2b antibody production in lipopolysaccharide (LPS)-activated mouse spleen cells in vitro and in vivo. Our previous studies have shown that this activity is not functionally identical to other well-known cytokines and interleukins. In this study we demonstrate the partial purification and biochemical characterization of the IgG2b inducing activity in RA-SF. Biochemical characterization revealed that the IgG2b inducing activity in RA-SF has the following properties: it is a protein, sensitive to pH > 11 and < 4, which is precipitated by 50% of saturated ammonium sulphate and has a molecular weight of 50-70 kDa; it binds to Cibacron-blue and heparin and its activity is not mediated by immunoglobulins or immune complexes, which are present in RA-SF. Biochemical characteristics of the IgG2b inducing activity also differ from other cytokines and interleukins. The term IgG2b inducing factor is proposed for this novel activity.
Abedi-Valugerdi
M
M
Department of Immunology, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden.
Ridderstad
A
A
Ström
H
H
Möller
G
G
Möller
E
E
D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001665:Binding Sites; D016207:Cytokines / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006493:Heparin / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G / Q000096:biosynthesis*; D008970:Molecular Weight; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013582:Synovial Fluid / Q000737:chemistry*; D014227:Triazines / Q000378:metabolism
D016207:Cytokines; D007074:Immunoglobulin G; D011506:Proteins; D014227:Triazines; C012842:Cibacron Blue F 3GA; D006493:Heparin