Catalytic properties of antibodies IgG in patients with multiple sclerosis

Abstract

Introduction: The research of multiple sclerosis (MS) pathogenesis is one of the most serious problems of modern medicine. MS is a clinically heterogeneous chronic demyelinating disease of the nervous system of unknown etiology. In MS, increased concentrations of IgG, which are found in the specific antibody (Ab) against the various components of myelin, antibodies to DNA, antibodies to other structures and tissues are present. Studies of the last decade have led to the discovery of the ability of antibodies to catalyze many different chemical reactions. Such antibodies possessing a catalytic activity have been termed abzymes. In patients with autoimmune diseases a high DNA hydrolyzing activity of AT has been revealed. Purpose: To study the DNA-ase and catalase activity of IgG, isolated from the blood plasma of patients with multiple sclerosis. Materials and Methods: Peripheral blood serum of patients with MS was used in the study. IgG was isolated by affinity chromatography on columns of Protein G-Sepharose. DNA-ase activity was determined by the degree of conversion of supercoiled form of pBluescript plasmid DNA into the ring, relaxed and linear forms. The reaction mixture volume of 15 ml contained: 20 mMtris-HCl, pH 7.5, 5 mM MgCl2, 10-20 mg / ml pBluescript DNA, and 0.1 - 0.2 mg / ml of antibody. After incubation for 2 hours at 35°C the reaction mixture was added 5 ml buffer solution of 4X, containing 1% SDS, 30% glycerol, 30 mM EDTA, 0.1% bromophenol blue. Electrophoresis was performed in 1.2% agarose gel. DNA in the gel was stained with ethidium bromide solution (0.5 mg / ml). Determination of catalase activity was performed spectrophotometrically (X = 240 nm.) On a spectrophotometer Specord. The reaction mixture consisted of 30 mM H20 2 solution at 50 mM phosphate buffer (pH = 7.0) of 1600 ml and 70 ml of a solution containing IgG in potassium phosphate buffer (pH 7.0). Results and conclusions: The study of the catalytic activity of IgG in multiple sclerosis patients revealed a high percentage of hydrolysis of DNA, reaching 100% in some patients. Hydrolysis of DNA Ig G, isolated from blood of healthy individuals does not exceed 1-2%. The ability of antibodies in multiple sclerosis patients to split hydrogen peroxide was first discovered. IgG, isolated from blood of healthy individuals did not have this ability. All studied antibodies were tested for homogeneity. The study of the catalytic properties of AT patients with multiple sclerosis will contribute to understanding the mechanism of pathogenesis of this disease.