IgG-Dependent Dismutation of Superoxide in Patients with Different Types of Multiple Sclerosis and Healthy Subjects

This work is the first to demonstrate that class G immunoglobulins (IgGs) in patients with multiple sclerosis and healthy individuals have the ability to catalyze the dismutation reaction of the superoxide anion radical. Thus, superoxide dismutase (SOD) activity is an intrinsic property of antibodies, which is confirmed by a number of stringent criteria. SOD activity of IgGs in patients with multiple sclerosis statistically significantly exceeds such activity in healthy individuals by 2-4 times. Moreover, the maximum activity has been registered in patients with relapsing remitting multiple sclerosis. The kinetic characteristics of the SOD reaction of IgGs are several orders of magnitude lower than those for the SOD enzyme but do not differ between patients with multiple sclerosis and healthy individuals. Consequently, abzymes with SOD activity have a lower catalysis rate than that of the enzymes and form a stronger complex with the substrates. Inhibitory analysis showed that this activity is inhibited by classical metal-dependent SOD inhibitors. The activity of IgGs was inhibited by classical metal-dependent inhibitors EDTA and TETA (triethylenetetramine). Also, high catalase activity of IgGs was detected in these patients. We suggest that these abzymes help protect the body from oxidative stress.