Dear Editor,
I enjoyed to read Newsletter of Medical Science Monitor Publication which is the August 2005 issue. Especially, I was interested in an article subscribed by Polosukhina DI et al entitled Hydrolysis of myelin basic protein by IgM and IgA antibodies from the sera of patients with multiple sclerosis [1]. They display the generation by the immune systems of individual multiple sclerosis (MS) patients of a variety of polyclonal IgGs, IgMs, and IgAs with different proteolytic properties, which hydrolyze myelin basic protein(MBP), the major protein component of the myelin-proteolipid shell of axons and a well-known MS autoantigen.
It is true that the catalytic activity of the Ig fractions was not due to contamination by enzyme as author described. Although this article proved the rigid criteria as the presence of catalytic activity activity only in the antibodies of patients with autoimmune dieseas and not in healthy donors, as electrophoretic homogeneity of IgMs and IgAs, as complete adsorption of the hMBP-hydrolyzing activity by anti-IgM and anti-IgA Sepharoses, as FPLC gel filtration of the IgMs and IgAs did not lead to a disappearance of the activity and so on, there is no evidence that the Fab fragment, prepared from IgM or IgA by papain treatment, retained the hydrolytic activity to hMBP which was proven by the first article concerning natural abzymes to the VIP-hydrolyzing activity from the sera of paients with asthma [2]. It is more reliable to be able to show that a monoclonal antibody and a Fab fraction of this monoclonal antibody to hMBP has a hMBP-hydrolyzing activity. It is reasonable that the destruction of myelin-proteolipid shell of axons may be due to this the hMBP-hydrolyzing activity by immunoglobulins in the MS patients. Why the autoantibody has only this hydrolyzing activity? Does the natural antibody to just conventional virus hydrolyze an antigen molecule of virus ? It should be analyzed this possibility using the specific monoclonal antibody (Fab fraction) to a virus. What kind of gene involve to this kind of activity ? Anyway, the catalytic natural antibody may be also an important role of natural immune response to prevent the infection as well as the catalytic auto-antibodies from patients with autoimmune disease.

Sincerely,
Shigemasa Sawada
Professor of Medicine, Division of Rheumatology
and Hematology, Nihon University Nerima Hikarigaoka Hospital, Tokyo, Japan,
e-mail: [email protected]

References:
1.Polosukhinaa DI, Buneva VN, Doronin BM et al: Hydrolysis of myelin basic protein by IgM and IgA antibodies from the sera of patients with multiple sclerosis. Med Sci Monit, 2005; 11(8): BR266–BR272
2.Paul S, volle DJ, Beach CM et al: Catalytic hydrolysis of vasoactive intestinal peptide by human autoantibody. Science, 1989; 244: 1158–61

Keywords: Catalysis, Chromatography, Gel, Hydrolysis, Immunoglobulin A - blood, Immunoglobulin M - blood, Multiple Sclerosis - blood, Myelin Basic Protein - blood