PATHOGENETIC ROLE OF ABZYME-TYPE AUTOANTIBODIES IN THE ORGAN-SPECIFIC AUTOIMMUNE PATHOLOGY

Abstract

Abstract. The work deals with quantitative methods developed for estimation of nuclease and proteolytic activities of autoantibodies. By means of these techniques, appropriate catalytic activities of abzyme-type antibodies were studied in patients with diabetes mellitus type 1, and in subjects with autoimmune thyroiditis. Oppositely directed changes of the mentioned catalytic activities have been found for autoantibodies of different specificity. Autoantibodies occurring in autoimmune thyroiditis showed an increase of both nuclease and proteolytic activities. Meanwhile, the autoantibodies in diabetes mellitus had increased nuclease activity, along with decreased proteolytic activity. These findings are suggestive for existence of two pathogenetic mechanisms in organ-specific autoimmune pathology that are associated either with direct involvement of Fab fragments of auto-antibodies in autoimmune destruction, or with complement-dependent lysis mediated by Fc-fragments and cytotoxic destruction of target cells by cytotoxic T-lymphocytes. The unique site-specific catalytic autoantibodies were established to exert a selective destructive effect upon target cells, thus making a major contribution to the antibody-dependent mechanisms of cytotoxicity in autoimmune diseases. (Med. Immunol., 2011, vol. 13, N 2-3, pp 145-150)

Keywords

• autoimmune disorders
• diabetes mellitus
• autoimmune thyroiditis
• abzyme-type autoantibodies
• catalytic activity