Proteolytic activity of IgGs from blood serum of wistar rats at experimental rheumatoid arthritis

Yu. Ya. Kit

doi:10.15407/ubj86.05.095

Abstract

The aim of this work was to study the proteolytic activity of IgGs purified from blood serum of Wistar rats at experimental rheumatoid arthritis (ERA) induced by an injection of bovine collagen of type II. Twenty rats were immunized with a preparation of bovine collagen II (Sigma-Aldrich, USA) in the presence of complete Freund's adjuvant. ERA development was determined by inflammation in limbs of treated animals. IgG preparations were isolated from blood serum of immunized and non-immunized animals by precipitation of antibodies with 33% ammonium sulfate followed by chromatography on the Protein G-Sepharose column. Human histone H1, bovine collagen II, calf thymus histones, myelin basic protein (MBP), bovine serum albumin (BSA), and bovine casein were used as substrates of the proteolytic activity of IgGs. It was found that IgG preparations from blood serum of rats with ERA were capable of cleaving histone H1 and MBP, however, they were catalytically inactive towards collagen II, casein, BSA, and core histones. IgGs from blood serum of non-immunized rats were proteolytically inactive towards all used protein substrates. Thus, we demonstrated that immunization of rats with bovine collagen II induced IgG-antibodies possessing the proteolytic activity towards histone H1 and MBP. This activity might be associated with the development of inflammatory processes in the immunized rats.

Highlights

I nteraction of antibodies with antigens may cause binding, and a destruction or modification of these antigens
We have found for the first time that IgG-protabzymes capable of hydrolyzing histone Н1 are present in blood serum of patients with multiple sclerosis, systematic lupus erythematosus (SLE), multiple myeloma, as well as in colostrum of healthy women [11, 15, 16]
We suggested that the appearance of IgG-protabzymes in blood serum may be caused by an inflammatory process linked with development of the autoimmune diseases

Summary

Introduction

I nteraction of antibodies with antigens may cause binding, and a destruction or modification of these antigens. We have found for the first time that IgG-protabzymes capable of hydrolyzing histone Н1 are present in blood serum of patients with multiple sclerosis, systematic lupus erythematosus (SLE), multiple myeloma, as well as in colostrum of healthy women [11, 15, 16]. Comparative studies of blood serum of SLE patients and colostrum of healthy mothers have shown that IgG- and sIgA-protabzymes with affinity for histone H1 are capable of cleaving two different substrates – histone H1 and MBP [17, 18] Their level in blood serum positively correlated with heaviness of multiple sclerosis [19, 20]. We aimed at a search of proteolytically active IgG in blood serum of rats with experimental collagen-induced arthritis

Objectives

Methods

Results