IgGs containing λ- and κ-type light chains and of all subclasses (IgG1-IgG4) from the sera of patients with autoimmune diseases and viral and bacterial infections hydrolyze DNA.

We present the first evidence demonstrating that small fractions of IgGs of all four subclasses (IgG1-IgG4) from patients with viral (tick-borne encephalitis), bacterial infections (streptococcal infection or erysipelas), and suppurative surgical infections caused by epidermal staphylococci as well as from patients with autoimmune diseases (systemic lupus erythematosus and multiple sclerosis) are catalytically active in the hydrolysis of supercoiled DNA. The hydrolysis of DNA was analyzed by agarose gel electrophoresis. The catalytic activities of nonfractionated IgGs increased in the following order: tick-borne encephalitis < suppurative surgical infection < streptococcal infection < multiple sclerosis < systemic lupus erythematosus, whereas IgGs of healthy donors were inactive. However, the pools of antibodies corresponding to any particular disease were characterized by a specific ratio of IgGs of all four subclasses (IgG1-IgG4) and IgGs containing λ- and κ-type light chains, and each of these subfractions of immunoglobulins demonstrated characteristic relative DNase activity. The relative activities of IgGs containing λ-type light chains may on average be higher, lower, or comparable with those for IgGs with κ-type light chains. The relative contributions of IgGs of different subclasses to the total activity of IgGs also varied widely in the case of various diseases: IgG1 (7%-45%), IgG2 (0.4%-73%), IgG3 (0%-12%), and IgG4 (9%-66%). Thus, immune systems of patients with different diseases can generate a variety of anti-DNA abzymes of different types and with different catalytic properties, which can play an important role in the pathogenesis or protection from the development of these diseases.

DNA-hydrolyzing activity of IgG antibodies from the sera of patients with tick-borne encephalitis.

DNase autoantibodies (Abzs) can be found in the blood of patients with several autoimmune diseases, while the blood of healthy donors or patients with diseases with an insignificant disturbance of the immune status does not contain DNase Abzs. Here we present the first analysis of the DNase Abzs activity in the patients with tick-borne encephalitis (TBE). Several strict criteria have been applied to show that the DNase activity is an intrinsic property of IgGs from the sera of TBE patients but not from healthy donors. The relative activity of IgGs has been shown to vary extensively from patient to patient, but most of the preparations (91%) had detectable levels of the DNase activity. Polyclonal DNase IgGs were not active in the presence of EDTA or after a dialysis against EDTA, but could be activated by several externally added metal ions, with the level of activity decreasing in the order Mn(2+) + Ca(2+) > or = Mn(2+)+ Mg(2+) > or = Mn(2+) > or = Mg(2+) + Ca(2+) > or = Co(2+) > or = Mg(2+) > Ca(2+), while K(+), Na(+), Ni(2+), Zn(2+), and Cu(2+) did not stimulate DNA hydrolysis. Affinity chromatography on DNA-cellulose separated the DNase IgGs into many subfractions with various affinities for DNA and very different levels of the relative activity. Possible reasons for catalytic diversity of polyclonal human Abzs are discussed.

DNA-hydrolysing activity of IgG antibodies from the sera of patients with diseases caused by different bacterial infections.

DNase autoantibodies (Abs) can be found in the blood of patients with several autoimmune diseases, while the blood of healthy donors or patients with diseases with insignificant disturbances of the immune status does not contain the DNase Abs. Here we have analysed for the first time the DNase activity in the patients with diseases caused by several bacterial infections. Several rigid criteria have been applied to show that the DNase activity is an intrinsic property of IgGs from the sera of patients with bacterial diseases but not from healthy donors. The relative activity of IgGs has been shown to vary extensively between the diseases analysed and from patient to patient, but most of the preparations had detectable levels of the DNase activity. On average, the catalytic activities were significantly lower than in patients with autoimmune pathologies and increased in the following order: streptococcal infection (erysipelas) < urogenital chlamydiosis associated with arthritis (Reiter's disease) < meningococcal meningitis < shigellosis < suppurative surgical infections caused by Staphylococcus aureus < suppurative surgical infections caused by epidermal staphylococci < urogenital ureaplasmosis associated with reactive arthritis. While intact IgGs possessed this catalytic activity, separated light chains of polyclonal Abs appeared to be even more active in the hydrolysis of DNA.