Catalytic diversity of polyclonal RNA-hydrolyzing IgG antibodies from the sera of patients with systemic lupus erythematosus

Autoantibody-Abzymes with Catalase Activity in Experimental Autoimmune Encephalomyelitis Mice

The exact mechanisms of the evolution of multiple sclerosis are still unknown. At the same time, the development in C57BL/6 mice of experimental autoimmune encephalomyelitis (EAE, simulating human multiple sclerosis) happens as a result of the violation of bone marrow hematopoietic stem cell differentiation profiles integrated with the production of toxic auto-antibodies splitting the basic myelin protein, myelin oligodendrocyte glycoprotein (MOG), histones, and DNA. It has been shown that IgGs from the plasma of healthy humans and autoimmune patients oxidize many different compounds due to their peroxidase (H2O2-dependent) and oxidoreductase (H2O2-independent) activities. Here, we first analyzed the changes in the relative catalase activity of IgGs from C57BL/6 mice blood plasma over time at different stages of the EAE development (onset, acute, and remission phases). It was shown that the catalase activity of IgGs of 3-month-old mice is, on average, relatively low (kcat = 40.7 min-1), but it increases during 60 days of spontaneous development of EAE 57.4-fold (kcat = 2.3 × 103 min-1). The catalase activity of antibodies increases by a factor of 57.4 by 20 days after the immunization of mice with MOG (kcat = 2.3 × 103 min-1), corresponding to the acute phase of EAE development, and 52.7-fold by 60 days after the treatment of mice with a DNA-histone complex (kcat = 2.1 × 103 min-1). It is the acceleration of the EAE development after the treatment of mice with MOG that leads to the increased production of lymphocytes synthesizing antibodies with catalase activity. All data show that the IgGs' catalase activity can play an essential role in reducing the H2O2 concentration and protecting mice from oxidative stress.

Catalytic Antibodies: Design, Expression, and Their Applications in Medicine

Catalytic antibodies made it feasible to develop new catalysts, which had previously been the subject of research. Scientists have discovered natural antibodies that can hydrolyze substrates such as nucleic acids, proteins, and polysaccharides during decades of research, as well as several ways of producing antibodies with specialized characteristics and catalytic functions. These antibodies are widely used in chemistry, biology, and medicine. Catalytic antibodies can continue to play a role and even fully prevent the emergence of autoimmune disorders, especially in the field of infection and immunity, where the process of its occurrence and development often takes a long time. In this work, the development, design and evolution methodologies, and the expression systems and applications of catalytic antibodies, are discussed. Trial registration: not applicable.

Multiple Sclerosis: Enzymatic Cross Site-Specific Recognition and Hydrolysis of H3 Histone by IgGs against H3, H1, H2A, H2B, H4 Histones, Myelin Basic Protein, and DNA

Histones have a specific key role in the remodeling of chromatin and gene transcription. In the blood, free histones are damage-connected proteins. Myelin basic protein (MBP) is the major component of the myelin-proteolipid sheath of axons. Antibodies possessing enzymatic activities (abzymes, ABZs) are the specific features of several autoimmune pathologies. IgGs against five histones, MBP, and DNA were obtained from the sera of multiple sclerosis (MS) patients using several affinity chromatographies. The sites of H3 histone splitting by Abs against five individual histones, MBP, and DNA were revealed by MALDI mass spectrometry. It was shown that the number of H3 splitting sites by IgGs against five various histones is different (number of sites): H3 (11), H1 (14), H2A (11), H4 (17), MBP (22), and DNA (29). IgGs against five different histones hydrolyze H3 at different sites, and only a few them coincide. The main reason for the enzymatic cross-reactivity of Abs against H3 and four other histones, as well as MBP, might be the high level of these proteins’ homology. The effective hydrolysis of the H3 histone at 29 sites with IgGs against DNA can be explained by the formation of chimeric abzymes against hybrid antigenic determinants formed by different histones and MBP at the junction of these protein sequences with DNA. The active centers of such abzymes contain structural elements of canonical DNases and proteases. Since free histones are pernicious proteins, antibodies–ABZs against five histones, MBP, and DNA could have a negative role in the pathogenesis of MS and probably other various autoimmune diseases.

MicroRNAs of Milk in Cells, Plasma, and Lipid Fractions of Human Milk, and Abzymes Catalyzing Their Hydrolysis

Human milk provides neonates with various components that ensure newborns’ growth, including protection from bacterial and viral infections. In neonates, the biological functions of many breast milk components can be very different compared with their functions in the body fluids of healthy adults. Catalytic antibodies (abzymes) that hydrolyze peptides, proteins, DNAs, RNAs, and oligosaccharides were detected, not only in the blood sera of autoimmune patients, but also in human milk. Non-coding microRNAs (18−25 nucleotides) are intra- and extracellular molecules of different human fluids. MiRNAs possess many different biological functions, including the regulation of several hundred genes. Five of them, miR-148a-3p, miR-200c-3p, miR-378a-3p, miR-146b-5p, and let-7f-5p, were previously found in milk in high concentrations. Here, we determined relative numbers of miRNA copies in 1 mg of analyzed cells, lipid fractions, and plasmas of human milk samples. The relative amount of microRNA decreases in the following order: cells ≈ lipid fraction > plasma. IgGs and sIgAs were isolated from milk plasma, and their activities in the hydrolysis of five microRNAs was compared. In general, sIgAs demonstrated higher miRNA-hydrolyzing activities than IgGs antibodies. The hydrolysis of five microRNAs by sIgAs and IgGs was site-specific. The relative activity of each microRNA hydrolysis was very dependent on the milk preparation. The correlation coefficients between the contents of five RNAs in milk plasma, and the relative activities of sIgAs compared to IgGs in hydrolyses, strongly depended on individual microRNA, and changed from −0.01 to 0.80. Thus, it was shown that milk contains specific antibodies (abzymes) that hydrolyze microRNAs specific for human milk.

Multiple Sclerosis: Enzymatic Cross Site-Specific Recognition and Hydrolysis of H2A Histone by IgGs against H2A, H1, H2B, H3 Histones, Myelin Basic Protein, and DNA

Histones have a paramount role in chromatin remodeling and gene transcription. Free histones are damage-associated molecules in the blood; administration of histones to animals drives systemic inflammatory and toxic effects. Myelin basic protein (MBP) is the most crucial component of the axon myelin-proteolipid sheath. Antibodies-abzymes with different enzymatic activities are very toxic and an essential feature of some autoimmune diseases. Electrophoretically homogeneous IgGs against H1, H2A, H2B, H3, H4, MBP, and DNA were derived from sera of multiple sclerosis (MS) patients by several affinity chromatographies. Using MALDI-TOFF mass spectrometry, it was shown that IgGs against H2A split H2A at 12 sites; the number of H2A hydrolysis sites by antibodies against other antigens is different: H1 (19), H2B (11), H3 (15), H4 (9), MBP (10), and DNA (23), and they only partly match. Thus, the complex formation polyreactivity and the enzymatic cross-activity of pernicious humans IgGs against five histones, MBP, and DNA have been shown for the first time. The data obtained indicate that the formation of such polyspecific-polyreactive abzymes, whose single active center can recognize and hydrolyze different substrates, can occur due to the formation of antibodies against hybrid antigenic determinants consisting of several histone protein sequences. IgGs with high affinity for DNA with DNase and protease activities may be antibodies against DNA-histone complex antigenic determinants, including protein and DNA sequences. Polyreactive IgGs-abzymes against MBP, five histones, and DNA with extended cytotoxicity can play a very negative role in the pathogenesis of multiple sclerosis and probably other different diseases.

Maximally Expressed miRNAs of Milk in Cells, Plasma and Lipid Fraction of Human Milk and Antibodies-Abzymes Catalyzing Their Hydrolysis

As shown in many studies, one of the earliest statistically significant indicators of the development of many autoimmune diseases (ADs) is the appearance in the blood of antibodies with catalytic activities (abzymes) hydrolyzing different autoantigens. Antibodies-abzymes having different enzymatic activities are a specific and essential feature of some ADs. Most abzymes are harmful to humans. Free histones in the blood are damage-associated proteins, and their administration to animals drives systemic inflammatory and toxic effects. Myelin basic protein (MBP) is the most critical component of the axon myelin-proteolipid sheath. Hydrolysis of MBP by abzymes leads to the disruption of nerve impulses. Here, we analyzed the possible pathways for the formation of unusual antibodies and abzymes that exhibit polyspecificity in recognition during complex formation with partially related antigens and possess the ability to catalyze several different reactions for the first time. Using IgGs of HIV-infected and multiple sclerosis patients against five individual histones (H1–H4), MBP, and DNA, it was first shown that abzymes against each of these antigens effectively recognize and hydrolyze all three antigens: histones, MBP, and DNA. The data obtained indicate that the formation of such polyspecific abzymes, whose single active center can recognize different substrates and catalyze several reactions, can occur in two main ways. They can be antibodies against DNA–protein complex hybrid antigenic determinants containing proteins and nucleic sequences. Their formation may also be associated with the previously described phenomenon of IgG extensive LH half-molecule (containing one L-light and one H-heavy chains) exchange leading to H₂L₂ molecules containing HL halves with variable fragments recognizing different antigens.

Secretory immunoglobulin A from human milk hydrolyzes 5 histones and myelin basic protein

Mother's milk provides newborns with various nutrients (e.g., enzymes, proteins, peptides, hormones, antibodies) that help babies grow and protect them from bacterial and viral infections. The functions of many components of breast milk can be very different from their corresponding functions in body fluids of healthy adults. Catalytic antibodies (abzymes) that hydrolyze peptides, proteins, DNA, RNA, and oligosaccharides were detected not only in human milk, but also in the blood sera of autoimmune patients. However, abzymes with unexpected synthetic activities (lipids, oligosaccharides, and protein kinase activities) were revealed in milk that were not found in the blood of autoimmune patients. The nutrition of infants with fresh milk has a very specific role; newborns are well protected by antibodies of mother's milk (passive immunity). Protease abzymes were found in the blood sera of autoimmune patients, whereas healthy humans usually do not contain such autoantibodies. Here, we present the first evidence that the milk of healthy mothers contains secretory (s)IgA that effectively hydrolyze 5 histones (e.g., H1, H2A, H2B, H3, and H4) and myelin basic protein (MBP). Several rigid criteria were applied to show that protease activity is an intrinsic property of sIgA. Milk abzymes against 5 histones cannot hydrolyze different control proteins except histones and MBP, whereas autoantibodies against MBP split this protein and 5 histones. Antibodies against histones and MBP exhibit complexation polyreactivity as well as specific and unusual catalytic cross-reactivity. With some exceptions, the specific sites of hydrolysis of H1, H2A, and H2B by sIgA against histones do not coincide with the sites of hydrolysis by abzymes against MBP. On the whole, fresh human milk is a very specific source of many of the most unusual antibodies and abzymes.

Multiple Sclerosis: Enzymatic Cross Site-Specific Hydrolysis of H1 Histone by IgGs against H1, H2A, H2B, H3, H4 Histones, and Myelin Basic Protein

Histones play a key role in chromatin remodeling and gene transcription. Further, free histones in the blood act as damage-associated molecules. Administration of histones to animals results in systemic inflammatory and toxic effects. Myelin basic protein is the principal constituent element of the myelin-proteolipid sheath of axons. Abzymes (antibodies with catalytic activities) are the original features of some autoimmune diseases. In this study, electrophoretically homogeneous IgGs against H1, H2A, H2B, H3, and H4 histones and myelin basic protein (MBP) were isolated from the blood sera of multiple sclerosis (MS) patients by several affinity chromatographies. Using MALDI mass spectrometry, the sites of H1 histone cleavage by IgGs against H1, H2A, H2B, H3, H4, and MBP were determined. It was shown that IgGs against H1 split H1 at 12 sites, while the number of cleavage sites by abzymes against other histones was lower: H2A (9), H2B (7), H3 (3), and H4 (3). The minimum rate of H1 hydrolysis was observed for antibodies against H3 and H4. A high rate of hydrolysis and the maximum number of H1 hydrolysis sites (17) were found for antibodies against MBP. Only a few sites of H1 hydrolysis by anti-H1 antibodies coincided with those for IgGs against H2A, H2B, H3, H4, and MBP. Thus, the polyreactivity of complexation and the enzymatic cross-activity of antibodies against H1, four other histones, and MBP have first been shown. Since histones act as damage molecules, abzymes against histones and MBP can play a negative role in the pathogenesis of MS and probably other different diseases as well.

Six catalytic activities and cytotoxicity of immunoglobulin G and secretory immunoglobulin A from human milk

In the milk of healthy women, antibodies were found with different catalytic activities (abzymes), which are absent in the sera of other healthy people. Moreover, it was previously shown that DNase antibodies-abzymes of patients with autoimmune diseases are cytotoxic to cancer cells. In this work, it was first shown that IgG and secretory IgA (sIgA) do not possess embryotoxicity; they practically do not affect the development of fertilized eggs of sea urchins but demonstrate sperm toxicity. After addition to the eggs of sperm preincubated with IgG and sIgA, the number of unfertilized eggs was increased, in the case of sIgA 1.6-fold higher than that for IgG. The suppression of the growth of MCF-7 breast cancer cells by sIgA was 2.2 times more effective than with IgG antibodies. The relative enzymatic activity of milk sIgA was higher than IgG (-fold): 1.9 (DNase), 4.6 (amylase), 1.7 (peroxidase), 1.3 (protease), 3.7 [hydrolysis of poly(C)], 3.3 [hydrolysis of poly(U)], and 1.7 (oxidation of 3,3'-diaminobenzidine). One of the possible reasons for the observed difference between sIgA and IgG could be that all 6 catalytic activities of sIgA were, on average, 2.6 times higher than that for IgG. Correlation coefficients between all the relative 6 enzymatic activities of IgG and sIgA and their toxicity to sea urchin sperm and to cancer cells were calculated. Maximum correlation coefficients were observed for DNase (+0.71), protease (+0.64) activities for sIgA, as well as protease (+0.59) and RNase (+0.77) of IgG with their toxicity toward sperm. The correlation coefficients were also high between peroxidase activity (+0.85) of sIgA and poly(U) hydrolysis by IgG (+0.58) with their suppression of tumor cell growth. It has been suggested that the catalytic activities of abzymes may be important in the manifestation of their sperm toxicity and inhibition of cancer cell growth.

IgGs-Abzymes from the Sera of Patients with Multiple Sclerosis Recognize and Hydrolyze miRNAs

Autoantibodies-abzymes hydrolyzing DNA, myelin basic protein, and oligosaccharides have been revealed in the sera of patients with multiple sclerosis (MS). In MS, specific microRNAs are found in blood and cerebrospinal fluid, which are characterized by increased expression. Autoantibodies, specifically hydrolyzing four different miRNAs, were first detected in the blood of schizophrenia patients. Here, we present the first evidence that 23 IgG antibodies of MS patients effectively recognize and hydrolyze four neuroregulatory miRNAs (miR-137, miR-9-5p, miR-219-2-3p, and miR-219-5p) and four immunoregulatory miRNAs (miR-21-3p, miR-146a-3p, miR-155-5p, and miR-326). Several known criteria were checked to show that the recognition and hydrolysis of miRNAs is an intrinsic property of MS IgGs. The hydrolysis of all miRNAs is mostly site-specific. The major and moderate sites of the hydrolysis of each miRNA for most of the IgG preparations coincided; however, some of them showed other specific sites of splitting. Several individual IgGs hydrolyzed some miRNAs almost nonspecifically at nearly all internucleoside bonds or demonstrated a combination of site-specific and nonspecific splitting. Maximum average relative activity (RA) was observed in the hydrolysis of miR-155-5p for IgGs of patients of two types of MS-clinically isolated syndrome and relapsing-remitting MS-but was also high for patients with primary progressive and secondary progressive MS. Differences between RAs of IgGs of four groups of MS patients and healthy donors were statistically significant (p < 0.015). There was a tendency of decreasing efficiency of hydrolysis of all eight miRNAs during remission compared with the exacerbation of the disease.

The association between EAE development in mice and the production of autoantibodies and abzymes after immunization of mice with different antigens

We have previously shown that immunization of C57BL/6 mice, prone to spontaneous development of experimental autoimmune encephalomyelitis (EAE), with three antigens (MOG_35-55 , DNA-histone complex or DNA-methylated BSA complex), alters the differentiation profiles of bone marrow haematopoietic stem cells (HSCs). These are associated with the production of autoantibodies (auto-Abs) against these antigens and the formation of abzymes hydrolysing DNA, MOG, myelin basic protein (MBP) and histones. Immunization of mice with antigens accelerates the development of EAE. This work is the first to analyse the ratio of auto-Abs without and with catalytic activities at different stages of EAE development (onset, acute and remission phases) after immunization of mice with the three specific antigens. Prior to immunization and during spontaneous in-time development of EAE, the concentration of auto-Abs against MBP, MOG, histones and DNA and activities of IgG antibodies in the hydrolysis of substrates increased in parallel; correlation coefficients = +0.69-0.94. After immunization with MOG, DNA-histone complex or DNA-met-BSA complex, both positive (from +0.13 to +0.98) and negative correlations (from -0.09 to -0.69) were found between these values. Our study is the first showing that depending on the antigen, the relative amount of harmful auto-Abs without and abzymes with low or high catalytic activities may be produced only at onset and in acute or remission phases of EAE. The antigen governs the EAE development rate, whereby the ratio of auto-Abs without catalytic activity and with enzymatic activities of harmful abzymes hydrolysing MBP, MOG, histones and DNA varies strongly between different disease phases.

Catalytic antibodies in the bone marrow and other organs of Th mice during spontaneous development of experimental autoimmune encephalomyelitis associated with cell differentiation

Exact mechanisms of autoimmune disease development are still yet unknown. However, it is known that the development of autoimmune diseases is associated with defects in the immune system, namely, the violation of the bone marrow hematopoietic stem cells (HSCs) differentiation profiles. Different characteristics of autoimmune reaction development in experimental autoimmune encephalomyelitis (EAE) prone Th mice characterizing T-lymphocytes response were analyzed using standard approaches. Profiles of several HSCs differentiation of bone marrow (BFU-E, CFU-E, CFU-GM, CFU-GEMM, T- and B-lymphocytes) of Th male and female mice during spontaneous development of EAE were noticeably different. Patterns of total lymphocytes, B- and T-cells proliferation in several different organs (bone marrow, blood, spleen, thymus, and lymph nodes) were also remarkably different. In addition, there were in time noticeable differences in their changes for some organs of male and female mice. Characters of changes in the profiles of CD4 and CD8 cells proliferation in some organs not always coincide with those for total T lymphocytes. The changes in the differentiation profiles of HSCs and the level of lymphocytes proliferation in the bone marrow and other organs were associated with the increase in the concentration of antibodies against DNA, myelin basic protein, and myelin oligodendrocyte glycoprotein, and catalytic antibodies hydrolyzing these substrates. Despite some differences in changes in the analyzed parameters, in general, the spontaneous development of EAE in male and female mice occurs to some extent in a comparable way.

IgGs-Abzymes from the Sera of Patients with Systemic Lupus Erythematosus Hydrolyzed miRNAs

Background and Objectives

Systemic lupus erythematosus (SLE) is an inflammatory disease. The sera of SLE patients contain antibodies-abzymes hydrolyzing myelin basic protein (MBP), DNA, nucleotides, and oligosaccharides. The blood of SLE patients contains an increased amount of some specific miRNAs. This study aimed to analyze a possible hydrolysis of eight microRNAs found in the blood of SLE patients with high frequency by blood antibodies-abzymes.

Patients and Methods

Using affinity chromatography of the serum proteins of SLE patients and healthy donors on protein G-Sepharose and following FPLC gel filtration, electrophoretically homogeneous IgG preparations containing no impurities of canonical RNases were obtained. These preparations were used to analyze their activity in the hydrolysis of eight miRNAs.

Results

It was shown that SLE IgGs hydrolyze very efficiently four neuroregulatory miRNAs (miR-219-2-3p, miR-137, miR-219a-5p, and miR-9-5p) and four immunoregulatory miRNAs (miR-326, miR-21-3p, miR-155-5p, and miR-146a-3p). To demonstrate that the miRNAs hydrolysis is an intrinsic property of SLE IgGs, several rigid criteria were checked. Only some IgGs of healthy donors showed very weak, but reliably detectable activity in the hydrolysis miRNAs. The average activity of SLE patients IgGs according to median values is statistically significant 84.8-fold higher than that of healthy donors. The maximum and comparable average activity (RA) was observed in the hydrolysis of three miRAs: miR-9-5p, miR-155-5p, and miR-326. MiR-9-5p plays an important role in the development of lupus nephritis, while miR-326 activates the production of antibodies by B cells. The major and moderate specific sites of the hydrolysis of each miRNA were revealed. The hydrolysis of eight microRNAs was mostly site specific. Several SLE IgGs hydrolyzed some miRNAs demonstrating a combination of site-specific and non-specific splitting.

Conclusion

Since inflammatory processes in SLE are associated with the change in miRNAs expression, the decrease in their concentration due to hydrolysis by autoantibodies-abzymes may be important for SLE pathogenesis.

Immunoglobulins with Non-Canonical Functions in Inflammatory and Autoimmune Disease States

Immunoglobulins are known to combine various effector mechanisms of the adaptive and the innate immune system. Classical immunoglobulin functions are associated with antigen recognition and the initiation of innate immune responses. However, in addition to classical functions, antibodies exhibit a variety of non-canonical functions related to the destruction of various pathogens due to catalytic activity and cofactor effects, the action of antibodies as agonists/antagonists of various receptors, the control of bacterial diversity of the intestine, etc. Canonical and non-canonical functions reflect the extreme human antibody repertoire and the variety of antibody types generated in the organism: antigen-specific, natural, polyreactive, broadly neutralizing, homophilic, bispecific and catalytic. The therapeutic effects of intravenous immunoglobulins (IVIg) are associated with both the canonical and non-canonical functions of antibodies. In this review, catalytic antibodies will be considered in more detail, since their formation is associated with inflammatory and autoimmune diseases. We will systematically summarize the diversity of catalytic antibodies in normal and pathological conditions. Translational perspectives of knowledge about natural antibodies for IVIg therapy will be also discussed.

IgGs from Human Milk Hydrolyze microRNAs

Mother’s milk provides breast-fed infants with various nutrients, including peptides, proteins, DNA, RNA, antibodies, and other bioactive components promoting neonatal growth and protecting infants from viral and bacterial infection. The functions of many human milk components regarding the nutrition and protection of newborns may be very different compared to those of various biological fluids of healthy adults. For example, human milk contains catalytic antibodies (abzymes) with protein, lipid, and oligosaccharide kinase activities, which are absent in the biological fluids of healthy people and autoimmune patients. Obviously, the nutrition of infants with fresh breast milk is a special phenomenon having a very specific and important role. Here, we have shown that mother’s milk IgGs effectively split homo-(pN)23, and four miRNAs: miR-137, miR-219a-5p, miR-219-2-3p, and miR-9-5p. It was shown that ribonuclease activity is a unique property of milk IgGs. On average, individual IgGs hydrolyze (pA)23, (pU)23, and (pC)23 nonspecifically and with comparable efficiency, whereas the hydrolysis of four miRNAs is predominately site-specific. The specific sites of the hydrolysis of four miRNAs by IgGs from the blood of schizophrenic (SCZ) patients and secretory immunoglobulins A (sIgAs) from human milk were found earlier. The sites of the hydrolysis of four miRNAs by milk IgGs and sIgA-abzymes are almost the same, but are significantly different in comparison with those for SCZ IgGs. In addition, in contrast to the SCZ IgGs, milk IgGs and sIgAs efficiently hydrolyzed miRNAs in the duplex regions formed by their terminal sequences.

Extreme Diversity of IgGs Against Histones, DNA, and Myelin Basic Protein in the Cerebrospinal Fluid and Blood of Patients with Multiple Sclerosis

It was recently shown that IgGs from sera of multiple sclerosis (MS) patients are active in the hydrolysis of DNA and myelin basic protein (MBP). We first analyzed the relative concentration of antibodies against five histones (H1, H2a, H2b, H3, and H4) in the cerebrospinal fluid (CSF) and serum of patients with MS. The relative concentrations of blood and CSF IgGs against histones and their activity in the hydrolysis of five histones varied greatly from patient to patient. However, all 28 IgG preparations were hydrolyzed from one to five histones. Relative activities and correlation coefficients among the activities of IgGs from serum and CSF in the hydrolysis of five histones (H1, H2a, H2b, H3, and H4), DNA, and MBP were calculated. It was shown that auto-IgGs from CSF and sera of MS patients are extremely heterogeneous in their affinity to histones, MBP, and DNA. The heterogeneity of IgG-abzymes hydrolyzing DNA, MBP, and histones from CSF and sera was also demonstrated using their isoelectrofocusing. The isofocusing profiles DNase, MBP-, and histone-hydrolyzing activities of IgGs may be very different for various individuals, but the total IgG subfractions with all their activities are distributed from pH 3 to 10.

Production of Abzymes in Th, CBA, and C57BL/6 Mice before and after MOG Treatment: Comparing Changes in Cell Differentiation and Proliferation

Till yet there is no data concerning mechanisms of autoimmune diseases development. Experimental autoimmune encephalomyelitis (EAE) prone C57BL/6 (T- and B-lymphocyte response), non-autoimmune CBA, and Th mice with T cell response were immunized with myelin oligodendrocyte glycoprotein (MOG35-55) to compare different characteristics of autoimmune reaction development. Bone marrow differentiation profiles of hematopoietic stem cells (HSCs), lymphocyte proliferation in various organs associated with the production of antibodies against DNA, myelin basic protein (MBP), and MOG, as well as abzymes hydrolyzing these antigens, were analyzed before and after immunization. Profiles of HSC differentiation [BFU-E (erythroid burst-forming unit (early erythroid colonies), CFU-E (erythroid burst-forming unit (late erythroid colonies), CFU-GM (granulocytic-macrophagic colony-forming unit), and CFU-GEMM granulocytic-erythroid-megakaryocytic-macrophagic colony-forming unit] and patterns of lymphocyte proliferation in different organs (brain, spleen, thymus, and lymph nodes) were very different for C57BL/6, CBA, and Th mice. We conclude that only C57BL/6 mice were predisposed to spontaneous and MOG-induced acceleration of EAE development. CBA mice are not prone to the development of autoimmune reactions. After immunization, Th mice demonstrate changes in several parameters similar to C57BL/6 and other to CBA mice; Th mice are more prone to developing autoimmune reactions than CBA mice. Our data may be important for understanding the combined presence in mice lymphocytes with T and B cell responses for spontaneous and induced autoimmune diseases.

Systemic lupus erythematosus: Possible localization of trypsin-like and metalloprotease active centers in the protein sequence of the monoclonal light chain (NGTA2-Me-pro-Tr)

It was previously shown that several monoclonal light chains corresponding to the phagemid library of recombinant peripheral blood lymphocyte immunoglobulin light chains of patients with systemic lupus erythematosus specifically hydrolyze only myelin basic protein (MBP). Canonical enzymes usually have only one active site catalyzing some kind of chemical reaction. It was shown previously that in contrast to classical enzymes, preparations of one of the light chains (NGTA2-Me-pro-Tr) showed two optimal pH values, two optimal concentrations of metal ions, and two K_m values for MBP. One protease active site of NGTA2-Me-pro-Tr was trypsin like, whereas second one was metal dependent. In this article, a search for protein sequences of NGTA2-Me-pro-Tr responsible for catalytic functions was carried out. We performed, for the first time, analysis of the homology of the protein sequence of NGTA2-Me-pro-Tr with those of several classical Zn²⁺ - and Ca²⁺ -dependent, as well as human serine, proteases. The analysis allowed us to identify the protein sequences of NGTA2-Me-pro-Tr responsible for serine-like activity, the binding of MBP, and chelation of metal ions and catalysis directly. The data obtained are summarized using hypothetical models of the structure of the two active centers of a very unusual light chain of antibodies (Abs). The findings obtained may be very important for understanding possible structure of active centers of very unusual light chain of Abs possessing several enzymatic activities.

Changes in cell differentiation and proliferation lead to production of abzymes in EAE mice treated with DNA-Histone complexes

Experimental autoimmune encephalomyelitis (EAE)-prone C57BL/6 mice are used as a model of human multiple sclerosis. We immunize mice with myelin oligodendrocyte glycoprotein (MOG), DNA-histone and DNA-methylated bovine serum albumin (met-BSA) complexes to reveal different characteristics of EAE development including bone marrow lymphocyte proliferation and differentiation profiles of hematopoietic stem cells. Immunization of C57BL/6 mice with MOG35-55 results in the acceleration of EAE development. Anti-DNA antibodies are usually directed against DNA-histone complexes resulting from cell apoptosis. During the acute EAE phase (7-20 days after immunization), catalytic antibodies efficiently hydrolysing myelin basic protein (MBP), MOG and DNA are produced with parallel suppression of antibodies hydrolysing histones. We could show that in contrast to MOG, immunization with histone-DNA results in a reduction of proteinuria, a significant increase in anti-DNA, anti-MBP and anti-MOG antibody titres, as well as an increase in their catalytic activities for antigen hydrolysis, but slightly changes the concentration of cytokines. Contrary to MOG, DNA-histone and DNA-met-BSA only stimulated the formation of anti-DNA antibodies hydrolysing DNA with a long delay (15-20 days after immunization). Our data indicate that for C57BL/6 mice immunization with DNA-met-BSA and DNA-histone complexes may have opposing effects compared to MOG. DNA-histone stimulates the appearance of histone-hydrolysing abzymes in the acute EAE phase, while abzymes with DNase activity appear at significantly later time-points. We conclude that MOG, DNA-histone and DNA-met-BSA have different effects on numerous bone marrow, cellular, immunological and biochemical parameters of immunized mice, but all antigens finally significantly stimulate the development of the EAE.

Catalytic antibodies in patients with systemic lupus erythematosus

OBJECTIVE

Antibodies with catalytic (hydrolytic) properties to DNA or RNA have been reported in systemic lupus erythematosus (SLE). However, it is well known that ethnicity plays an important role in the presentation of SLE and severity of the disease; hence, these data may not truly represent a general feature of all SLE patients. Therefore, we have analyzed the hydrolyzing activity of immunoglobulin G (IgG) of SLE patients from the Indian population with an aim to decode whether the catalytic antibody response represents part of an active disease process.

METHODS

IgGs were isolated from the sera of 72 consecutive patients diagnosed with SLE. As a control, IgGs from healthy donors were used. The catalytic activity of IgG was measured by PFR-MCA and affinity-linked oligonucleotide nuclease assay.

RESULTS

IgGs from patients with SLE from the Indian subcontinent displayed significantly higher hydrolysis rates of both the surrogate substrate, PFR-MCA, and the DNA than IgG from healthy individuals. Intergroup comparisons of the IgG-PFR-MCA interactions with clinical manifestations of the disease demonstrated a significantly increased level of hydrolysis among the patients with renal involvement who tested positive for anti-dsDNA antibodies. The PFR-MCA hydrolysis also appears to be associated with the active disease (p=0.0988, vs. inactive group).

CONCLUSION

The prevalence of catalytic antibodies represents a general feature of SLE patients, irrespective of their origin.

The DNA-hydrolyzing activity of IgG antibodies from human placenta

OBJECTIVE

Since during pregnancy and lactation women tend to develop autoimmune processes, characterization of placenta immunoglobulins and their possible catalytic functions is a very important step towards understanding the function of placenta.

METHODS

ELISA, affinity chromatography, SDS-PAGE and MALDI mass spectrometry were used.

RESULTS

It was shown, that ten placentas contain in average 1.1 ± 0.33 mg IgGs/g of placenta and 0.11 ± 0.1 mЕ anti-DNA antibodies/g of placenta. All ten individual IgG preparations were characterized by a specific ratio and various combinations of heavy (47.5-51.7 kDa) and light (22.2-33.3 kDa) chains with different molecular masses. All intact IgGs demonstrate DNase but have not amylase activity. Several strict criteria have been used to show that the DNase activity is an intrinsic property of placenta IgGs. The heavy chains of antibodies were catalytically inactive. The light chains of 22-24 kDa of all IgGs demonstrated maximal DNase activity, while the chains of approximately 25-33.2 kDa were significantly less active. IgGs were completely inactive after dialysis against EDTA. The optimal external cofactors of placenta DNase abzymes are Mg²⁺ and Cu²⁺ ions, while, activity in the presence of Mn²⁺ and Ca²⁺ is approximately 3-4-fold lower. Activation of DNase abzymes by Cu²⁺ ions was revealed for the first time. Placental antibodies possess selective cytotoxicity against cancer cells.

CONCLUSION

It was shown previously, that appearance of serum DNase abzymes is the good indicator of the beginning and obvious spontaneous or induced autoimmune diseases. The detection of placenta DNase antibodies indicates that during pregnancy, autoimmune processes can affect this organ.

Blood-Derived RNA- and microRNA-Hydrolyzing IgG Antibodies in Schizophrenia Patients

Abzymes with various catalytic activities are the earliest statistically significant markers of existing and developing autoimmune diseases (AIDs). Currently, schizophrenia (SCZD) is not considered to be a typical AID. It was demonstrated recently that antibodies from SCZD patients efficiently hydrolyze DNA and myelin basic protein. Here, we showed for the first time that autoantibodies from 35 SCZD patients efficiently hydrolyze RNA (cCMP > poly(C) > poly(A) > yeast RNA) and analyzed site-specific hydrolysis of microRNAs involved in the regulation of several genes in SCZD (miR-137, miR-9-5p, miR-219-2-3p, and miR-219a-5p). All four microRNAs were cleaved by IgG preparations (n = 21) from SCZD patients in a site-specific manner. The RNase activity of the abzymes correlated with SCZD clinical parameters. The data obtained showed that SCZD patients might display signs of typical autoimmune processes associated with impaired functioning of microRNAs resulting from their hydrolysis by the abzymes.

Hydrolysis by catalytic IgGs of microRNA specific for patients with schizophrenia

Significant importance of autoimmune changes in the pathogenesis of schizophrenia (SCZ) is not established. Here, we present the first evidence that autoantibodies of 100% SCZ patients possess RNase activity: сCMP > poly(C) > poly(A) > yeast RNA. In addition, we have got an unexpected result: there was revealed site-specific hydrolysis of four known SCZ specific microRNAs (miR-137, miR-9-5p, miR-219-2-3p, and miR-219a-5p) playing an important role in the regulation of several genes functioning. Three major of cleavage sites are located in the microRNA loops or duplex parts directly articulated with the loops. RNase abzymes can contribute to decreasing of microRNAs effects on the functioning of numerous genes and the products of their transcription. Therefore, abzymes with RNase activity may be to some extent important for the development of schizophrenia. © 2018 IUBMB Life, 70(2):153-164, 2018.

Catalase activity of IgG antibodies from the sera of healthy donors and patients with schizophrenia

We present first evidence showing that some electrophoretically homogeneous IgGs from the sera of patients with schizophrenia (36.4%) and their Fab and F(ab)2 fragments as well as from healthy donors (33.3%) possess catalase activity. The relative catalase activity of IgGs from the sera of individual schizophrenia patients (and healthy donors) significantly varied from patient to patient, but the activity of IgGs from healthy donors is on average 15.8-fold lower than that for schizophrenia patients. After extensive dialysis of purified IgGs against EDTA chelating metal ions, the relative catalase activity of IgGs decreases on average approximately 2.5-3.7-fold; all IgGs possess metal-dependent and independent catalase activity. The addition of external Me2+ ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. The best activator of dialyzed and non-dialyzed IgGs is Co2+, the activation by Cu2+, Mn2+, and Ni2+ ions were rare and always lower than by Co2+. Every IgG preparation demonstrates several individual sets of very well expressed pH optima in the pH range from 4.0 to 9.5. These data speak for the individual repertoire of catalase IgGs in every person and an extreme diversity of abzymes in their pH optima and activation by different metal ions. It is known that antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases represent critical defense mechanisms preventing oxidative modifications of DNA, proteins, and lipids. Catalase activity of human IgGs could probably also play a major role in the protection of organisms from oxidative stress and toxic compounds.

How human IgGs against DNA recognize oligonucleotides and DNA

In the literature, there are no available data on how anti-DNA antibodies recognize DNA. In the present work, to study the molecular mechanism of DNA recognition by antibodies, we have used anti-DNA IgGs from blood sera of patients with multiple sclerosis. A stepwise increase in ligand complexity approach was used to estimate the relative contributions of virtually every nucleotide unit of different single- (ss) and double-stranded (ds) oligonucleotides to their affinity for IgG fraction having high affinity to DNA-cellulose. DNA-binding site disposed on the heavy chain demonstrates higher affinity to different dNMPs (K_d  = 0.63μM-3.8μM) than the site located on the light chain (28μM-170μM). The heavy and light chains interact independently forming relatively strong contacts with 2 to 4 nucleotides of short homo- and hetero-d(pN)_2-9 . Then the increase in the affinity of different d(pN)_n became minimal, and at n ≥ 8 to 9, all dependencies reached plateaus: approximately 3.2nM to 20nM and approximately 200nM to 460nM for the heavy and light chains, respectively. A similar situation was observed for different ribooligonucleotides, in which their affinity is 6-fold to 100-fold lower than that for d(pN)_n . Transition from ss to ds d(pN)_n leads to a moderate increase in affinity of ligands to DNA-binding site of heavy chains, while light chains demonstrate the same affinity for ss and ds d(pN)_n . Long supercoiled DNA interacts with both heavy and light chains with affinity of approximately 10-fold higher than that for short oligonucleotides. The thermodynamic models were constructed to describe the interactions of IgGs light and heavy chains with DNA.

Comparison of Antibodies with Amylase Activity from Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

We have recently shown that IgGs from serum and cerebrospinal fluid (CSF) of MS patients are active in hydrolysis of DNA and myelin basic protein. According to literature data, anti-DNA and anti-MBP abzymes may promote important neuropathologic mechanisms in this chronic inflammatory disorder and in MS pathogenesis development. At the same time, the involvement of antibodies with amylase activity in the pathogenesis of any autoimmune disease has not yet been identified. Electrophoretically and immunologically homogeneous IgGs were obtained by a sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We are able to present the first unpredictable evidence showing that IgGs from CSF possess amylase activity and efficiently hydrolyze maltoheptaose; their average specific Ab activity is ~30-fold higher than that of antibodies from sera of the same MS patients. Specific average RA (SAA) for IgGs from healthy volunteers was approximately ~1000 lower than that for MS patients. In addition, it was shown that a relative SAA of total proteins of CSF (including Abs) ~15-fold lower than that for purified IgGs, while the relative SAA of the total sera protein is higher than that of sera IgGs by a factor of 1033. This result speaks in favor of the fact that amylolytic activity of CSF proteins is mainly caused by the activity of amylase abzymes. One cannot exclude, that amylase abzymes of CSF can play a, as yet unknown, role in the pathogenesis of MS. Some possible reasons of these findings are discussed.

Features of hydrolysis of specific and nonspecific globular proteins and oligopeptides by antibodies against viral integrase from blood of HIV-infected patients

It was shown previously that, as differentiated from canonical proteases, abzymes against myelin basic protein (MBP) from blood of patients with multiple sclerosis and systemic lupus erythematosus effectively cleaved only MBP, while antibodies (ABs) against integrase (IN) from blood of HIV-infected patients specifically hydrolyzed only IN. In this work, all sites of effective hydrolysis by anti-IN antibodies (IgG and IgM) of 25-mer oligopeptide (OP25) corresponding to MBP were identified using reversed-phase and thin-layer chromatographies and MALDI mass spectrometry. It was found that amino acid sequences of OP25 and other oligopeptides hydrolyzed by anti-MBP abzymes were partially homologous to some fragments of the full sequence of IN. Sequences of IN oligopeptides cleavable by anti-IN abzymes were homologous to some fragments of MBP, but anti-MBP abzymes could not effectively hydrolyze OPs corresponding to IN. The common features of the cleavage sites of OP25 and other oligopeptides hydrolyzed by anti-MBP and anti-IN abzymes were revealed. The literature data on hydrolysis of specific and nonspecific proteins and oligopeptides by abzymes against different protein antigens were analyzed. Overall, the literature data suggest that short OPs, including OP25, mainly interact with light chains of polyclonal ABs, which had lower affinity and specificity to the substrate than intact ABs. However, it seems that anti-IN ABs are the only one example of abzymes capable of hydrolyzing various oligopeptides with high efficiency (within some hours but not days). Possible reasons for the efficient hydrolysis of foreign oligopeptides by anti-IN abzymes from HIV-infected patients are discussed.

Why specific anti-integrase antibodies from HIV-infected patients can efficiently hydrolyze 21-mer oligopeptide corresponding to antigenic determinant of human myelin basic protein

Human immunodeficiency virus-infected patients possess anti-integrase (IN) catalytic IgGs and IgMs (abzymes), which, unlike canonical proteases, specifically hydrolyze only intact globular IN. Anti-myelin MBP abzymes from patients with multiple sclerosis and systemic lupus erythematosus efficiently hydrolyze only intact MBP. Anti-MBP and anti-IN abzymes do not hydrolyze several other tested control globular proteins. Here, we show that anti-IN abzymes efficiently hydrolyze a 21-mer oligopeptide (OP21) corresponding to one antigenic determinant (AGD) of MBP, whereas anti-MBP abzymes extremely poorly cleave oligopeptides corresponding to AGDs of IN. All sites of IgG-mediated and IgM-mediated proteolysis of OP21 by anti-IN abzymes were found for the first time by a combination of reverse phase and thin layer chromatography and mass spectrometry. Several clustered sites of OP21 cleavage were revealed and compared with the cleavage sites within the complete IN. Several fragments of OP21 had good homology with many fragments of the IN sequence. The active sites of anti-IN abzymes are known to be located on their light chains, whereas heavy chains are responsible for the affinity for protein substrates. Interactions of intact IN with both light and heavy chains of the abzymes provide high affinity for IN and the specificity of its hydrolysis. Our data suggest that OP21 interacts mainly with the light chains of polyclonal anti-IN abzymes, which possess lower affinity and specificity for substrate. The hydrolysis of the non-cognate OP21 oligopeptide may be also less specific than the hydrolysis of the globular IN because in contrast to previously described serine protease-like abzymes against different proteins, anti-IN abzymes possess serine, thiol, acidic, and metal-dependent protease activities.

Systemic lupus erythematosus: molecular cloning and analysis of recombinant DNase monoclonal κ light chain NGK-1

Because DNase antibodies are cytotoxic, enter the nucleus and cause DNA fragmentation inducing cell death by apoptosis, they can play an important role in the pathogenesis of different autoimmune pathologies and especially systemic lupus erythematosus (SLE). The interesting goal of catalytic antibodies research is not only to study a possible biological role of such antibodies, but also to develop in future new human and animal therapies that use the advantages offered by abzymes. An immunoglobulin κ light chain library from SLE patients was cloned into a phagemid vector. Phage particles displaying recombinant monoclonal antibody light chains (MLChs) capable of binding DNA were isolated by affinity chromatography on DNA-cellulose. Sixteen of the 46 MLChs efficiently hydrolyzed DNA; one MLCh (approximately 27-28kDa) was expressed in Escherichia coli and purified by metal chelating and gel filtration. MLCh NGK-1 was electrophoretically homogeneous and demonstrated a positive answer with mouse IgGs against light chains of human antibodies after western blotting. SDS-PAGE in a gel containing DNA demonstrated that the MLCh hydrolyzes DNA and is not contaminated by canonical DNases. The DNase MLCh was activated by several metal ions. The protein sequence of the DNase MLCh has homology with mammalian DNases I and shares with them several identical or similar (with the same side chain functionality) important amino acid residues, which are necessary for DNA hydrolysis and binding of Mg(2+) and Ca(2+) ions. The affinity of DNA for this first example of a MLCh (K(M) = 0.3 microM) was 150- to 200-fold higher than for human DNase I.

Systemic lupus erythematosus: molecular cloning of several recombinant DNase monoclonal kappa light chains with different catalytic properties

An immunoglobulin light chain phagemid library derived from peripheral blood lymphocytes of three patients with systemic lupus erythematosus was used. Phage particles displaying DNA binding light chains were isolated by affinity chromatography on DNA-cellulose, and the fraction eluted by an acidic buffer (pH 2.6) was used for preparation of individual monoclonal light chains (MLChs, 28 kDa). Thirty three of 687 individual colonies obtained were randomly chosen for study of MLCh DNase activity. Nineteen of 33 clones contained MLChs with DNase activity. Four preparations of MLChs were expressed in Escherichia coli in soluble form, purified by metal chelating chromatography followed by gel filtration, and studied in detail. Detection of DNase activity after SDS-PAGE in a gel containing DNA demonstrated that the four MLChs are not contaminated by canonical DNases. The MLChs demonstrated one or two pH optima. They were inactive after the dialysis against ethylenediaminetetraacetic acid but could be activated by several externally added metal ions; the ratio of relative activity in the presence of Mg(2+) , Mn(2+) , Ni(2+) , Ca(2+) , Zn(2+) , and Co(2+) was individual for each MLCh preparation. K(+) and Na(+) inhibited the DNase activity of various MLChs at different concentrations. Hydrolysis of DNA by all four MLCh was saturable and consistent with Michaelis-Menten kinetics. These clones are the first examples of recombinant MLChs possessing high affinity for DNA (Km  = 3-9 nM) and demonstrating high kcat values (3.4-6.9 min(-1) ). These observations suggest that the systemic lupus erythematosus light chain repertoire can serve as a source of new types of DNases.

Deoxyribonuclease activity of polyclonal IgGs: a putative serological marker in patients with spondyloarthritides

Antibodies executing catalytic activity are referred to as antibody enzymes or short "abzymes" and may have diagnostic relevance. Abzymes with deoxyribonuclease (DNase) activity have been demonstrated in patients with autoimmune and infectious diseases. Despite several reports on the occurrence of DNase abzymes in systemic autoimmune rheumatic diseases, conclusive data about DNase activity of antibodies in patients with spondyloarthritides (SpAs) are lacking. In recent cross-sectional studies evaluating levels of IgG DNase activity in patients with psoriatic arthritis (PsA), reactive arthritis (ReA), and ankylosing spondylitis (AS), DNase activity of IgG has been assessed by the rivanol clot method and confirmed by agarose gel electrophoresis. Remarkably, levels of IgG DNase activity were significantly higher in sera of SpA patients than those in control subjects. In patients with PsA, ReA, and AS, a positive correlation of DNase IgG activity with synovitis, disease activity, and stage of spondylitis was observed, respectively. Given the involvement of autoimmune reactions in cytolysis and connective tissue degradation in PsA, ReA, and to a lesser extent in AS, abzymes might have an impact on the pathophysiology of SpAs. Detection of IgG DNase activity in patients suffering from SpA represents an exciting new research field and may assist in the differential diagnosis of SpA.

Biochemical features of a catalytic antibody light chain, 22F6, prepared from human lymphocytes

Human antibody light chains belonging to subgroup II of germ line genes were amplified by a seminested PCR technique using B-lymphocytes taken from a human adult infected with influenza virus. Each gene of the human light chains was transferred into the Escherichia coli system. The recovered light chain was highly purified using a two-step purification system. Light chain 22F6 showed interesting catalytic features. The light chain cleaved a peptide bond of synthetic peptidyl-4-methyl-coumaryl-7-amide (MCA) substrates, such as QAR-MCA and EAR-MCA, indicating amidase activity. It also hydrolyzed a phosphodiester bond of both DNA and RNA. From the analysis of amino acid sequences and molecular modeling, the 22F6 light chain possesses two kinds of active sites as amidase and nuclease in close distances. The 22F6 catalytic light chain could suppress the infection of influenza virus type A (H1N1) of Madin-Darby canine kidney cells in an in vitro assay. In addition, the catalytic light chain clearly inhibited the infection of the influenza virus of BALB/c mice via nasal administration in an in vivo assay. In the experiment, the titer in the serum of the mice coinfected with the 22F6 light chain and H1N1 virus became considerably lowered compared with that of 22F6-non-coinfected mice. Note that the catalytic light chain was prepared from human peripheral lymphocyte and plays an important role in preventing infection by influenza virus. Considering the fact that the human light chain did not show any acute toxicity for mice, our procedure developed in this study must be unique and noteworthy for developing new drugs.

Hydrolysis of factor VIII mediated by catalytic antibodies occurs in haemophilia A patients with or without factor VIII inhibitors

The major complication of the substitutive treatment of haemophilia A (HA) is the development of antifactor VIII (FVIII) antibodies. Most of these antibodies neutralize FVIII procoagulant activity, and are identified as FVIII inhibitor. A subgroup of these antibodies, 'catalytic antibodies', catalyses the FVIII hydrolysis. We investigated the frequency and the activity of catalytic antibodies, according to the phenotype of HA and the presence or absence of FVIII inhibitor. IgG from 16 patients with inhibitor and 17 patients without inhibitor were purified. Rates of FVIII hydrolysis and inhibitor titres were evaluated. Anti-FVIII catalytic antibodies were detected in 63.6% of patients with HA, irrespective of the HA phenotype and the presence of FVIII inhibitor. The frequency was significantly higher for severe HA patients (73.3%) and patients with inhibitor (87.5%), but their FVIII-proteolytic activity was not significantly different from patients with mild or moderate HA and patients without inhibitor. The evolution of both catalytic and inhibitory activities was studied for 11 patients with FVIII inhibitor. We observed two profiles. In the profile 1, 18.2% of patients, the catalytic activity and the inhibitor titre coevolved. In contrast, a dissociated evolution of these two parameters was observed in 72.8% patients in profile 2. These data confirm the importance of anti-FVIII catalytic activity in patients with severe, moderate and mild HA. Interestingly, most of the patients presented a dissociated profile, suggesting that anti-FVIII antibodies might not systematically act as FVIII inhibitors.

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.

Multiple sites of the cleavage of 17- and 19-mer encephalytogenic oligopeptides corresponding to human myelin basic protein (MBP) by specific anti-MBP antibodies from patients with systemic lupus erythematosus

In contrast to canonical proteases, myelin basic protein (MBP)-Sepharose-purified IgG from multiple sclerosis (MS) and systemic lupus erythematosus (SLE) patients efficiently hydrolyze only MBP, but not many other tested proteins. It was shown that anti-MBP SLE IgGs cleave nonspecific tri- and tetrapeptides with an extremely low efficiency and cannot efficiently hydrolyse longer oligopeptides corresponding to antigenic determinants (AGDs) of HIV-1 integrase. To identify all sites of IgG-mediated proteolysis corresponding to two AGDs of MBP, we have used a combination of reverse-phase chromatography (RPhC), MALDI spectrometry, and TLC to analyze the cleavage products of two (17- and 19-mer) encephalytogenic oligopeptides corresponding to these AGDs. Both oligopeptides contained several clustered major and minor sites of cleavage. The active sites of anti-MBP abzymes are localized on their light chains, while the heavy chains are responsible for the affinity of protein substrates. Interactions of intact globular proteins with both light and heavy chains of abzymes provide high specificity of MBP hydrolysis. The affinity of anti-MBP abzymes for intact MBP was ∼10(3)-fold higher than for the oligopeptides. The data suggest that both oligopeptides interact mainly with the light chain of different monoclonal abzymes of total pool of IgGs, which possesses lower affinity for substrates, and therefore, depending on the oligopeptide sequences, their hydrolysis may be less specific.

IgGs containing light chains of the λ- and κ- type and of all subclasses (IgG1-IgG4) from the sera of patients with systemic lupus erythematosus hydrolyze myelin basic protein

Human myelin basic protein (hMBP)-hydrolyzing activity was recently shown to be an intrinsic property of antibodies from systemic lupus erythematosus (SLE) patients. Here, we present the first evidence demonstrating a significant diversity of different fractions of polyclonal IgGs (pIgGs) from SLE patients in their affinity for hMBP and in the ability of pIgGs to hydrolyze hMBP at different optimal pH values (5.3-9.5); the pH profiles of IgG1, IgG2, IgG3 and IgG4 were unique. IgGs containing the λ-type of light chains demonstrated higher relative activities (RAs) in the hydrolysis of hMBP and its oligopeptides (OPs) than κ-IgGs. IgGs of all four subclasses were catalytically active; their RAs in the hydrolysis of hMBP increased in the following order: IgG4 < IgG2 < IgG3 < IgG1. Metal-dependent proteolytic activity of λ-IgG, IgG1, IgG2 and IgG3 was higher than their serine protease-like activity, while these activities of κ-IgG were comparable. Phenylmethylsulfonylfluoride had almost no effect on the activity of IgG4, while EDTA significantly suppressed its activity. The RAs of λ-IgG in the hydrolysis of four OPs corresponding to different cleavage sites of hMBP were remarkably higher than those for κ-IgGs. IgG1-IgG4 demonstrated different RAs and patterns of hydrolysis of these four OPs. Although combination of Ca²⁺ plus Mg²⁺ was the best in the activation of IgG1 and IgG2, IgG3 and IgG4 demonstrated the highest activity in the presence of Ca²⁺ plus Co²⁺. The ratio of the RAs of λ-IgG, κ-IgG and IgG1-IgG4 preparations in all analyzed cases was individual for each preparation.

Diversity of integrase-hydrolyzing IgGs and IgMs from sera of HIV-infected patients

It was previously shown that small fractions of IgGs and IgMs from the sera of AIDS patients specifically hydrolyze only HIV integrase (IN) but not many other tested proteins. Here we present evidence showing that these IgGs and IgMs are extreme catalytically heterogeneous. Affinity chromatography on IN-Sepharose using elution of IgGs (or IgMs) with different concentration of NaCl and acidic buffer separated catalytic antibodies (ABs) into many AB subfractions demonstrating different values of K(m) for IN and k(cat). Nonfractionated IgGs and IgMs possess serine-, thiol-, acidic-like, and metal-dependent proteolytic activity. Metal-dependent activity of abzymes increases in the presence of ions of different metals. In contrast to canonical proteases having one pH optimum, initial nonfractionated IgGs and IgMs demonstrate several optima at pH from 3 to 10. The data obtained show that IN-hydrolyzing polyclonal IgG and IgM of HIV-infected patients are cocktails of anti-IN ABs with different structure of the active centers possessing various affinity to IN, pH optima, and relative rates of the specific substrate hydrolysis.

Affinity and catalytic heterogeneity and metal-dependence of polyclonal myelin basic protein-hydrolyzing IgGs from sera of patients with systemic lupus erythematosus

It was shown using enzyme-linked immunosorbent assay (ELISA) that titers of antibodies against human myelin basic protein (hMBP) in systemic lupus erythematosus (SLE) patients 4.2-fold higher than in healthy individuals, but 2.1-fold lower than in patients with multiple sclerosis (MS). Approximately 86% electrophoretically and immunologically homogeneous SLE immunoglobulin Gs (IgGs) purified using several affinity resins including Sepharose with immobilized hMBP specifically hydrolyze only hMBP but not many other tested proteins. Several rigid criteria were applied to show that the hMBP-hydrolyzing activity is an intrinsic property of SLE IgGs but not from healthy donors. In contrast to MS IgGs, abzymes from SLE patients are more sensitive to ethylenediaminetetraacetic acid and less sensitive to specific inhibitors of serine-like proteases. We present the first evidence demonstrating a significant diversity of different fractions of SLE IgGs in their affinity for hMBP-Sepharose, the ability of IgGs to hydrolyze hMBP at different optimal pHs (5-10) and be activated by different metal ions: Ca(2+) > Mg(2+) ≥ Co(2+) ≥ Fe(2+) ≥ Ni(2+) ≥ Zn(2+) ≥ Cu(2+) ≥ Mn(2+) . Combinations of Ca(2+) + Mg(2+) and Ca(2+) + Co(2) lead to a significant increase in the antibody proteolytic activity as compared with Ca(2+) , Co(2+) , or Mg(2+) ions taken separately. Our findings suggest that the immune systems of individual SLE similar to MS patients can generate a variety of anti-hMBP abzymes with different catalytic properties, which can attack hMBP of myelin-proteolipid shell of axons and play an important role in pathogenesis not only MS but also SLE patients.

DNase, RNase, and phosphatase activities of antibodies formed upon immunization by DNA, DNase I, and DNase II

Relative DNase, RNase (efficiency of hydrolysis of ribo- and deoxyribooligonucleotides (ON)), and phosphatase (removal of the ON 5' terminal phosphate) catalytic activities of antibodies (AB) obtained after rabbit immunization by DNA, DNase I, and DNase II were compared. It is shown that electrophoretically homogeneous preparations of polyclonal AB from non-immunized rabbits did not exhibit such activities. Immunization of rabbits by DNA, DNase I, and DNase II results in generation of IgG abzymes that exhibit high activity in the ON hydrolysis reaction and even higher activity in cleavage of 5' terminal phosphate of ON. In this case K(m) values for supercoiled plasmid DNA and ON found in reactions of their AB-dependent nuclease hydrolysis and phosphatase cleavage of 5' terminal phosphate differ by 2-4 orders of magnitude. This shows that nuclease and phosphatase activities belong to different abzyme fractions within polyclonal AB. Thus, in this work data indicative of the possibility of a formation of antibodies exhibiting phosphatase activity after immunization of animals with DNA, DNase I, and DNase II, were obtained for the first time. Possible reasons for production of AB with phosphatase activity after immunization of rabbits with these immunogens are discussed.

IgGs containing light chains of the lambda and kappa type and of all subclasses (IgG1-IgG4) from sera of patients with multiple sclerosis hydrolyze DNA

We present the first evidence demonstrating that small fractions of IgGs of all four subclasses (IgG1-IgG4) are catalytically active in the hydrolysis of DNA and on average their relative activity (nM supercoiled DNA/1mg IgG/1 h) increases in the order: IgG1 (0.58) < IgG2 (0.94) < IgG3 (1.4) < IgG4 (4.1), while their approximate relative contribution to the total activity of abzymes increases in the order: IgG1 (6.9%) < IgG3 (9.3%) < IgG2 (18.2%) < IgG4 (65.6%). On average IgGs containing light chains of the lambda-type are severalfold more active in the hydrolysis of DNA than IgGs with light chains of the kappa-type. Using different physicochemical methods of antibody analysis we have shown that the immune system of multiple sclerosis patients generates a variety of anti-DNA abzymes of different type and with different catalytic properties, which can play an important role in multiple sclerosis pathogenesis.

Diversity of DNA-hydrolyzing antibodies from the sera of autoimmune-prone MRL/MpJ-lpr mice

It has been shown for the first time that polyclonal IgG abzymes (Abzs) with DNase activity from the sera of autoimmune-prone MRL/MpJ-lpr mice can be separated by isoelectric focusing into many subfractions having the isoelectric points (pI) from 4.5 to 9, with the maximal activity for Abzs with pI = 6.5-9.0. Affinity chromatography on DNA-cellulose separated DNase IgGs into many subfractions demonstrating a range of affinities for DNA and different levels of the relative DNase activities (RDA) due to intrinsically bound metals and after addition of external Mg(2+) , Mn(2+) , Ca(2+), and Mg(2+) +Ca(2+). Some fractions significantly increase RDAs in the presence of external ions (Mg(2+) + Ca(2+)  > Mg(2+)  > Mn(2+)  > Ca(2+)), while each of this cofactor can also inhibit or have no influence on the RDAs of another fractions. It is known that complexes of DNA with histones and other proteins of apoptotic cells are the primary immunogens in systemic lupus erythematosus (SLE). Bovine serum albumin (BSA) and methylated BSA (mBSA) increase the RDAs of only some fractions, while have no effect or inhibit other IgG fractions. The ratio of the RDAs in the presence of all metal ions, BSA, and mBSA was individual for every abzyme fraction. Mn(2+) and Ca(2+) stimulated accumulation of only relaxed form of supercoiled DNA (scDNA) in the case of all subfractions, while in the presence of Mg(2+) antibodies (Abs) of some subfractions (and in the presence of Mn(2+) +Ca(2+) all subfractions) produced relaxed DNA (rDNA) and linear DNA (linDNA) in a variable extent. The data obtained show that the polyclonal Abzs of mice may be a cocktail of Abs directly to DNA, RNA, and their complexes with proteins and anti-idiotypic Abs to active centers of different nucleases. The diversity of the physicochemical and kinetic characteristics of the Abzs seems to be significantly widened when pre-diseased mice spontaneously develop the disease.

Peculiarities of abzymes from sera and milk of healthy donors and patients with autoimmune and viral diseases

The detection of catalytic activity of antibodies is the earliest indicator of development of autoimmune diseases (AID). In early stages of AID, the repertoire of abzymes with various properties is relatively small, but it is greatly increased during their development. Catalytic diversity of the abzymes includes DNase, RNase, ATPase, and oxidoreductase activities; there are antibodies phosphorylating proteins, lipids, and polysaccharides. This review summarizes new data on abzyme heterogeneity and possible reasons for this phenomenon. A possible role of abzymes and their exceptional multiplicity in the pathogenesis of different AID is discussed.

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.