Catalytic heterogeneity of polyclonal DNA-hydrolyzing antibodies from the sera of patients with multiple sclerosis

Some structural features of the peptide profile of myelin basic protein-hydrolyzing antibodies in schizophrenic patients

The antibodies of schizophrenic patients that hydrolyze myelin basic protein (MBP) have been actively studied recently, but the mechanism of the catalytic properties of immunoglobulin molecules remains unknown. Determination of specific immunoglobulin sequences associated with the high activity of MBP proteolysis will help to understand the mechanisms of abzyme catalysis. In the course of comparative mass spectrometric analysis of IgG peptides from the blood serum of patients with acute schizophrenia and healthy people, 12 sequences were identified, which were found only in antibodies that hydrolyze MBP. These sequences belong to IgG heavy chains and κ- and λ-type light chains, with eight of them belonging to variable domains. The content of peptides from the variable regions of the light chains does not correlate with the proteolytic activity of IgG to MBP in patients with schizophrenia, whereas for two sequences from the variable regions of the heavy chains (FQ(+0.98)GWVTMTR and *LYLQMN(+0.98)SLR), an increase in activity with increasing their concentration. The results suggest that these sequences may be involved in one way or another in MBP hydrolysis.

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

Histones play vital roles in chromatin function and gene transcription; however, they are very harmful in the intercellular space because they stimulate systemic inflammatory and toxic responses. Myelin basic protein (MBP) is the major protein of the axon myelin-proteolipid sheath. Antibodies-abzymes with various catalytic activities are specific features of some autoimmune diseases. IgGs against individual histones (H2A, H1, H2B, H3, and H4) and MBP were isolated from the blood of experimental-autoimmune-encephalomyelitis-prone C57BL/6 mice by several affinity chromatographies. These Abs-abzymes corresponded to various stages of EAE development: spontaneous EAE, MOG, and DNA-histones accelerated the onset, acute, and remission stages. IgGs-abzymes against MBP and five individual histones showed unusual polyreactivity in the complex formation and enzymatic cross-reactivity in the specific hydrolysis of the H2A histone. All the IgGs of 3-month-old mice (zero time) against MBP and individual histones demonstrated from 4 to 35 different H2A hydrolysis sites. The spontaneous development of EAE over 60 days led to a significant change in the type and number of H2A histone hydrolysis sites by IgGs against five histones and MBP. Mice treatment with MOG and the DNA-histone complex changed the type and number of H2A hydrolysis sites compared to zero time. The minimum number (4) of different H2A hydrolysis sites was found for IgGs against H2A (zero time), while the maximum (35) for anti-H2B IgGs (60 days after mice treatment with DNA-histone complex). Overall, it was first demonstrated that at different stages of EAE evolution, IgGs-abzymes against individual histones and MBP could significantly differ in the number and type of specific sites of H2A hydrolysis. The possible reasons for the catalytic cross-reactivity and great differences in the number and type of histone H2A cleavage sites were analyzed.

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

Histones have vital roles in chromatin functioning and gene transcription. At the same time, they are pernicious in intercellular space because they stimulate systemic inflammatory and toxic responses. Myelin basic protein (MBP) is the major protein of the axon myelin–proteolipid sheath. Antibody-abzymes with various catalytic activities are specific features of some autoimmune diseases. IgGs against five individual histones (H2B, H1, H2A, H3, and H4) and MBP were isolated from the blood of experimental autoimmune encephalomyelitis-prone C57BL/6 mice by affinity chromatography. Abzymes corresponding to various stages of EAE development, including spontaneous EAE, myelin oligodendrocyte glycoprotein (MOG)- and DNA-histone complex-accelerated onset, as well as acute and remission stages, were analyzed. IgG-abzymes against MBP and five individual histones showed unusual polyreactivity in complex formation and enzymatic cross-reactivity in the specific hydrolysis of H2B histone. All IgGs against MBP and individual histones in 3-month-old mice (zero time) demonstrated from 4 to 11 different H2B hydrolysis sites. Spontaneous development of EAE during 60 days led to a significant change in the type and number of H2B hydrolysis sites by IgGs against the five histones and MBP. Mouse treatment with MOG and DNA-histone complex changed the type and number of H2B hydrolysis sites compared to zero time. The minimum number (3) of different H2B hydrolysis sites was found for IgGs against H3 20 days after mouse immunization with DNA-histone complex, whereas the maximum number (33) for anti-H2B IgGs was found 60 days after mouse treatment with DNA-histone complex. Overall, this is the first study to demonstrate that at different stages of EAE evolution, IgG-abzymes against five individual histones and MBP could significantly differ in the specific sites and number of H2B hydrolysis sites. Possible reasons for the catalytic cross-reactivity and significant differences in the number and type of histone H2B cleavage sites were analyzed.

Experimental Autoimmune Encephalomyelitis of Mice: IgGs from the Sera of Mice Hydrolyze miRNAs

It was shown that the spontaneous development of experimental encephalomyelitis (EAE) in C57BL/6 mice occurs due to changes in the profile of bone marrow stem cells differentiation. This leads to the appearance of lymphocytes producing antibodies-abzymes that hydrolyze DNA, myelin basic protein (MBP), and histones. The activity of abzymes in the hydrolysis of these auto-antigens slowly but constantly increases during the spontaneous development of EAE. Treatment of mice with myelin oligodendrocyte glycoprotein (MOG) leads to a sharp increase in the activity of these abzymes with their maximum at 20 days (acute phase) after immunization. In this work, we analyzed changes in the activity of IgG-abzymes hydrolyzing (pA)₂₃, (pC)₂₃, (pU)₂₃, and six miRNAs (miR-9-5p, miR-219a-5p, miR-326, miR-155-5p, miR-21-3p, and miR-146a-3p) before and after mice immunization with MOG. Unlike abzymes hydrolyzing DNA, MBP, and histones, the spontaneous development of EAE leads not to an increase but to a permanent decrease of IgGs activity of hydrolysis of RNA-substrates. Treatment of mice with MOG resulted in a sharp but transient increase in the activity of antibodies by day 7 (onset of the disease), followed by a sharp decrease in activity 20-40 days after immunization. A significant difference in the production of abzymes against DNA, MBP, and histones before and after mice immunization with MOG with those against RNAs may be since the expression of many miRNAs decreased with age. This can lead to a decrease in the production of antibodies and abzymes that hydrolyze miRNAs with age mice.

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.

Natural IgG against S-Protein and RBD of SARS-CoV-2 Do Not Bind and Hydrolyze DNA and Are Not Autoimmune

Since the onset of the COVID-19 pandemic, numerous publications have appeared describing autoimmune pathologies developing after a coronavirus infection, with several papers reporting autoantibody production during the acute period of the disease. Several viral diseases are known to trigger autoimmune processes, and the appearance of catalytic antibodies with DNase activity is one of the earliest markers of several autoimmune pathologies. Therefore, we analyzed whether IgG antibodies from blood plasma of SARS-CoV-2 patients after recovery could bind and hydrolyze DNA. We analyzed how vaccination of patients with adenovirus Sputnik V vaccine influences the production of abzymes with DNase activity. Four groups were selected for the analysis, each containing 25 patients according to their relative titers of antibodies to S-protein: with high and median titers, vaccinated with Sputnik V with high titers, and a control group of donors with negative titers. The relative titers of antibodies against DNA and the relative DNase activity of IgGs depended very much on the individual patient and the donor, and no significant correlation was found between the relative values of antibodies titers and their DNase activity. Our results indicate that COVID-19 disease and vaccination with adenoviral Sputnik V vaccine do not result in the development or enhancement of strong autoimmune reactions as in the typical autoimmune diseases associated with the production of anti-DNA and DNA hydrolyzing antibodies.

Experimental Autoimmune Encephalomyelitis of Mice: Enzymatic Cross Site-Specific Hydrolysis of H4 Histone by IgGs against Histones and Myelin Basic Protein

Histones play vital roles in chromatin functioning and gene transcription, but in intercellular space, they are harmful due to stimulating systemic inflammatory and toxic responses. Myelin basic protein (MBP) is the most important protein of the axon myelin–proteolipid sheath. Antibodies-abzymes with different catalytic activities are critical and specific features of some autoimmune diseases. Five IgG preparations against histones (H4, H1, H2A, H2B, and H3) and against MBP corresponding to different spontaneous, MOG (myelin oligodendrocyte glycoprotein of mice), and DNA–histones that accelerated onset, acute, and remission stages of experimental autoimmune encephalomyelitis (EAE; model of human multiple sclerosis) development were obtained from EAE-prone C57BL/6 mice by several affinity chromatographies. IgG-abzymes against five histones and MBP possess unusual polyreactivity in complexation and catalytic cross-reactivity in the hydrolysis of histone H4. IgGs against five histones and MBP corresponding to 3 month-old mice (zero time) in comparison with Abs corresponding to spontaneous development of EAE during 60 days differ in type and number of H4 sites for hydrolysis. Immunization of mice with MOG and DNA–histones complex results in an acceleration of EAE development associated with an increase in the activity of antibodies in H4 hydrolysis. Twenty days after mouse immunization with MOG or DNA–histones complex, the IgGs hydrolyze H4 at other additional sites compared to zero time. The maximum number of different sites of H4 hydrolysis was revealed for IgGs against five histones and MBP at 60 days after immunization of mice with MOG and DNA–histones. Overall, it first showed that at different stages of EAE development, abzymes could significantly differ in specific sites of H4 hydrolysis.

Cell Differentiation and Proliferation in the Bone Marrow and Other Organs of 2D2 Mice during Spontaneous Development of EAE Leading to the Production of Abzymes

The exact cellular and molecular mechanisms of multiple sclerosis and other autoimmune diseases have not been established. Autoimmune pathologies are known to be associated with faults in the immune system and changes in the differentiation profiles of bone marrow stem cells. This study analyzed various characteristics of experimental autoimmune encephalomyelitis (EAE) in 2D2 mice. Differentiation profiles of six hematopoietic stem cells of bone marrow were found to significantly differ in 2D2 male and female mice during the spontaneous development of EAE. In addition, we found various properties of B and T cells, CD4+ and CD8+ lymphocytes in blood and several organs (bone marrow, spleen, thymus, and lymph nodes) of 2D2 male and female mice to be considerably different. These changes in hematopoietic stem cells differentiation profiles and level of lymphocyte proliferation in various organs of 2D2 mice were found to induce the production of IgGs against DNA, myelin basic protein, and myelin oligodendrocyte glycoprotein, increasing the number of autoantibodies hydrolyzing these substrates. We compared the changes of these immunological and biochemical parameters in 2D2 mice with those of mice of two other lines (Th and C57BL/6), also prone to spontaneous development of EAE. Some noticeable and even extreme variations were found in the time-related development of parameters between male and female mice of 2D2, Th, and C57BL/6 lines. Despite some differences, mice of all three lines demonstrated the changes in hematopoietic stem cells profiles, lymphocyte content, and production of catalytic autoantibodies. Given that these changes are harmful to mice, we believe them to cause the development of experimental autoimmune encephalomyelitis.

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.

Concentration of cell-free DNA in different tumor types

Introduction: Cell-free DNA (cfDNA) circulates in the blood for a long time. The levels of cfDNA in the blood are assayed in cancer diagnostics because they are closely related to the tumor burden of patients.Areas covered: cfDNA escapes the action of DNA-hydrolyzing enzymes, being a part of supramolecular complexes or interacting with the plasma membrane of blood cells. cfDNA has heterogeneous size and composition, which impose various restrictions on both isolation methods and subsequent analysis. cfDNA concentration and structural changes with the development of diseases highlight the high potential of cfDNA as a diagnostic and prognostic marker. The concentration of cfDNA released in the blood by tumor cells determines the specificity of such diagnostics and the required blood volume. The present review aimed to synthesize the available data on cfDNA concentration in the cancer patient's blood as well as pre-analytical, analytical, and biological factors, which interfere with cfDNA concentration.Expert opinion: The concentration of cfDNA and tumor cell DNA (ctDNA), and the over-presentation of DNA loci in cfDNA must be considered when looking for tumor markers. Some inconsistent data on cfDNA concentrations (like those obtained by different methods) suggest that the study of cfDNA should be continued.

Igg-Dependent Hydrolysis of Myelin Basic Protein of Patients with Different Courses of Schizophrenia

The level hydrolysis of myelin basic protein (MBP) by IgG in patients with schizophrenia was studied depending on the clinical features and course of the disease. The patients were grouped according to type of schizophrenia and type of disease course. We found that IgGs isolated and purified from sera of schizophrenia patients' blood hydrolyses human MBP, and the level of this hydrolysis significantly exceeds that of healthy individuals. Detection of protease activity corresponding only to intact IgGs in polyacrylamide gel fragments, together with data of gel filtration of antibodies under conditions of “acid shock” (concordance of optical density profile of IgG with profile of MBP-hydrolyzing activity) and with the absence of any other proteins and bands in gradient SDS-PAGE and in PVDF membrane provides direct evidence that the IgGs from the schizophrenia patients have MBP-hydrolyzing activity. The antibodies-specific proteolytic activity of patients with acute schizophrenia (1.026 [0.205; 3.372] mg MBP/mg IgG/h) significantly exceeds the activity of IgG in patients in remission (0.656 [0.279; 0.873] mg MBP/mg IgG/h) and in healthy individuals (0.000 [0.00; 0.367] mg MBP/mg IgG/h). When comparing the specific activity in patients with different types of disease course, we have found that patients with a continuous course of paranoid schizophrenia (1.810 [0.746; 4.101 mg MBP/mg IgG/h]) had maximal activity values. It can be assumed that the increase in the activity of MBP-hydrolyzing antibodies is due to the activation of humoral immunity in acute schizophrenia.

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.

Antibodies from the Sera of Multiple Sclerosis Patients Efficiently Hydrolyze Five Histones

It is known that intranuclear histones can be pernicious after entering to the extracellular space. In addition, the immunization of animals with exogenous histones leads to systemic inflammatory and toxic reactions. Abzymes—autoantibodies with enzymatic activities—are the distinctive feature of autoimmune diseases and they can be especially dangerous to humans. Here, electrophoretically homogeneous IgGs were isolated from sera of patients with multiple sclerosis (MS) by chromatography on several affinity sorbents. We present evidence that sera of all MS patients contain autoantibodies against histones and 73% of IgGs purified from the sera of 59 MS patients efficiently hydrolyze from one to five histones: H1, H2a, H2b, H3, and H4. The relative average efficiency of the histones hydrolysis was ~3.9-fold higher than that for healthy donors. The relative average activity of IgGs depends on the type of MS and decreased approximately in the following order: debut of MS, secondary progressive multiple sclerosis, remitting multiple sclerosis, remittent progressive multiple sclerosis. Similar to proteolytic abzymes of patients with several autoimmune diseases, histone-hydrolyzing IgGs from MS patients were inhibited in the presence of specific inhibitors of serine and of metal-dependent proteases, but an unexpected significant inhibition of the activity by inhibitors of thiol-like and especially acidic proteases was observed. Since IgGs can efficiently hydrolyze histones, a negative role of abzymes in the development of MS cannot be excluded.

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.

Changes in haematopoietic progenitor colony differentiation and proliferation and the production of different abzymes in EAE mice treated with DNA

Immunization of experimental autoimmune encephalomyelitis (EAE)‐prone C57BL/6 mice with MOG_35‐55 (a model used to study aspects of human multiple sclerosis) is known to lead to the production of various abzymes. The production of catalytic IgGs that can efficiently hydrolyse myelin basic protein (MBP), MOG and DNA is associated with changes in the profile of differentiation and level of proliferation of mice bone marrow haematopoietic stem cells (HSCs). As MOG simulates the production of abzymes with high DNase activity, we compared the effects of DNA and MOG immunization on EAE‐prone mice. In contrast to MOG, immunization with DNA leads to a suppression of proteinuria, a decrease in the concentrations of antibodies to MOG and DNA and a reduction in abzyme production. Immunization with DNA only resulted in a significant increase in DNase activity over 40 days where it became 122‐fold higher than before immunization, and fivefold higher when comparing to the maximal activity obtained after MOG treatment. DNA and MOG immunization had different effects on the differentiation profiles of HSCs, lymphocyte proliferation, and the level of apoptosis in bone marrow and other organs of mice. The data indicate that for C57BL/6 mice, DNA may have antagonistic effects with respect to MOG immunization. The usually fast immune response following MOG injection in C57BL/6 mice is strongly delayed after immunization with DNA, which is probably due to a rearrangement of the immune system following the response to DNA.

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.

Changes in different parameters, lymphocyte proliferation and hematopoietic progenitor colony formation in EAE mice treated with myelin oligodendrocyte glycoprotein

Myelin oligodendrocyte glycoprotein (MOG) is an antigen of the myelin sheath, which may trigger immune cell responses and the production of auto-antibodies in multiple sclerosis (MS). In this study, we used MOG(35-55) -induced experimental autoimmune encephalomyelitis (EAE), a model of human MS, to assess the production of catalytically active immunoglobulin G (IgG) antibodies or abzymes which have been shown to be present in sera of patients with several autoimmune diseases. Here, we show that IgGs from the sera of control C57BL/6 mice are catalytically inactive. During development of EAE, a specific reorganization of the immune system of mice occurred leading to a condition which was associated with the generation of catalytically active IgGs hydrolysing DNA, myelin basic protein (MBP) and MOG which was associated with increased proteinuria, changes in differentiation of mice bone marrow hematopoietic stem cells (HSCs) and an increase in proliferation of lymphocytes in bone marrow, spleen and thymus as well as a significant suppression of cell apoptosis in these organs. The strongest alterations were found in the early disease phase (18-24 days after immunization) and were less pronounced in later EAE stages (40 days after EAE induction). We conclude that a significant increase in DNase and proteolytic activities of antibodies may be considered the earliest statistically significant marker of MOG-induced EAE in mice. The possible differences in immune system reorganizations during preclinical phases of the disease, acute and late EAE, leading to production of different auto-antibodies and abzymes as well other changes are discussed.

Generation of blood circulating DNA: the sources, peculiarities of circulation and structure

Extracellular nucleic acids (exNA) were described in blood of both healthy and illness people as early as in 1948, but staied overlooked until middle 60-th. Starting from the beginning of new millennium and mainly in the last 5 years exNA are intensively studied. Main attention is directed to investigation of exNA as the source of diagnostic material whereas the mechanisms of their generation, as well as mechanisms to providing long-term circulation of exNA in the bloodstream are not established unambiguously. According to some authors, the main source of circulating nucleic acids in blood are the processes of apoptosis and necrosis, while others refer to the possible nucleic acid secretion by healthy and tumor cells. Circulating DNA were found to be stable in the blood for a long time, escaping from the action of DNA hydrolyzing enzymes and are apparently packed in different supramolecular complexes. This review presents the opinions of various authors and evidence in favor of all the theories describingappearance of extracellular DNA, the features of the circulation and structure of the extracellular DNA and factors affecting the time of DNA circulation in blood

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.

Comparison of DNA-hydrolyzing antibodies from the cerebrospinal fluid and serum of patients with multiple sclerosis

It was found that high-affinity anti-DNA antibodies were one of the major components of the intrathecal IgG response in multiple sclerosis (MS) patients [Williamson et al., PNAS, 2001]. Recently we have shown that IgGs from the sera of MS patients are active in the hydrolysis of DNA. Here we have shown, for the first time, that average concentration of total proteins (132-fold), total IgGs (194-fold) and anti-DNA antibodies (200-fold) in the sera is significantly higher than that in the cerebrospinal fluid (CSF) of fifteen MS patients. The relative activities of total protein from sera and CSFs varied remarkably from patient to patient. It was surprising that the specific DNase activity of the total protein of CSF reparations were 198-fold higher than the serum ones. Electrophoretically and immunologically homogeneous IgGs were obtained by sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We present first evidence showing that IgGs from CSF not only bind but efficiently hydrolyze DNA and that average specific DNase activity of homogeneous antibodies from CSF is unpredictably ∼49-fold higher than that from the sera of the same MS patients. Some possible reasons of these findings are discussed. We suggest that DNase IgGs of CSF may promote important neuropathologic mechanisms in this chronic inflammatory disorder and MS pathogenesis development.

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.

Multiple sites of the cleavage of 21- and 25-mer encephalytogenic oligopeptides corresponding to human myelin basic protein (MBP) by specific anti-MBP antibodies from patients with systemic lupus erythematosus

IgGs from patients with multiple sclerosis and systemic lupus erythematosus (SLE) purified on MBP-Sepharose in contrast to canonical proteases hydrolyze effectively only myelin basic protein (MBP), but not many other tested proteins. Here we have shown for the first time that anti-MBP SLE IgGs hydrolyze nonspecific tri- and tetrapeptides with an extreme low efficiency and cannot effectively hydrolyze longer 20-mer nonspecific oligopeptides corresponding to antigenic determinants (AGDs) of HIV-1 integrase. At the same time, anti-MBP SLE IgGs efficiently hydrolyze oligopeptides corresponding to AGDs of MBP. All sites of IgG-mediated proteolysis of 21-and 25-mer encephalytogenic oligopeptides corresponding to two known AGDs of MBP were found by a combination of reverse-phase chromatography, TLC, and MALDI spectrometry. Several clustered major, moderate, and minor sites of cleavage were revealed in the case of 21- and 25-mer oligopeptides. The active sites of anti-MBP abzymes are localised on their light chains, while 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 affinity to MBP and specificity of this protein hydrolysis. The affinity of anti-MBP abzymes for intact MBP is approximately 1000-fold higher than for the oligopeptides. The data suggest that all oligopeptides interact mainly with the light chains of different monoclonal abzymes of total pool of IgGs, which possesses a lower affinity for substrates, and therefore, depending on the oligopeptide sequences, their hydrolysis may be less specific than globular protein and can occur in several sites.

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.

Do proteolytic antibodies complete the panoply of the autoimmune response in acquired haemophilia A?

Acquired haemophilia A (AHA) is a rare bleeding disorder characterized by the sudden generation of autoantibodies against factor VIII (FVIII) in individuals with no previous history of abnormal haemostasis. Understanding the pathogenesis of this disease has been hampered by the rarity of the patients and the difficulty in obtaining biological material from untreated patients. Still, progress has been made recently in understanding the pathogenesis of AHA. In particular, the importance of CD4(+) T cells in AHA development has been documented and the epitopes targeted by T cells on FVIII have been delineated. Accordingly, a polymorphism in the cytotoxic T-lymphocyte-associated protein 4 gene (CTLA4), known to participate in the regulation of CD4(+) T-cell responses, and a preferential usage of certain human leukocyte antigen class II haplotypes, have been associated with the disease. Recent findings have documented the presence of immunoglobulin G (IgG) with proteolytic activity against FVIII and factor IX (FIX) in patients with AHA. While FVIII-hydrolysing IgG has been shown to inactivate FVIII, FIX-hydrolysing IgG from AHA patients activate FIX in vitro. Here, we describe the latest findings on the immuno-pathogenesis of AHA, with a special focus on the potential role played by antibodies endowed with proteolytic properties.

Autoantibodies with enzymatic properties in human autoimmune diseases

Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. In addition to this plethora of functions, some antibodies express enzymatic activity. Antibodies endowed with enzymatic properties have been described in human autoimmune manifestations in a variety of disorders such as autoimmune thyroiditis, systemic erythematosus (SLE), scleroderma, rheumatoid arthritis (RA), multiple sclerosis (MS) and acquired hemophilia (AH). Antibodies isolated from these conditions were able to specifically hydrolyze thyroglobulin, DNA, RNA, myelin basic protein (MBP), and factor VIII (FVIII) or factor IX (FIX), respectively. The therapeutic relevance of these findings is 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.

Antibody-dependent cell-mediated cytotoxicity- and complement-dependent cytotoxicity-independent bactericidal activity of an IgG against Pseudomonas aeruginosa O6ad

In addition to Ag recognition, some Abs are capable of killing target organisms in the absence of phagocytes and complement. In this study, we report that an anti-Pseudomonas aeruginosa O6ad LPS IgG(1), tobacco-expressed human S20 IgG(1) (te-hS20), as well as its recombinant Fab and single-chain variable fragment (scFv) fragments have cellular- and complement-independent bactericidal activity. te-hS20 and its Fab and scFv significantly reduced viability of P. aeruginosa O6ad in dose- and time-dependent manners in vitro and also showed lower levels of bactericidal activity against P. aeruginosa PAO1, but had no activity against P. aeruginosa O10, Escherichia coli TG1, and Streptococcus agalactiae. The H chain and its Fd fragment both had significant Ag-binding and bactericidal activities against P. aeruginosa O6ad. Bactericidal activity was completely inhibited with specific LPS Ag, suggesting that Ag binding is involved in the bactericidal mechanism. Live/dead cell staining and electron microscopic observations indicate that the bactericidal effect was due to disruption of the cell wall and suggest inhibition of cell division. In addition to te-hS20, the Fab and scFv were also protective in vivo, as leukopenic mice had prolonged and improved survival after administration of these Ab fragments followed by challenge with P. aeruginosa O6ad cells at 80-90% lethal dose, supporting a bactericidal mechanism independent of phagocytes and complement. Understanding of the bactericidal mechanism will allow assessment of the potential for therapeutic application of these Abs.

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.