Oxidoreductase activities of polyclonal IgGs from the sera of Wistar rats are better activated by combinations of different metal ions

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 (k_cat = 40.7 min^-1), but it increases during 60 days of spontaneous development of EAE 57.4-fold (k_cat = 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 (k_cat = 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 (k_cat = 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.

Antibodies-Abzymes with Antioxidant Activities in Two Th and 2D2 Experimental Autoimmune Encephalomyelitis Mice during the Development of EAE Pathology

The exact mechanisms of multiple sclerosis development are still unknown. However, the development of EAE (experimental autoimmune encephalomyelitis) in Th and 2D2 mice is associated with the infringement of the differentiation profiles of bone marrow hematopoietic stem cells which are bound with the production of compounds that are harmful for human autoantibodies-abzymes that hydrolyze myelin oligodendrocyte glycoprotein, myelin basic protein, and DNA. It showed that autoimmune patients' antioxidant IgG antibodies oxidise some compounds due to their peroxidase (H2O2-dependent) and oxidoreductase (H2O2-independent) activities more effectively than those in healthy humans can. It was interesting to identify whether the redox activities of the antibodies change during the development of autoimmune diseases. Here, we analyzed the change in these redox activities of the IgGs from the blood of Th and 2D2 mice, which corresponded to different stages of the EAE development. The peroxidase activity in the oxidation of ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) in the Th (4-fold) and 2D2 (2-fold) mice IgGs, on average, is higher than the oxidoreductase activity is. The peroxidase activity of the Th (1.9-fold) and 2D2 (3.5-fold) mice IgGs remarkably increased during the 40 days of the spontaneous development of EAE. Forty days after the immunization of the MOG peroxidase activity, the IgGs of the Th and 2D2 mice increased 5.6-6.0 times when they were compared with those that presented no increase (3 months of age). The mice IgGs were oxidized with 3,3'-diaminobenzidine (2.4-4.3-fold) and o-phenylenediamine (139-143-fold) less efficiently than they were with ABTS. However, the temper of the change in the IgG activity in the oxidation of these substrates during the spontaneous and MOG-induced development of EAE was close to that which occurred for ABTS. All of the data show that the IgG peroxidase and oxidoreductase activities of EAE mice can play an important role in their protection from toxic compounds and oxidative stress.

Essential Protective Role of Catalytically Active Antibodies (Abzymes) with Redox Antioxidant Functions in Animals and Humans

During the life of aerobic organisms, the oxygen resulting from numerous reactions is converted into reactive oxygen species (ROS). Many ROS are dangerous due to their high reactivity; they are strong oxidants, and react with various cell components, leading to their damage. To protect against ROS overproduction, enzymatic and non-enzymatic systems are evolved in aerobic cells. Several known non-enzymatic antioxidants have a relatively low specific antioxidant activity. Superoxide dismutases, catalase, glutathione peroxidase, glutathione S-transferase, thioredoxin, and the peroxiredoxin families are the most important enzyme antioxidants. Artificial antibodies catalyzing redox reactions using different approaches have been created. During the past several decades, it has been shown that the blood and various biological fluids of humans and animals contain natural antibodies that catalyze different redox reactions, such as classical enzymes. This review, for the first time, summarizes data on existing non-enzymatic antioxidants, canonical enzymes, and artificial or natural antibodies (abzymes) with redox functions. Comparing abzymes with superoxide dismutase, catalase, peroxide-dependent peroxidase, and H₂O₂-independent oxidoreductase activities with the same activities as classical enzymes was carried out. The features of abzymes with the redox activities are described, including their exceptional diversity in the optimal pH values, dependency and independence on various metal ions, and the reaction rate constants for healthy donors and patients with different autoimmune diseases. The entire body of evidence indicates that abzymes with redox antioxidant activities existing in the blood for a long time compared to enzymes are an essential part of the protection system of humans and animals from oxidative stress.

Comparison of the Content of Several Elements in Seawater, Sea Cucumber Eupentacta fraudatrix and Its High-Molecular-Mass Multiprotein Complex

Metal ions and other elements play many different critical roles in all biological processes. They can be especially important in high concentrations for the functioning of organisms living in seawater. It is important to understand how much the concentrations of different trace elements in such organisms can be higher than in seawater. Some marine organisms capable of rapid recovery after different injuries are fascinating in this regard. Sea cucumbers Eupentacta fraudatrix can completely restore all organs and the whole body within several weeks after their division into two parts. Here, for the first time, a comparison of the content of different elements in seawater, sea cucumber, and its very stable multiprotein complex (2000 kDa) was performed using two-jet plasma atomic emission spectrometry. Among the 18 elements we found in sea cucumbers, seawater contained only six elements in detectable amounts, and their content decreased in the following order: Mg > Ca > B > Sr ≈ Si > Cr (0.13−930 µg/g of seawater). The content of these elements in sea cucumbers was higher compared with seawater (-fold): Ca (714) > Sr (459) > Cr (75) > Si (42)> B (12) > Mg (6.9). Only four of them had a higher concentration in the protein complex than in seawater (-fold): Si (120.0) > Cr (31.5) > Ca (9.1) > Sr (8.8). The contents of Mg and B were lower in the protein complex than in seawater. The content of elements additionally found in sea cucumbers decreased in the order (µg/g of powder) of P (1100) > Fe (47) > Mn (26) > Ba (15) > Zn (13) > Al (9.3) > Mo (2.8) > Cu (1.4) > Cd (0.3), and in the protein complex, in the order of P (290) > Zn (51) > Fe (23) > Al (14) ≈ Ni (13) > Cu (7.5) > Ba (2.5) ≈ Co (2.0) ≈ Mn (1.6) > Cd (0.7) >Ag (0.2). Thus, sea cucumbers accumulate various elements, including those contained in very low concentrations in seawater. The possible biological roles of these elements are discussed here.

Increase in Autoantibodies-Abzymes with Peroxidase and Oxidoreductase Activities in Experimental Autoimmune Encephalomyelitis Mice during the Development of EAE Pathology

The exact mechanisms of multiple sclerosis (MS) development are still unknown, but the development of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice is associated with the violation of bone marrow hematopoietic stem cells (HSCs) differentiation profiles associated with the production of harmful for human’s autoantibodies hydrolyzing myelin basic protein, myelin oligodendrocyte glycoprotein (MOG_35–55), and DNA. It was shown that IgGs from the sera of healthy humans and autoimmune patients oxidize many different compounds due to their H₂O₂-dependent peroxidase and oxidoreductase activity in the absence of H₂O₂. Here we first analyzed the change in the relative redox activities of IgGs antibodies from the blood of C57BL/6 mice over time at different stages of the EAE development. It was shown that the peroxidase activity of mice IgGs in the oxidation of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) is on average 6.9-fold higher than the oxidoreductase activity. The peroxidase activity of IgGs increased during the spontaneous development of EAE during 40 days, 1.4-fold. After EAE development acceleration due to mice immunization with MOG_35–55 (5.3-fold), complexes of bovine DNA with methylated bovine serum albumin (DNA-metBSA; 3.5-fold), or with histones (2.6-fold), the activity was increased much faster. The increase in peroxidase activity after mice immunization with MOG_35–55 and DNA-metBSA up to 40 days of experiments was relatively gradual, while for DNA-histones complex was observed its sharp increase at the acute phase of EAE (14–20 days). All data show that IgGs’ redox activities can play an important role in the protection of mice from toxic compounds and oxidative stress.

IgG-Dependent Dismutation of Superoxide in Patients with Different Types of Multiple Sclerosis and Healthy Subjects

This work is the first to demonstrate that class G immunoglobulins (IgGs) in patients with multiple sclerosis and healthy individuals have the ability to catalyze the dismutation reaction of the superoxide anion radical. Thus, superoxide dismutase (SOD) activity is an intrinsic property of antibodies, which is confirmed by a number of stringent criteria. SOD activity of IgGs in patients with multiple sclerosis statistically significantly exceeds such activity in healthy individuals by 2-4 times. Moreover, the maximum activity has been registered in patients with relapsing remitting multiple sclerosis. The kinetic characteristics of the SOD reaction of IgGs are several orders of magnitude lower than those for the SOD enzyme but do not differ between patients with multiple sclerosis and healthy individuals. Consequently, abzymes with SOD activity have a lower catalysis rate than that of the enzymes and form a stronger complex with the substrates. Inhibitory analysis showed that this activity is inhibited by classical metal-dependent SOD inhibitors. The activity of IgGs was inhibited by classical metal-dependent inhibitors EDTA and TETA (triethylenetetramine). Also, high catalase activity of IgGs was detected in these patients. We suggest that these abzymes help protect the body from oxidative stress.

Comparison of Trace Elements in High-Molecular-Mass Multiprotein Complex and in Female Milk from Which It Was Obtained

Background

Many biological processes are performed by different protein complexes. During the association of proteins and enzymes forming specific complexes, the latter can include ions of various metal ions, which may be important for their formation and biological function.

Objective of the Studies

However, to date in the literature there are no data on metal ions that are part of any protein complexes.

Methods

A very stable multiprotein complex (~1000±100 kDa) was separated from other proteins of nine samples of female milk by gel filtration on Sepharose 4B. The content of microelements in the stable multiprotein complex and milk was analyzed using two-jet plasma atomic emission spectrometry.

Results

The content of different elements in milk on average decreased in the order: Ca>P>Mg>Al≥Zn≥Fe>Cu >B (0.76–3500 μg/g of dry milk powder), while the content of some elements was very low (Sr>Mn>Cr>Ba>Pb>Ag>Ni>Cd, <0.03–0.5 μg/g). The content of eight elements in stable multiprotein complex was 1.2-9.6-fold higher than in milk and increased in the order: Ca≈Mg<P<Al<Fe<Pb<Ba<Cr<Cd<Zn, while content of SPC eight metals was 12.3-110-fold higher: Cu (12.3)>B (19.7)>Ag (28.7)>Ni (38)≥Sr (110).

Conclusions

The analysis of the relative content of sixteen elements in human milk and oligomeric complexes of proteins was performed for the first time. Data on the content of metals indicate that during the formation of protein which associates the increase in the content of metal ions bound with proteins of the complex can occur. Such metal ions can be important for the formation and biological function of protein complexes.

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.

Twenty Element Concentrations in Human Organs Determined by Two-Jet Plasma Atomic Emission Spectrometry

In this paper, we have performed determination of the concentration of twenty elements in seven human organs (spleen, liver, kidney, muscle, heart, lungs, and brain) using two-jet plasma atomic emission spectrometry. The method allows multielemental analysis of solid samples without wet acid digestion. Before analysis, all human organs were first dried, ground to powders, and carbonized. The relative content of elements in each of the seven organs was very different depending on the donor. The average content of twenty elements in various organs varied in the following ranges (μg/g of dry weight): Ag (<0.02–0.2), Al (2.1–263), B (<0.5–2.5), Ca (323–1650), Cd (<0.1–114), Co (<0.2–1.0), Cr (<0.5–4.0), Cu (4.2–47), Fe (156–2900), Mg (603–1305), Mn (0.47–8.5), Mo (<0.2–4.9), Ni (<0.3–3.1), Pb (<0.3–1.9), Si (31.6–2390), Sn (<0.3–3.2), Sr (0.2–1.0), Ti (<2–31, mainly in lungs), and Zn (120–292). The concentration range of Ba in organs of five donors was <0.2–6.9 and 2.0–5600 for one donor with pneumoconiosis (baritosis). The maximum element contents were found, respectively, in the following organs: Al, B, Cr, Ni, Si, Sn, Sr, Ti (lungs), Fe (lungs and spleen), Mn (liver and kidney), Ag and Mo (liver), Ca (lungs and kidney), Cu (brain), Cd (kidney), Pb (brain), and Zn (liver, kidney, and muscle). The minimal content of elements was observed, respectively, in the following organs: Ag (all organs except liver), Ba (spleen, muscles, and brain), Ca and Mg (liver), Si (liver, muscle, and brain), Cd and Sr (heart and brain), Al, Cu, Fe, and Mn (muscle), and Zn (spleen and brain). The analysis of possible biological role and reasons for the increased content of some elements in the organs analyzed was carried out.

Substrate specificity of IgGs with peroxidase and oxidoreductase activities from sera of patients with systemic lupus erythematosus and multiple sclerosis

The analysis of IgGs to protect humans from oxidative stress through oxidation of harmful compounds was carried out. We have compared here for the first time peroxidase (in the presence of H₂ O₂ ) and oxidoreductase (in the absence of H₂ O₂ ) activities of IgGs from sera of healthy humans and patients with systemic lupus erythematosus (SLE) and multiple sclerosis (MS). In addition, substrate specificity of SLE and MS IgG preparations in the oxidation of different compounds was analyzed: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 3,3'-diaminobenzidine (DAB), homovanillic acid (HVA), o-phenylenediamine (OPD), α-naphthol, 3-amino-9-ethylcarbazole (AEC), p-hydroquinone (pHQ), and adrenaline. IgGs of healthy humans and SLE and MS patients oxidized DAB, ABTS, and OPD due to their peroxidase and oxidoreductase activities, while other compounds were substrates of IgGs only in the presence of H₂ O₂ : adrenaline was not oxidized by both activities of IgGs. The average SLE IgGs peroxidase activity increased statistically significant in comparison with abzymes from healthy humans in the order (-fold): OPD (1.2) <  DAB (1.7) < α-naphtol (2.2) ≤ AEC (2.4) < ABTS (4.5) < 5-ASA (10.6), while with oxidoreductase activity: OPD (1.8) ≤ DAB (2.1-fold) < ABTS (5.0). Only HVA was oxidized by IgGs with peroxidase activity of healthy donors faster than by SLE (1.3-fold) and MS abzymes (2.4-fold). In the oxidation of several substrates, only three IgGs of MS patients were used. The data speak of a tendency to increase the peroxidase and oxidoreductase activities of MS IgGs in comparison with healthy donors, but to a lesser extent: OPD (1.1 to 1.2-fold) ≤ ABTS (1.2 to 1.8-fold). It was shown that development of SLE and MS leads to increase in peroxidase and oxidoreductase activities of IgGs toward most of classical substrates. Thus, abzymes can serve as an additional factor of reactive oxygen species detoxification protecting of patients with SLE and MS from some harmful compounds somewhat better than healthy peoples.

Cow Milk Lactoferrin Possesses Several Catalytic Activities

Lactoferrin (LF) is a Fe³⁺-binding glycoprotein, that was first recognized in milk and then in other epithelial secretions and barrier body fluids to which many different functions have been attributed to LF including protection from iron-induced lipid peroxidation, immunomodulation, cell growth regulation, DNA and RNA binding, as well as transcriptional activation, еtс. The polyfunctional physiological role of LF is still unclear, but it has been suggested to be responsible for primary defense against microbial and viral infections. It was shown previously that human milk LF possesses several enzymatic activities: DNase, RNase, ATPase, phosphatase, and amylase. Analysis of human, cow, horse, buffalo and camel LF showed a highly conserved three-dimensional (3D) structure including only detail differences in the species. Recently, it was shown that similar to human cow LF possesses DNase and RNase activities. Using different methods here we have shown for the first time that LFs from the milk of seven cows of different breeds possess high peroxidase, protease, amylase, protease, and phosphatase activities. Protease activity of cow LFs was activated by Mg²⁺ and Ca²⁺ ions. In contrast to human LFs, ATPase activity was revealed only in three of seven cow LF preparations. The discovery that LF possesses these activities may contribute to understanding the multiple physiological functions of this extremely polyfunctional protein including its protective role against microbial and viral infections.

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.

Substrate specificity of healthy human sera IgG antibodies with peroxidase and oxydoreductase activities

We have carried out an analysis of whether blood IgG antibodies can protect humans from oxidative stress by oxidizing different harmful compounds. A somewhat unexpected result was obtained. We show here for the first time that healthy human sera IgGs with the peroxidase (in the presence H2O2) efficiently oxidize different compounds: 3,3'-diaminobenzidine (1; DAB), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (2; ATBS), o-phenylenediamine (3; OPD), homovanillic acid (4; HVA), α-naphthol (5), 5-aminosalicylic acid (6; 5-ASA) and 3-amino-9-ethylcarbazole (7; AEC), but seven of nine IgG preparations from different volunteers cannot oxidize p-hydroquinone (8: pHQ). The average apparent kcat values in the H2O2-dependent oxidation by human IgGs decreased in the following order (min-1): ATBS (73.7) ≥ DAB (66.3) > AEC (38.0) ≥ HVA (19.8) ≥ α-naphthol (8.6) > OPD (0.62) ≥ 5-ASA (0.48) > pHQ (0.24). In the absence of H2O2 (oxidoreductase activity), the relative average kcat values decreased in the following order (min-1): DAB (52.1) ≥ ATBS (50.5) > OPD (0.25). The peroxidase average activity of human IgGs was higher than the oxidoreductase one: 1.2-, 1.5- and 2.5-fold for DAB, ATBS and OPD, respectively. It should be assumed that antibodies can oxidize in addition to the large number of other different compounds analysed by us. As a whole, the specific wide repertoire of polyclonal human IgGs oxidizing various compounds could play an important role in protecting humans from oxidative stress and serve as an additional natural system destroying H2O2 and different toxic mutagenic and carcinogenic compounds.

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.

Antibodies from the sera of HIV-infected patients efficiently hydrolyze all human histones

Histones and their post-translational modifications have key roles in chromatin remodeling and gene transcription. Besides intranuclear functions, histones act as damage-associated molecular pattern molecules when they are released into the extracellular space. Administration of exogenous histones to animals leads to systemic inflammatory and toxic responses through activating Toll-like receptors and inflammasome pathways. Here, using ELISA it was shown that sera of HIV-infected patients and healthy donors contain autoantibodies against histones. Autoantibodies with enzymic activities (abzymes) are a distinctive feature of autoimmune diseases. It was interesting whether antibodies from sera of HIV-infected patients can hydrolyze human histones. Electrophoretically and immunologically homogeneous IgGs were isolated from sera of HIV-infected patients by chromatography on several affinity sorbents. We present first evidence showing that 100% of IgGs purified from the sera of 32 HIV-infected patients efficiently hydrolyze from one to five human histones. Several rigid criteria have been applied to show that the histone-hydrolyzing activity is an intrinsic property of IgGs of HIV-infected patients. The relative efficiency of hydrolysis of histones (H1, H2a, H2b, H3, and H4) significantly varied for IgGs of different patients. IgGs from the sera of 40% of healthy donors also hydrolyze histones but with an average efficiency approximately 16-fold lower than that of HIV-infected patients. Similar to proteolytic abzymes from the sera of patients with several autoimmune diseases, histone-hydrolyzing IgGs from HIV-infected patients were inhibited by specific inhibitors of serine and of metal-dependent proteases, but an unexpected significant inhibition of the activity by specific inhibitor of thiol-like proteases was also observed. Because IgGs can efficiently hydrolyze histones, a negative role of abzymes in development of acquired immune deficiency syndrome cannot be excluded. Copyright © 2016 John Wiley & Sons, Ltd.

Systemic lupus erythematosus: molecular cloning and analysis of recombinant monoclonal kappa light chain NGTA2-Me-pro-ChTr possessing two different activities-trypsin-like and metalloprotease

Polyclonal antibodies hydrolyzing myelin basic protein (MBP) can play an important role in the pathogenesis of multiple sclerosis and systemic lupus erythematosus (SLE). An immunoglobulin light chain phagemid library derived from peripheral blood lymphocytes of patients with SLE was used. The small pools of phage particles displaying light chains with different affinity for MBP were isolated by affinity chromatography on MBP-Sepharose. The fraction eluted with 0.5M NaCl was used for preparation of individual monoclonal light chains (MLChs, 26-27kDa). The clones were expressed in Escherichia coli in a soluble form; MLChs were purified by metal-chelating chromatography followed by gel filtration. In mammalians, there are serine proteases and metalloproteases. These and many other enzymes usually have only one active site and catalyze only one chemical reaction. In contrast to canonical proteases, one MLCh (NGTA2-Me-pro-ChTr) efficiently hydrolyzed MBP (but not other proteins) and four different oligopeptides corresponding to four immunodominant sequences containing cleavage sites of MBP. The proteolytic activity of MLCh was efficiently inhibited only by specific inhibitors of serine-like (phenylmethanesulfonylfluoride, PMSF) and metalloproteases (EDTA). It was shown that MLCh possess independent serine-like and metal-dependent activities. The principal existence of monoclonal antibodies with two different proteolytic activities is unexpected but very important for the further understanding of at present unknown biological functions of human antibodies.

IgG abzymes with peroxidase and oxidoreductase activities from the sera of healthy humans

We present the evidence showing that small fractions of electrophoretically homogeneous immunoglobulin G (IgGs) from the sera of healthy humans and their Fab and F(ab)2 fragments oxidize 3,3'-diaminobenzidine through a peroxidase activity in the presence of H2 O2 and through an oxidoreductase activity in the absence of H2 O2 . During purification on protein G-Sepharose and gel filtration, the polyclonal IgGs partially lose the Me(2+) ions. After extensive dialysis of purified Abs against agents chelating metal ions, the relative peroxidase activity decreased dependently of IgG analyzed from 100 to ~10-85%, while oxidoreductase activity from 100 to 14-83%. Addition of external metal ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. Chromatography of the IgGs on Chelex non-charged with Cu(2+) ions results in the adsorption of a small IgG fraction bound with metal ions (~5%), while Chelex charged with Cu(2+) ions bind additionally ~38% of the total IgGs. Separation of Abs on both sorbents results in IgG separation to many different subfractions demonstrating various affinities to the chelating resin and different levels of the specific oxidoreductase and peroxidase activities. In the presence of external Cu(2+) ions, the specific peroxidase activity of several IgG subfractions achieves 20-27 % as compared with horseradish peroxidase (HRP, taken for 100%). The oxidoreductase activity of these fractions is ~4-6-fold higher than that for HRP. Antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases are known to represent critical defence mechanisms for preventing oxidative modifications of DNA, proteins, and lipids. Peroxidase and oxidoreductase activities of human IgGs could also play an important role in the protection of organisms from oxidative stress and toxic compounds.

Effect of CoCl(2) treatment on major and trace elements metabolism and protein concentration in mice

Cobalt (Co) is a transition metal and an essential trace element, required for vitamin B(12) biosynthesis, enzyme activation and other biological processes, but toxic in high concentrations. There is lack of data for the effect of long-term Co(II) treatment on the concentrations of other trace elements. We estimate the influence of cobalt chloride (CoCl(2)) on the relative content of different metals in mouse plasma using two-jet arc plasmatron atomic emission and on the total protein content. On average, the content of different elements in the plasma of 2-month-old balb/c mice (control group) decreased in the order: Ca>Mg>Si>Fe>Zn>Cu≥Al≥B. The treatment of mice for 60 days with CoCl(2) (daily dose 125 mg/kg) did not appreciably change the relative content of Ca, Cu, and Zn, while a 2.4-fold statistically significant decrease in the content of B and significant increase in the content of Mg (1.4-fold), Al and Fe (2.0-fold) and Si (3.2-fold) was found. A detectable amount of Mo was observed only for two control mice, while the plasma of 9 out of 16 mice of the treated group contained this metal. The administration of Co made its concentration detectable in the plasma of all mice of the treated group, but the relative content varied significantly. The treatment led to a 2.2-fold decrease in the concentration of the total plasma protein. Chronic exposure to CoCl(2) affects homeostasis as well as the concentrations and metabolism of other essential elements, probably due to competition of Co ions for similar binding sites within cells, altered signal transduction and protein biosynthesis. Long-term treatment also leads to significant weight changes and reduces the total protein concentration. The data may be useful for an understanding of Co toxicity, its effect on the concentration of other metal ions and different physiological processes.

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.

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.

Metal dependent hydrolysis of β-casein by sIgA antibodies from human milk

We present the first evidence that electrophoretically and immunologically homogeneous sIgAs purified from milk of healthy human mothers by chromatography on Protein A-Sepharose and FPLC gel filtration contain intrinsically bound metal ions (Ca  >  Mg ≥ Al > Fe approximately  Zn ≥ Ni ≥ Cu ≥ Mn), the removal of which by a dialysis against ethylenediamine tetraacetic acid (EDTA) leads to a significant decrease in the β-casein-hydrolyzing activity of these antibodies (Abs). An affinity chromatography of total sIgAs on benzamidine-Sepharose interacting with canonical serine proteases separates a small metalloprotease sIgA fraction (6.8 ± 2.4%) from the main part of these Abs with a serine protease-like β-casein-hydrolyzing activity. The relative activity of this metalloprotease sIgA fraction containing intrinsically bound metal ions increases ∼1.2-1.9-fold after addition of external metal ions (Mg(2+) > Fe(2+) > Cu(2+) ≥ Ca(2+) ≥ Mn(2+)) but decreases by 85 ± 7% after the removal of the intrinsically bound metals. The metalloprotease sIgA fraction free of intrinsic metal ions demonstrates a high β-casein-hydrolyzing activity in the presence of individual external metal ions (Fe(2+) > Ca(2+) > Co(2+) ≥ Ni(2+)) and especially several combinations of metals: Co(2+) + Ca(2+) < Mg(2+) + Ca(2+) < Ca(2+) + Zn(2+) < Fe(2+) + Zn(2+) < Fe(2+) + Co(2+) < Fe(2+) + Ca(2+). The patterns of hydrolysis of a 22-mer oligopeptide corresponding to one of sIgA-dependent specific cleavage sites in β-casein depend significantly on the metal used. Metal-dependent sIgAs demonstrate an extreme diversity in their affinity for casein-Sepharose and chelating Sepharose, and interact with Sepharoses bearing immobilized monoclonal mouse IgGs against λ- and κ-type light chains of human Abs. Possible ways of the production of metalloprotease abzymes (Abz) by human immune system are discussed.

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.