Evolution of catalytic centers of antibodies by virtual screening of broad repertoire of mutants using supercomputer

It is proposed to perform quantum mechanical/molecular dynamics calculations of chemical reactions that are planned to be catalyzed by antibodies and then conduct a virtual screening of the library of potential antibody mutants to select an optimal biocatalyst. We tested the effectiveness of this approach by the example of hydrolysis of organophosphorus toxicant paraoxon using kinetic approaches and X-ray analysis of the antibody biocatalyst designed de novo.

Genetic Engineering of Native Chain Combinations of B-Cell Repertoires on the Surface of Methylotrophic Yeasts Pichia pastoris

We designed genetic constructs for exposing Fab-fragment library of natively paired single cell B-cell receptors on the surface of Pichia pastoris yeast cells. We have previously obtained the A17 antibody in our laboratory [6]. In this study we showed that the newly designed genetic constructs provide a compatible level of A17 antibody Fab fragment on the surface of yeast cells as well as in the case of vectors containing DNA fragments corresponding to each chain of the antibody. The data suggest that the developed approach for constructing immunoglobulin gene libraries is adequate and fully convenient for studying properties of the real human B-lymphocyte repertoire.

Preparation of Recombinant Serpin from Red King Crab Paralithodes сamtschaticus for Biomedical Research Purposes

Genetic constructs with different leader sequences for intra- and extracellular expression of the target protein were generated and an original method for effective selection of clones with maximum expression was developed. For intracellular expression in the Pichia pastoris system, seprin content in cells was 6 mg/liter.

Design of Chemical Conjugate for Targeted Therapy of Multiple Sclerosis Based of Constant Fragment of Human Antibody Heavy Chain and Peptoid Analog of Autoantigen MOG35-55

Elimination of B cells producing autoantibodies to neuroantigens is considered as beneficial in the treatment of multiple sclerosis. Myelin oligodendrocyte glycoprotein (MOG) is a significant autoantigen in multiple sclerosis. It was shown that MOG-like peptoid AMogP3 can bind autoantibodies produced by pathological lymphocytes. We propose a structure of an innovative drug for targeted elimination of the pool of autoreactive B cells responsible for multiple sclerosis pathogenesis; this compound is a complex of peptoid AMogP3 with Fc fragment of human immunoglobulin. The obtained Fc-PEG-AMogP3 conjugate effectively interact with autoreactive antibodies, which attests to their high therapeutic potential.

[Expression Of DNA-Encoded Antidote to Organophosphorus Toxins in the Methylotrophic Yeast Pichia Pastoris]

A platform for the cloning and expression of active human butyrylcholinesterase (BuChE) in the yeast Pichia pastoris is first presented. Genetic constructs for BuChE gene expression, separately and in conjunction with a proline-rich peptide called proline-rich attachment domain (PRAD), are based on the vector pPICZαA. It is shown that the highest level of production is achieved in the expression of a BuChE gene without PRAD pPICZαA. It is found that one can obtain up to 125 mg of active enzyme from 1 L of culture medium at an optimal pH environment (pH 7.6), an optical seed culture density of 3 o.u., and an optimum methanol addition mode of (0.5% methanol in the first day and 0.2% thereafter from the second day).

Chemical Polysialylation and In Vivo Tetramerization Improve Pharmacokinetic Characteristics of Recombinant Human Butyrylcholinesterase-Based Bioscavengers

Organophosphate toxins (OPs) are the most toxic low-molecular compounds. The extremely potent toxicity of OPs is determined by their specificity toward the nerve system. Human butyrylcholinesterase (hBChE) is a natural bioscavenger against a broad spectrum of OPs, which makes it a promising candidate for the development of DNA-encoded bioscavengers. The high values of the protective index observed for recombinant hBChE (rhBChE) make it appropriate for therapy against OP poisoning, especially in the case of highly toxic warfare nerve agents. Nevertheless, large-scale application of biopharmaceuticals based on hBChE is restricted due to its high cost and extremely rapid elimination from the bloodstream. In the present study, we examine two approaches for long-acting rhBChE production: I) chemical polysialylation and II) in-vivo tetramerization. We demonstrate that both approaches significantly improve the pharmacokinetic characteristics of rhBChE (more than 5 and 10 times, respectively), which makes it possible to use rhBChE conjugated with polysialic acids (rhBChE-CAO) and tetrameric rhBChE (4rhBChE) in the treatment of OP poisonings.

Specific Depletion of Myelin-Reactive B Cells via BCR-Targeting

B cells play a crucial role in the development and pathogenesis of systemic and organ-specific autoimmune diseases. Autoreactive B cells not only produce antibodies, but also secrete pro-inflammatory cytokines and present specific autoantigens to T cells. The treatment of autoimmune diseases via the elimination of the majority of B cells using the monoclonal anti-CD19/20 antibody (Rituximab) causes systemic side effects and, thus, requires a major revision. Therapeutic intervention directed towards selective elimination of pathogenic autoreactive B cells has the potential to become a universal approach to the treatment of various autoimmune abnormalities. Here, we developed a recombinant immunotoxin based on the immunodominant peptide of the myelin basic protein (MBP), fused to the antibody Fc domain. We showed that the obtained immunotoxin provides selective in vivo elimination of autoreactive B cells in mice with experimental autoimmune encephalomyelitis. The proposed conception may be further used for the development of new therapeutics for a targeted treatment of multiple sclerosis and other autoimmune disorders.

Chemical Polysialylation and In Vivo Tetramerization Improve Pharmacokinetic Characteristics of Recombinant Human Butyrylcholinesterase-Based Bioscavengers

Organophosphate toxins (OPs) are the most toxic low-molecular compounds. The extremely potent toxicity of OPs is determined by their specificity toward the nerve system. Human butyrylcholinesterase (hBChE) is a natural bioscavenger against a broad spectrum of OPs, which makes it a promising candidate for the development of DNA-encoded bioscavengers. The high values of the protective index observed for recombinant hBChE (rhBChE) make it appropriate for therapy against OP poisoning, especially in the case of highly toxic warfare nerve agents. Nevertheless, large-scale application of biopharmaceuticals based on hBChE is restricted due to its high cost and extremely rapid elimination from the bloodstream. In the present study, we examine two approaches for long-acting rhBChE production: I) chemical polysialylation and II) in-vivo tetramerization. We demonstrate that both approaches significantly improve the pharmacokinetic characteristics of rhBChE (more than 5 and 10 times, respectively), which makes it possible to use rhBChE conjugated with polysialic acids (rhBChE-CAO) and tetrameric rhBChE (4rhBChE) in the treatment of OP poisonings.

Excessive Labeling Technique Provides a Highly Sensitive Fluorescent Probe for Real-time Monitoring of Biodegradation of Biopolymer Pharmaceuticals in vivo

Recombinant proteins represent a large sector of the biopharma market. Determination of the main elimination pathways raises the opportunities to significantly increase their half-lives in vivo. However, evaluation of biodegradation of pharmaceutical biopolymers performed in the course of pre-clinical studies is frequently complicated. Noninvasive pharmacokinetic and biodistribution studies in living organism are possible using proteins conjugated with near-infrared dyes. In the present study we designed a highly efficient probe based on fluorescent dye self-quenching for monitoring of in vivo biodegradation of recombinant human butyrylcholinesterase. The maximum enhancement of integral fluorescence in response to degradation of an intravenously administered enzyme was observed 6 h after injection. Importantly, excessive butyrylcholinesterase labeling with fluorescent dye results in significant changes in the pharmacokinetic properties of the obtained conjugate. This fact must be taken into consideration during future pharmacokinetic studies using in vivo bioimaging.

Excessive Labeling Technique Provides a Highly Sensitive Fluorescent Probe for Real-time Monitoring of Biodegradation of Biopolymer Pharmaceuticals in vivo

Recombinant proteins represent a large sector of the biopharma market. Determination of the main elimination pathways raises the opportunities to significantly increase their half-lives in vivo. However, evaluation of biodegradation of pharmaceutical biopolymers performed in the course of pre-clinical studies is frequently complicated. Noninvasive pharmacokinetic and biodistribution studies in living organism are possible using proteins conjugated with near-infrared dyes. In the present study we designed a highly efficient probe based on fluorescent dye self-quenching for monitoring of in vivo biodegradation of recombinant human butyrylcholinesterase. The maximum enhancement of integral fluorescence in response to degradation of an intravenously administered enzyme was observed 6 h after injection. Importantly, excessive butyrylcholinesterase labeling with fluorescent dye results in significant changes in the pharmacokinetic properties of the obtained conjugate. This fact must be taken into consideration during future pharmacokinetic studies using in vivo bioimaging.

Polyreactive Monoclonal Autoantibodies in Multiple Sclerosis: Functional Selection from Phage Display Library and Characterization by Deep Sequencing Analysis

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that primarily affects young and middle-aged people. It is widely accepted that B lymphocyte activation is required for MS progression. Despite the fact that the exact triggering mechanisms of MS remain enigmatic, one may suggest that MS can be induced by viral or bacterial infection in combination with specific genetic and environmental factors. Using deep sequencing and functional selection methodologies we characterized clones of poly- and cross-reactive antibodies that are capable of simultaneous recognition of viral proteins and autoantigens. The latter, in turn, possibly may trigger MS progression through molecular mimicry. It was identified that two cross-reactive antigens are probably recognized by light or heavy chains individually. According to the high structural homology between selected autoantibodies and a number of various antiviral IgGs, we suggest that a wide range of pathogens, instead of a single virus, be regarded as possible triggers of MS.

Creation of catalytic antibodies metabolizing organophosphate compounds

Development of new ways of creating catalytic antibodies possessing defined substrate specificity towards artificial substrates has important fundamental and practical aspects. Low immunogenicity combined with high stability of immunoglobulins in the blood stream makes abzymes potent remedies. A good example is the cocaine-hydrolyzing antibody that has successfully passed clinical trials. Creation of an effective antidote against organophosphate compounds, which are very toxic substances, is a very realistic goal. The most promising antidotes are based on cholinesterases. These antidotes are now expensive, and their production methods are inefficient. Recombinant antibodies are widely applied in clinics and have some advantage compared to enzymatic drugs. A new potential abzyme antidote will combine effective catalysis comparable to enzymes with high stability and the ability to switch on effector mechanisms specific for antibodies. Examples of abzymes metabolizing organophosphate substrates are discussed in this review.

Recombinant Human Butyrylcholinesterase As a New-Age Bioscavenger Drug: Development of the Expression System

Butyrylcholinesterase (BChE) is a serine hydrolase (EC 3.1.1.8) which can be found in most animal tissues. This enzyme has a broad spectrum of efficacy against organophosphorus compounds, which makes it a prime candidate for the role of stoichiometric bioscavenger. Development of a new-age DNA-encoded bioscavenger is a vival task. Several transgenic expression systems of human BChE were developed over the past 20 years; however, none of them has been shown to make economic sense or has been approved for administration to humans. In this study, a CHO-based expression system was redesigned, resulting in a significant increase in the production level of functional recombinant human butyrylcholinesterase as compared to the hitherto existing systems. The recombinant enzyme was characterized with Elman and ELISA methods.

Polyreactive monoclonal autoantibodies in multiple sclerosis: functional selection from phage display library and characterization by deep sequencing analysis

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that primarily affects young and middle-aged people. It is widely accepted that B lymphocyte activation is required for MS progression. Despite the fact that the exact triggering mechanisms of MS remain enigmatic, one may suggest that MS can be induced by viral or bacterial infection in combination with specific genetic and environmental factors. Using deep sequencing and functional selection methodologies we characterized clones of poly- and cross-reactive antibodies that are capable of simultaneous recognition of viral proteins and autoantigens. The latter, in turn, possibly may trigger MS progression through molecular mimicry. It was identified that two cross-reactive antigens are probably recognized by light or heavy chains individually. According to the high structural homology between selected autoantibodies and a number of various antiviral IgGs, we suggest that a wide range of pathogens, instead of a single virus, be regarded as possible triggers of MS.

[Therapeutic effect of encapsulated into the nanocontainers MBP immunodominant peptides on EAE development in DA rats]

Multiple Sclerosis (MS) is a serve autoimmune neurodegenerative disease. Development of innovative approaches of MS treatment is of a high priority in the modern immunology and pharmacy. In the present study we showed high therapeutic efficiency of immunodominant peptides of myelin basic protein (MBP) incorporated into the monolayer mannosylated liposomes on the development of experimental autoimmune encephalomyelitis (EAE) in DA rats. MBP is a component ofoligodendrocytes' membrane, which form axonal sheath, and is one of the major autoantigens in MS. We analyzed binding pattern ofanti-MBP autoantibodies from MS patients using previously designed MBP epitope library. Utilizing the same approach we investigated pool of anti-MBP antibodies from SJL/J and C57/BL6 mice and DA rats with induced EAE. The most relevant rodent model to MS was EAE in DA rats according to the autoantibodies' binding pattern. We selected three immunodominant MBP fragments encapsulated in monolayer mannosylated liposomes for the following treatment of verified DA rodent model. MBP fragment 46-62 was the most effective in reducing of the first EAE attack, whereas MBP 124-139 and 147-160 inhibited development of pathology during remission stage. Simultaneous administration of these peptides in liposomes significantly decreased level of anti-MBP antibodies. Synergetic therapeutic effect of MBP fragments reduced integral disease score by inhibiting first EAE wave and subsequent remission, thus, our findings disclosure novel approaches for efficient treatment of Multiple Sclerosis.

[Functional degradation of myelin basic protein. Proteomic approach]

Proteolytic degradation of autoantigens is of prime importance in current biochemistry and immunology. The most fundamental issue in this field is the functional role of peptides produced when the specificity of hydrolysis changes during the shift from health to disease and from normal state to pathology. The identification of specific peptide fragments in many cases proposes the diagnostic and prognostic criterion in the pathology progression. The aim of this work is comparative study of the degradation peculiarities of one of the main neuroantigen, myelin basic protein by proteases, activated during progress of pathological demyelinating process, and by proteasome of different origin. The comparison of specificity of different studied biocatalysts gives reason to discuss the critical change in the set of myelin basic protein fragments capable to be presented by major histocompatibility complex class I during neurodegeneration, which can promote the progress of autoimmune pathological process.

[Expression of the catalytic antibodies in eukaryotic systems]

Expression of recombinant antibodies in mammalian cells is one of key problems in immunobiotechnology. Alternatively, expression of a broad panel of antibodies and of their fragments may be effectively done in yeast cells. We obtained expression strains of the methylotrophic beast Pichia pastoris producing single chain human catalytic antibody A17 (A.17scFv), Fab-fragment (A.17Fab) and full-size light chain (A.17Lch). These antibodies were characterized in terms of functional activity. The capacity to specifically bind and transform organophosphorus compounds has been demonstrated for A.17scFv and A.17Fab. The loss of activity of the antibody light chain when expressed alone indicates that the active site is formed by both heavy and light chains of the antibody. We determined the reversible constant Kd and the first order constant (k2) of the reaction of the covalent modification of A.17scFv and A.17Fab by irreversible inhibitor of the serine proteases p-nitrophenyl 8-methyl-8-azobicyclo[3.2.1]phosphonate (Phosphonate X). Calculated values indicate that activity of the antibodies expressed in yeast is similar to the full-size antibody A17 and single chain antibody A.17 expressed in CHO and E. coli cells respectively.

[Diagnostic and pathogenetic implications of the site specificity of antibody proteases in multiple sclerosis]

Disseminated sclerosis is currently regarded as a CNS autoimmune disease. One of the mechanisms behind this pathology is antibody (AB) formation. In this context, recent data on AB with proteolytic activity are of importance because they participate in selective proteolysis of myelin proteins in patients with disseminated sclerosis. This paper focuses on AB-proteases associated with disseminated sclerosis and site-specificity of antibody-mediated proteolysis of myelin basic protein. Protocol of serodiagnostic algorithm to be used in clinical practice is described.

Suppression of ongoing experimental allergic encephalomyelitis in DA rats by novel peptide drug, structural part of human myelin basic protein 46-62

Previously, we demonstrated that autoantibodies (AAb) in multiple sclerosis (MS) reveal site-specific binding and cleavage toward myelin basic protein (MBP) epitope library. We have found several fragments of MBP immunodominant in terms of AAb binding. Here, we applied these peptides to DA rats with induced protracted relapsing experimental allergic encephalomyelitis (EAE) most closely related to MS. DA rats with EAE induced by syngenic spinal cord homogenate in complete Freund's adjuvant were treated by nasal route with human MBP 46-62, 81-102, 124-139, 147-170, and Copaxone. MBP 124-139 and 147-170 displayed only mild therapeutic effects but MBP 46-62 significantly reduced EAE, reflected by lower clinical scores and shorter EAE duration compared to controls.

Analysis of myelin basic protein fragmentation by proteasome

The proteasome is a high molecular protein complex whose purpose is specific protein degradation in eukaryotic cells. One of the proteasome functions is to produce peptides, which will then be presented on the outer cell membrane using main histocompatibility complex (MHC) molecules of the first or second class. There are definite reasons to believe that proteasome directly takes part in the specific degradation of myelin basic protein (MBP), which make up to 30% of all proteins in the myelin sheath of neuronal axons. The details of the proteasomal degradation of MBP are still unclear. In this work, the features of specific MBP degradation by proteasome were studied.It was demonstrated that MBP (non-ubiquitinated) is a good substrate for 20S and for the 26S proteasome. This is the first work on detecting the sites of MBP proteolysis by proteasome from brains of SJL/J/J and Balb/C mice's lines. Substantial differences in the degradation pattern of this neuroantigen were found, which could indicate the better presentation MBP parts on MHC molecules in the case of mice predisposed to the development of experimental autoimmune encephalomyelitis.

[Expression of human serum albumin in metylotrophic yeast Pichia pastoris and its structural and functional analysis]

The stable strain of methylotrophic yeast Pichia pastoris secreting human serum albumin into cultural medium was obtained. Optimal conditions for expression of the protein were determined. We characterized the recombinant protein by mass spectrometry and circular dichroism and analyzed its catalytic activity.

[Prospects for designing Russian gene engineering agents for medicine. Rastan is the first Russian recombinant human growth hormone]

The development of modern pharmacology cannot be imagined without the use of genetic engineering methods (recombinant DNA technology). The success of medicine is increasingly based on the active use of protein preparations obtained using the technology of transferring hereditary information (genes) from one organism to another. The emergence of the ability to express foreign genes in the cells of various organisms (both eukaryotes and prokaryotes) has become one of the revolutionary events in the science of the last two decades of the 20th century and laid the foundations of modern biotechnology.

[Antibody-mediated proteolysis of myelin-associated proteins as a new mechanism of control over demyelinization processes in multiple sclerosis]

Natural antibodies possessing catalytic activity present a new group of biologically active substances that are found in various autoimmune diseases such as autoimmune thyroiditis, myocarditis, multiple sclerosis, and system lupus erythematosus. Presently, an interconnection between the activity of these antibodies and the extent of organic and tissue lesion in autoaggression have been revealed. Clinical use of catalytic antibodies as a diagnostic criterion to evaluate the severity of disease, a prognostic criterion of the risk of invalidization, and as a pathogenetic basis for medicamentous treatment of autoimmune process is a promising directions of study of the role of catalytic antibodies.

[Catalytic autoantibodies--a new molecular instrument in cardiology and ophthalmology]

AIM

To develop a conceptual model of using catalytic autoantibodies as diagnostic and monitoring tools in organ-specific autoimmune disorders.

MATERIAL AND METHODS

A total of 99 patients (56 males and 43 females aged 21-52 years) with autoimmune myocarditis (AM) and 198 patients (77 males and 121 females aged 8-79 years) with autoimmune uveitis (A U) participated in the study. AM patients were examined for anticardiomyosin and anti-DNA autoantibodies (ACM, ADNAab), AU patients - for autoantibodies to S-antigen, IRBP, redopsin, phosphocine, autoDNA.

RESULTS

AM patients had double level of DNA-binding autoantibodies. In 1/3 of them there was hydrolysing DNA and cytotoxic activity. In AU patients maximal titers were in Behcet's disease, sympathic ophthalmia, generalized uveitis and viral uveitis.

CONCLUSION

Autoantibodies with different specificity and function including DNA-abzymes can be additional diagnostic and prognostic markers.

[Catalytic autoantibodies as a new molecular instrument in rheumatological practice]

AIM

To compare clinicopathogenetic value of DNA-hydrolizing autoantibodies or DNA-abzymes in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

MATERIAL AND METHODS

We studied sera from 180 patients with SLE, 180 RA patients and 128 healthy donors matched by age and gender; assessed catalytic and cytotoxic activity of DNA-abzymes in patients with different variants of SLE and RA course.

RESULTS

The highest catalytic and cytotoxic activities of DNA abzymes were observed in SLE patients. In SLE catalytic and cytotoxic activities of DNA abzymes ranged widely and their mean values depended on SLE activity in patients with systemic lesions. DNA-abzymes in RA patients showed lower catalytic and cytotoxic activities in relation to substrate DNA and target cells than in SLE. DNA-abzymes occurred most frequently in patients with high activity of RA, slow-progressive and lingering course of RA, especially in early development of visceral (extra-articular) pathology. Characteristic for DNA-abzymes in RA and SLE is the phenomenon of wide-range fluctuations due to factors determinating probability of induction of function of Ab-mediated catalysis and, therefore, incidence rates of DNA-abzymes, probably catalytic autoAb of the other specificity in a population of patients with systemic autoimmune diseases.

CONCLUSION

The data indicate the validity of DNA abzymes use in clinical practice for realization of diagnostic and therapeutic programs in SLE and RA.

[Catalytic autoantibodies in autoimmune myocarditis: clinical and pathogenetic implications]

AIM

To evaluate pathogenetic and clinical significance of autoantibodies (AAB) with catalytic activity in the serum of patients with autoimmune myocarditis (AM).

MATERIAL AND METHODS

The study was made on the sera from 99 patients with AM of different course: malignant, benign, myocardiosclerosis (MCS). In addition to standard immunological parameters, the study was made of serum levels of anticardiomyosine-antiCM (protabzymes) and anti-DNA (DNA-abzymes) of AAB. After obtaining anti-CM and anti-DNA IgG-AT, we determined non-specific and specific proteolytic activity of anti-CM.

RESULTS

Maximal specific activity of protabzymes was seen in 73% patients with malignant AM, it correlated with blood levels of anti-CM AAB, DNA-abzymes activity was very high in 45% patients. In MCS proteolytic activity of autoAT was absent in 61% patients. In benign AM occurrence of protabzymes was confirmed in 35% cases. Elevated DNA-hydrolyzing activity of DNA-abzymes occurred in 13% cases. The activity had no significant correlation with serum titers of AB. In MCS proteolytic activity of AAB was absent in 61% cases, but high activity of anti-CM AAB was in 28%. The activity of DNA-abzymes in 44% ranged considerably which, in seropositive cases, detected significant correlation with serum titers of DNA-binding autoAT.

CONCLUSION

Evaluation of catalytic activity of AAB may be considered as a criterial test assessing the stage, clinical variants and severity of AM. It also permits formulation of the disease prognosis and its possible outcomes.

[DNA-abzymes in rheumatoid arthritis: pathogenetic and clinical significance]

AIM

To study possible pathogenetic role and clinical significance of DNA-hydrolysing autoantibodies (autoAB) or DNA-abzymes in patients with rheumatoid arthritis.

MATERIAL AND METHODS

Prevalence of DNA-abzymes and their catalytic activity were studied in 400 patients with rheumatoid arthritis (RA) and 88 healthy donors matched by age and gender.

RESULTS

Associated with DNA-binding autoAB DNA-hydrolysing activity was detected in 41.5% cases of RA. DNA-abzymes were maximally active in men with rheumatoid factor (RF) and women without RF, while it was minimal in men without RF and women with RF. By catalytic activity there was no significant differences between patients with RF and without it. The highest catalytic activity of DNA abzymes was detected in patients with distinct extraarticular pathology. DNA-abzymes were also active in patients with x-ray stage III-IV of the disease in association with high prevalence of catalytic autoAB. DNA abzymes were also active in patients with RA activity stage II and III.

CONCLUSION

It is possible to use DNA-abzymes in clinical practice for monitoring of the disease activity in RA.

[Achievements and prospects of clinical abzymology]

Catalytic autoantibodies (abzymes) are autoantibodies that are potentially ready to realize certain effects in the organism, first of all antibody-mediated catalysis and cytotoxicity. Natural abzymes with protolytic (protabzymes) and DNA-hydrolyzing DNA-abzymes) activity are of the greatest interest. The most impressive example of the catalytic activity of protabzymes is hydrolysis of specific proteins, revealed in patients with autoimmune diseases, such as bronchial asthma (vasoactive intestinal neuropeptide), autoimmune thyroiditis (thyroglobulin), multiple sclerosis (myelin basic protein), and autoimmune myocarditis (cardiomyosin). The pathogenic role of DNA-abzymes is not quite clear yet. However, it has been proven that they present a powerful regulator of apoptosis and other cytotoxicity mechanisms in systemic autoimmune diseases and tumors. The most promising is use of abzymes as illness activity markers, and as therapeutic agents capable of catalyzing specific proteins or activating antitumoral chemotherapeutic preparations.

Catalytic autoantibodies in multiple sclerosis: Pathogenetic and clinical aspects

The significance of catalytic autoantibodies abzymes in the pathogenesis of multiple sclerosis was evaluated in patients with different disease patterns and severity of disability.

Antibody proteases: induction of catalytic response

Most of the data accumulated throughout the years on investigation of catalytic antibodies indicate that their production increases on the background of autoimmune abnormalities. The different approaches to induction of catalytic response toward recombinant gp120 HIV-1 surface protein in mice with various autoimmune pathologies are described. The peptidylphosphonate conjugate containing structural part of gp120 molecule is used for reactive immunization of NZB/NZW F1, MRL, and SJL mice. The specific modification of heavy and light chains of mouse autoantibodies with Val-Ala-Glu-Glu-Glu-Val-PO(OPh)2 reactive peptide was demonstrated. Increased proteolytic activity of polyclonal antibodies in SJL mice encouraged us to investigate the production of antigen-specific catalytic antibodies on the background of induced experimental autoimmune encephalomyelitis (EAE). The immunization of autoimmune-prone mice with the engineered fusions containing the fragments of gp120 and encephalitogenic epitope of myelin basic protein (MBP(89-104)) was made. The proteolytic activity of polyclonal antibodies isolated from the sera of autoimmune mice immunized by the described antigen was shown. Specific immune response of SJL mice to these antigens was characterized. Polyclonal antibodies purified from sera of the immunized animals revealed proteolytic activity. The antiidiotypic approach to raise the specific proteolytic antibody as an "internal image" of protease is described. The "second order" monoclonal antibodies toward subtilisin Carlsberg revealed pronounced proteolytic activity.

[Structural-functional study of recombinant forms of onconase]

A method for expression of an onconase gene leading to a soluble form of the protein was developed. The enzymatic and cytotoxic properties of the protein's recombinant forms were studied. Recombinant onconase with an additional N-terminal Met residue isolated in nondenaturing conditions did not substantially differ from the native enzyme in ribonucleolytic activity. The addition of a 33-mer peptide containing auxiliary elements for the simplification of isolation and detection of the recombinant protein did not affect the enzyme properties of onconase. The method proposed is useful for the onconase structure-function relation studies and enables construction of onconase-based fusion proteins for anticancer therapy.

New experimental model of multiple myeloma

NSO/1 (P3x63Ay 8Ut) and SP20 myeloma cells were inoculated to BALB/c OlaHsd mice. NSO/1 cells allowed adequate stage-by-stage monitoring of tumor development. The adequacy of this model was confirmed in experiments with conventional cytostatics: prospidium and cytarabine caused necrosis of tumor cells and reduced animal mortality.

[Localization of transcripts corresponding to different regions of the "cut" locus in Drosophila embryos]

Transcripts of the cut locus were localized in Drosophila embryos with use of nonradioactive in situ hybridization. DIG-labeled probes were generated from two locus regions located at position -130. Distal and proximal regions were found to be transcribed in the same tissues throughout embryogenesis. As only the proximal region transcript was detected, the conclusion was made that two or more various transcripts derived from different regions of the locus and under common control, are present simultaneously in the embryonic cells.

[Detection of a new tissue-specific enhancer in the ct6 region of the regulatory region of the drosophila cut locus]

The cut locus of Drosophila is an interesting example of a complex eukaryotic locus responsible for the development of many tissues and organs. Most of this locus is regulatory. The entire locus was cloned by Tchurikov et al. in 1986 and Blochlinger et al. in 1988. The wing ctn enhancer located 80 kb upstream of the promoter was earlier found in a 2.7 kb EcoRI-BamHI DNA fragment. The locus region 65-80 kb remote from the promoter was assumed to control the development of wings and vibrissae. We have found a new enhancer region in the ct6 region of the locus, which was in a 5 kb BamHI-EcoRI DNA fragment adjacent to the ctn enhancer. This region is responsible for the expression of the reporter lacZ gene in many tissues and organs at all stages of Drosophila development (at least in the intestine, Malpighian tubules, thoracic and abdominal sensory organs, thoracic ganglia and in ring glands). Thus, the region located 75 kb upstream of the promoter has some properties of the locus control region (LCR).

Forum domain in Drosophila melanogaster cut locus possesses looped domains inside

We have studied the relationship between chromosomal forum domains and looped domains in the cut locus of Drosophila melanogaster . Forum domains were earlier detected by separation in pulsed-field gels of 50-150 kb chromosomal DNA fragments obtained after spontaneous non-random degradation of chromosomes. We have localized the boundary region where cleavage sites are scattered between two forum domains in the regulatory region of the cut locus. We have sequenced a 13 kb region spanning few kilobases from distal domain, the boundary region and part of the proximal forum domain where several scaffold associated regions (SARs) were observed. We conclude that forum domains and looped domains are physically different types of domains and belong to different levels of organization in eukaryotic chromosomes. The boundary region between the neighboring forum domains in the cut locus possesses the Doc element insertion and a micro-satellite stretch and thus might remind a small island of heterochromatin and correspond to so-called intercalary heterochromatin that is known to be located in the 7B1-2 band where the major part of the cut locus is reside.

Burdock, a novel retrotransposon in Drosophila melanogaster, integrates into the coding region of the cut locus

The burdock element is known to be the 2.6-kb insertion into the same region of the cut locus in 12 independently obtained ct-lethal mutants. Here we have determined the complete sequences of this insertion and of the hot spot region. It was found that the burdock is a short retrotransposon with long terminal repeats and a single open reading frame (ORF). The polypeptide encoded by the burdock ORF contains two adjacent regions homologous to the gag and pol polyproteins of the gypsy mobile element. The burdock insertion interrupts the short ORF of the cut locus. The target site sequence of the burdock insertions is similar to the Drosophila topoisomerase II cleavage site.