[The effect of neuroprotector isatin on binding of some model proteins with beta-amyloid peptide: a biosensor study]

The amyloid-beta peptide 1-42 formed during proteolytic processing of the amyloid precursor protein (APP) plays a key role in the development or progression of Alzheimer's disease (AD) and other pathologies associated with formation of protein aggregates in the central nervous system. Recent proteomic profiling of mouse and rat brain preparations by means of beta-amyloid peptide immobilized on Affigel-10 revealed a large group of amyloid-binding proteins (n>80). Many (about 25%) of these proteins were previously identified as isatin-binding proteins. The aim of this study was to validate direct interaction between beta-amyloid peptide and highly purified intact and oxidized peroxiredoxin, M-type pyruvate kinase, alpha-enolase, and the effect of isatin on this interaction. The study performed using SPR-based Biacore 3000 and Biacore X100 biosensors has shown that all the proteins form molecular complexes with immobilized beta-amyloid peptide. The Kd values for these complexes varied from 8.36х10-8 M (peroxiredoxin) to 1.97х10-6 M (alpha-enolase). Oxidative modification of investigated proteins caused opposite effects on complexes of these peptides with beta-amyloid. The endogenous neuroprotector isatin increased dissociation of complexes formed by beta-amyloid peptide with both intact proteins (peroxiredoxin, glyceraldehyde-3-phosphate dehydrogenase) and/or oxidized proteins (peroxiredoxin, pyruvate kinase) used in this study.

Zinc-induced heterodimer formation between metal-binding domains of intact and naturally modified amyloid-beta species: implication to amyloid seeding in Alzheimer's disease?

Zinc ions and modified amyloid-beta peptides (Aβ) play a critical role in the pathological aggregation of endogenous Aβ in Alzheimer's disease (AD). Zinc-induced Aβ oligomerization is mediated by the metal-binding domain (MBD) which includes N-terminal residues 1-16 (Aβ1-16). Earlier, it has been shown that Aβ1-16 as well as some of its naturally occurring variants undergoes zinc-induced homodimerization via the interface in which zinc ion is coordinated by Glu11 and His14 of the interacting subunits. In this study using surface plasmon resonance technique, we have found that in the presence of zinc ions Aβ1-16 forms heterodimers with MBDs of two Aβ species linked to AD: Aβ containing isoAsp7 (isoAβ) and Aβ containing phosphorylated Ser8 (pS8-Aβ). The heterodimers appear to possess the same interface as the homodimers. Simulation of 200 ns molecular dynamic trajectories in two constructed models of dimers ([Aβ1-16/Zn/Aβ1-16] and [isoAβ1-16/Zn/Aβ1-16]), has shown that conformational flexibility of the N-terminal fragments of the dimer subunits is controlled by the structure of corresponding sites 6-8. The data suggest that isoAβ and pS8-Aβ can be involved in the AD pathogenesis by means of their zinc-dependent interactions with endogenous Aβ resulting in the formation of heterodimeric seeds for amyloid aggregation.

[Use of stents with bioactive coating in treatment of patients with lesions of the superficial femoral artery]

The authors analysed the immediate outcomes of implanting stents with bioactive coating in treatment of patients presenting with atherosclerotic lesions of the superficial femoral artery. Over the period from January 2014 to December 2015, endovascular interventions on the superficial femoral artery were carried out in a total of 18 patients (mean age 61.3±9.2 years). The implants inserted were stents with bioactive coating based on titanium oxinitride, measuring 6 to 8 mm in diameter and being from 50 to 200 mm long. Prior to operation and 7 days after implantation of the stent, the immunoenzymatic assay was used to determine the level of nitrogen nitric oxide (NO) in blood. The stents' patency was assessed by the findings of ultrasound duplex scanning performed at 30 days, and then 6 and 12 months after the intervention. There were no complications either during the operation or in the early postoperative period. An increase in the ankle-brachial index was observed in all patients: with the average value prior to treatment amounting to 0.4±0.3 and equalling 1.1±0.2 after stenting (p<0.0001). Normalization of the blood NO level was revealed (was noted to normalize): the mean value prior to operation amounted to 18.9±2.3 µmol/L and after operation to 28.9±4.1 µmol/L (p<0.05). Primary patency rate of the stents was 100% at 30 days, 94.5% (1 occlusion) at 6 months and 88.8% (1 restenosis and 1 occlusion) at 12 months. The patients with occlusion or restenosis were subjected to repeat endovascular interventions, with restoration of patency of the construction (with the construction's patency restored). By now all the 18 patients show preserved patency (currently patency was preserved) of lower-limb arteries, with no evidence of restenosis in the zones of operations. It was concluded that using stents with bioactive coating based on titanium oxinitride results in normalization of the level of NO in blood, which may contribute favourably to prolongation of the period of functioning of endovascular constructions. The first data concerning primary patency of stents of this type make it possible to count on betterment of the remote results of treatment of patients presenting with atherosclerotic lesions of the superficial femoral artery.

[Influence of gravity discharge on the content of isatin-binding proteins in mice: results of ground-based and space research under the program Bion-M №1]

Isatin-binding activity of mice liver proteins has been investigated in the samples from the control and flight groups by using the methods of biosensor and proteomic analysis. It was found the higher isatin-binding activity in mice of flight group. The content of a number of individual isatin-binding proteins in the samples of the flight groups differ slightly from the ground control. However, in samples from animals which have weekly post-flight adaptation, the level of certain proteins was significantly increased. The latter allows us to assume that the main events in the proteome of mice (at least in subproteome of isatin-binding proteins), occurs in early post-flight period.

[Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes b5]

Molecular interactions between proteins redox partners (cytochromes Р450 3А4, 3А5 and cytochrome b5) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes Р450 3А4 and 3А5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b5: the microsomal (b5mc) and mitochondrial (b5om) forms of this protein, as well as with 2 "chimeric" proteins, b5(om-mc), b5(mc-om). Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om. Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om, b5(om-mc), and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435  -0.350 V (vs. Ag/AgCl). Cytochrome b5mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 in the presence of its substrate testosterone.

Computer-aided design of aptamers for cytochrome p450

Aptamers are short single-stranded DNA or RNA oligonucleotides that can bind to their targets with high affinity and specificity. Usually, they are experimentally selected using the SELEX method. Here, we describe an approach toward the in silico selection of aptamers for proteins. This approach involves three steps: finding a potential binding site, designing the recognition and structural parts of the aptamers and evaluating the experimental affinity. Using this approach, a set of 15-mer aptamers for cytochrome P450 51A1 was designed using docking and molecular dynamics simulation. An experimental evaluation of the synthesized aptamers using SPR biosensor showed that these aptamers interact with cytochrome P450 51A1 with Kd values in the range of 10(-6)-10(-7) M.

[Effect of mutations and modifications of amino acid residues on zinc-induced interaction of the metal-binding domain of β-amyloid with DNA]

Interaction of intranuclear β-amyloid with DNA is considered to be a plausible mechanism of Alzheimer's disease pathogenesis. The interaction of single- and double-stranded DNA with synthetic peptides was analyzed using surface plasmon resonance. The peptides represent the metal-binding domain of β-amyloid (amino acids 1-16) and its variants with chemical modifications and point substitutions of amino acid residues which are associated with enhanced neurotoxicity of β-amyloid in cell tests. It has been shown that the presence of zinc ions is necessary for the interaction of the peptides with DNA in solution. H6R substitution has remarkably reduced the ability of domain 1-16 to bind DNA. This is in accordance with the supposition that the coordination of a zinc ion by amino acid residues His6, Glu11, His13, and His14 of the β-amyloid metal-binding domain results in the occurrence of an anion-binding site responsible for the interaction of the domain with DNA. Zinc-induced dimerization and oligomerization of domain 1-16 associated with phosphorylation of Ser8 and the presence of unblocked amino- and carboxy-terminal groups have resulted in a decrease of peptide concentrations required for detection of the peptide-DNA interaction. The presence of multiple anion-binding sites on the dimers and oligomers is responsible for the enhancement of the peptide-DNA interaction. A substitution of the negatively charged residue Asp7 for the neutral residue Asn in close proximity to the anion-binding site of the domain 1-16 of Aβ facilitates the electrostatic interaction between this site and phosphates of a polynucleotide chain, which enhances zinc-induced binding to DNA.

[Optical surface plasmon resonance biosensors in molecular fishing]

An optical biosensor employing surface plasmon resonance is a highly efficient instrument applicable for direct real time registration of molecular interactions without additional use of any labels or coupled processes. As an independent approach it is especially effective in analysis of various ligand receptor interactions. SPR-biosensors are used for validation of studies on intermolecular interactions in complex biological systems (affinity profiling of various groups of proteins, etc.). Recently, potential application of the SPR-biosensor for molecular fishing (direct affinity binding of target molecules from complex biological mixtures on the optical biosensor surface followed by their elution for identification by LC-MS/MS) has been demonstrated. Using SPR-biosensors in such studies it is possible to solve the following tasks: (a) SPR-based selection of immobilization conditions required for the most effective affinity separation of a particular biological sample; (b) SPR-based molecular fishing for subsequent protein identification by mass spectrometry; (c) SPR-based validation of the interaction of identified proteins with immobilized ligand. This review considers practical application of the SPR technology in the context of recent studies performed in the Institute of Biomedical Chemistry on molecular fishing of real biological objects.

[Computer modelling of monoaminoxidases]

The article summarized results of studies on active site structures of monoamine oxidases (MAO) performed in the Institute of Biomedical Chemistry (Russia) by computer modelling approaches. MAO, catalyzing the reaction of oxidative deamination of major neurotransmitter monoamines, exists in two highly homologous forms, MAO A and MAO B, distinguished by substrate specificity and inhibitor selectivity. The development of approaches for active site modelling of these enzymes (with unknown three-dimensional structures) started from analysis of relationship between the geometrical sizes of rigid indole and isatin derivatives and their inhibitory activity. These studies resulted in molding of the active site structures of MAO A and MAO B. These molds reflect the sizes and shapes of active sites of these enzymes. These mold models have been used for virtual screening of molecular databases for new inhibitors. The models obtained at different stages of MAO investigations have been compared with recently appeared three-dimensional structures of MAO A and MAO B.

[The screening of the inhibitors of the human cytochrome P450(51) (CYP51A1): the plant and animal structural lanosterol's analogs]

The cholesterol biosynthesis regulation is the important part of the hypercholesterolemia diseases therapy. The inhibition of the post-squalene cholesterol biosynthesis steps provide the alternative to classic statin therapy. Sterol-14a-demethylase (CYP51) is one of the hypothetical targets for it. In this work the screening of the ability to interact with human CYP51 (CYP51A1) for the nature low-weight compounds with steroid-like scaffold were performed by integration of the surface plasmon resonance biosensor and spectral titration methods. The results of the selection were 4 compounds (betulafolientriol, holothurin A, teasaponin, capsicoside A) witch had high affinity to the CYP51A1 active site. These data extend the range of compounds which may be used as specific inhibitors of CYP51 and give the permission to suggest the dynamic of the enzyme.

[The use of immobilized ubiquitin for biosensor analysis of the mitochondrial subinteractome]

Protein ubiquitination is considered as an important mechanism that is responsible not only for specific labeling of proteins for their subsequent degradation but also for localization of proteins in the cell and regulation of protein-protein interactions. In the context of protein-protein interactions binding of (mono/poly)ubiquitinated molecules to proteins containing specific ubiquitin binding domains appear to play the decisive role. Although formation of the ubiquitin interactome has been demonstrated for cytosol, involvement of mitochondria and associated extramitochondrial proteins into such interactions still requires detailed investigation. In this study using an optical biosensor we have demonstrated binding of proteins of mouse brain mitochondrial lysates to immobilized monomeric ubiquitin. Model purified proteins, which are known to be associated with the outer mitochondrial compartment (glyceraldehyde-3-phosphate dehydorgenase, creatine phosphokinase), interacted with immobilized ubiquitin as well as with each other. This suggests that (poly)ubiquitinated chains may be involved in protein-protein interactions between ubiquitinated and non-ubiquitinated proteins and thus may contribute to formation of (mitochondrial) ubiquitin subinteractome.

[ENDOVASCULAR ABDOMINAL AORTIC ANEURISM REPAIR]

The authors analyzed the single-center experience of treatment of 72 patients with abdominal aortic aneurisms and severe accompanied pathology. The aneurisms were repaired by stent-grafts. All the patients had abdominal aortic aneurisms with the diameters from 41 to 84 mm against the background of severe somatic pathology. It was a contraindication to planned open surgery. An installation of stent-graft was successful in all 72 follow-ups. It wasn't necessary to use a conversion to open surgery. The follow-up period consisted of 44,6?2,1 months. Control ultrasound and computer tomography studies hadn't revealed an increase of aneurism sack sizes or "eakages". A reduction of abdominal aortic aneurism sizes was noted in 37 patients on 4-5% during first year after operation. The stent-graft implantation extends the possibilities of abdominal aortic aneurism treatment for patients from a high surgical risk group.

[WAYS OF IMPROVEMENT OF LOOP ENDARTERECTOMY RESULTS FROM ILIAC-FEMORAL SEGMENT]

The article presents an analysis of treatment results of 91 patients with iliac-femoral segment artery occlusion at the period from 2008 to 2014. Patients were divided into 2 groups: main group (n=30) consisted of patients who undergoing a half-closed loop endarterectomy with following implantation of stent-grafts in this area and control group (n=61) had patients whom were performed routine half-closed loop endarterectomy. The II degree of ischemia of lower extremities was in 88 (96,7%) patients and III degree had 3 (3,3%) patients. The areas of abnormalities of intravascular pattern were detected in 100% of cases in intraoperative angiography. They were modified using stent-grafts. A primary vascular patency was 100% in the first group and it numbered 65% in the second group during 5 years. The intraoperative angiography control with stent-graft implantation to the area of endarterectomy allowed reliable improvement of treatment results.

Protein interactomics based on direct molecular fishing on paramagnetic particles: practical realization and further SPR validation

There is increasing evidence that proteins function in the cell as integrated stable or temporally formed protein complexes, interactomes. Previously, using model systems we demonstrated applicability of direct molecular fishing on paramagnetic particles for protein interactomics (Ershov et al. Proteomics, 2012, 12, 3295). In the present study, we have used a combination of affinity-based molecular fishing and subsequent MS for investigation of human liver proteins involved in interactions with immobilized microsomal cytochrome b5 (CYB5A), and also transthyretin and BSA as alternative affinity ligands (baits). The LC-MS/MS identification of prey proteins fished on these baits revealed three sets of proteins: 98, 120, and 220, respectively. Comparison analysis of these sets revealed only three proteins common for all the baits. In the case of paired analysis, the number of common proteins varied from 2 to 9. The binding capacity of some identified proteins has been validated by a SPR-based biosensor. All the investigated proteins effectively interacted with the immobilized CYB5A (Kd values ranged from 0.07 to 1.1 μM). Results of this study suggest that direct molecular fishing is applicable for analysis of protein-protein interactions (PPI) under normal and pathological conditions, in which altered PPIs are especially important.

[Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes b5]

Molecular interactions between proteins redox partners (cytochromes P450 3A4, 3A5 and cytochrome b5) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes P450 3A4 and 3A5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b5: the microsomal (b5mc) and mitochondrial (b5om) forms of this protein, as well as with 2 "chimeric" proteins, b5(om-mc), b5(mc-om). Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om. Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om, b5(om-mc), and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435 - -0.350 V (vs. Ag/AgCl). Cytochrome b5mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 to testosterone.

Zinc-induced interaction of the metal-binding domain of amyloid-β peptide with DNA

The interaction of the 16-mer synthetic peptide (Aβ16), which represents the metal-binding domain of the amyloid-β with DNA, was studied employing the surface plasmon resonance technique. It has been shown that Aβ16 binds to the duplex DNA in the presence of zinc ions and thus the metal-binding domain can serve as a zinc-dependent DNA-binding site of the amyloid-β. The interaction of Aβ16 with DNA most probably depends on oligomerization of the peptide and is dominated by interaction with phosphates of the DNA backbone.

[Protocols of proteins interactomics: molecular fishing on optical chips and magnetic nanoparticles]

Now it is absolutely clear, that the majority of proteins in living systems function due to interaction with each other in stable or dynamic proteins complexes. Therefore necessity of deeper studies of proteins functions causes expansion of protein-protein interaction research. In the present review the brief description and comparative estimation of experimental methods and protocols of protein interactomics, based on technology of molecular fishing on an optical chips and paramagnetic nanoparticles is given.

[Medico-social and psychosomatic status of gerontostomatologic patients]

Assessment of medico-social and psychosomatic status of patients of the advanced and senile age having dental diseases was carried out. The results of the study show that the level of stomatological morbidity in this contingent of patients is rather high, and the treatment must be carried out with obligatory participation of doctors-interns and taking into account mental health of a person.

Chromosome 18 transcriptome profiling and targeted proteome mapping in depleted plasma, liver tissue and HepG2 cells

The final goal of the Russian part of the Chromosome-centric Human Proteome Project (C-HPP) was established as the analysis of the chromosome 18 (Chr 18) protein complement in plasma, liver tissue and HepG2 cells with the sensitivity of 10(-18) M. Using SRM, we have recently targeted 277 Chr 18 proteins in plasma, liver, and HepG2 cells. On the basis of the results of the survey, the SRM assays were drafted for 250 proteins: 41 proteins were found only in the liver tissue, 82 proteins were specifically detected in depleted plasma, and 127 proteins were mapped in both samples. The targeted analysis of HepG2 cells was carried out for 49 proteins; 41 of them were successfully registered using ordinary SRM and 5 additional proteins were registered using a combination of irreversible binding of proteins on CN-Br Sepharose 4B with SRM. Transcriptome profiling of HepG2 cells performed by RNAseq and RT-PCR has shown a significant correlation (r = 0.78) for 42 gene transcripts. A pilot affinity-based interactome analysis was performed for cytochrome b5 using analytical and preparative optical biosensor fishing followed by MS analysis of the fished proteins. All of the data on the proteome complement of the Chr 18 have been integrated into our gene-centric knowledgebase ( www.kb18.ru ).

Highly sensitive detection of human cardiac myoglobin using a reverse sandwich immunoassay with a gold nanoparticle-enhanced surface plasmon resonance biosensor

A highly sensitive reverse sandwich immunoassay for the detection of human cardiac myoglobin (cMb) in serum was designed utilizing a gold nanoparticle (AuNP)-enhanced surface plasmon resonance (SPR) biosensor. First, a monoclonal anti-cMb antibody (Mab1) was covalently immobilized on the sensor surface. AuNPs were covalently conjugated to the second monoclonal anti-cMb antibody (Mab2) to form an immuno-gold reagent (Mab2-AuNP). The reverse sandwich immunoassay consists of two steps: (1) mixing the serum sample with Mab2-AuNP and incubation for the formation of cMb/Mab2-AuNP complexes and (2) sample injection over the sensor surface and evaluation of the Mab1/cMb/Mab2-AuNP complex formation, with the subsequent calculation of the cMb concentration in the serum. The biosensor signal was amplified approximately 30-fold compared with the direct reaction of cMb with Mab1 on the sensor surface. The limit of detection of cMb in a human blood serum sample was found to be as low as 10 pM (approx. 0.18 ng mL(-1)), and the inter-assay coefficient of variation was less than 3%. Thus, the developed SPR-based reverse sandwich immunoassay has a sensitivity that is sufficient to measure cMb across a wide range of normal and pathological concentrations, allowing an adequate estimation of the disease severity and the monitoring of treatment.

Magnetophoresis of particles and aggregates in concentrated magnetic fluids

Experimental and theoretical studies were carried out to investigate the problem of magnetophoresis in a thin layer of concentrated magnetic fluids, concerning the aspect of particle aggregation. A heuristic theoretical model, describing diffusion fluxes of individual and aggregated particles, is suggested. The solution of related diffusion and magnetostatic problems are compared with the experimental data. The analysis of the data shows that the aggregates essentially change the concentration profile. Good agreement between experimental and theoretical curves is observed in the case when the aggregates contain, on average, more than ten particles.

[Thermodynamic analysis of dimerization inhibitors binding to HIV protease monomers]

Here, we describe the analysis of kinetic and thermodynamic parameters for binding of peptide and nonpeptide dimerization inhibitors to immobilized HIV protease (HIVp) monomers by using surface plasmon resonance. Molecular interactions were investigated at different inhibitors concentrations (0-80 microM) and temperatures (15-35 degrees C). The kinetic, equilibrium and thermodynamic parameters have been determined. It was found that both inhibitors were characterized by similar interaction parameters. The complex formation is entropically driven process for both inhibitors. The entropic term(-TdeltaS) had the value about -20 kcal/mol while the enthalpic term (deltaH) had the positive value about 14 kcal/mol and counteracted the complex formation.

Interplay of low-energy phonons and magnetic excitations in the Kondo insulator YbB12

Peculiarities in the lattice dynamics of the Kondo insulator Y bB(12) have been studied by inelastic neutron scattering. Selected phonon modes were traced above and below the temperature region (T ~ 50 K) where the gap opens in the electron density of states. The intensities of some low-energy modes exhibit an anomalous temperature dependence for q vectors close to the Brillouin zone boundary, suggesting a renormalization of the phonon eigenvectors. This effect is thought to arise from a coupling with magnetic excitations of the same symmetry, which exist at nearby energies. It is argued that this magnetovibrational coupling may in turn play a role in the steep temperature crossover existing in Y bB(12) between the low-temperature (Kondo insulator) and high-temperature (incoherent spin-fluctuation) regimes, which is rapidly suppressed by lighter Zr substitution.

PROTEIN–PROTEIN INTERACTIONS AS NEW TARGETS FOR DRUG DESIGN: VIRTUAL AND EXPERIMENTAL APPROACHES

Protein–protein and protein–ligand interactions play a central role in biochemical reactions, and understanding these processes is an important task in different fields of biomedical science and drug discovery. Proteins often work in complex assemblies of several macromolecules and small ligands. The structural and functional description of protein–protein interactions (PPI) is very important for basic-, as well as applied research. The interface areas of protein complexes have unique structure and properties, so PPI represent prospective targets for a new generation of drugs. One of the key targets of PPI inhibitors are oligomeric enzymes. This report shows interactive links between virtual and experimental approaches in a total pipeline "from gene to drug" and using Surface Plasmon Resonance technology for experimentally assessing PPI. Our research is conducted on two oligomeric enzymes — HIV-1 protease (HIVp) (homo-dimer) and bacterial L-asparaginase (homo-tetramer). Using methods of molecular modeling and computational alanine scanning we obtained structural and functional description of PPI in these two enzymes. We also presented a real example of application of integral approach in searching inhibitors of HIVp dimerization — from virtual database mining up to experimental testing of lead compounds.

Combinatorial antibody library from multiple sclerosis patients reveals antibodies that cross-react with myelin basic protein and EBV antigen

Multiple sclerosis (MS) is a widespread neurodegenerative autoimmune disease with unknown etiology. It is increasingly evident that, together with pathogenic T cells, autoreactive B cells are among the major players in MS development. The analysis of myelin neuroantigen-specific antibody repertoires and their possible cross-reactivity against environmental antigens, including viral proteins, could shed light on the mechanism of MS induction and progression. A phage display library of single-chain variable fragments (scFvs) was constructed from blood lymphocytes of patients with MS as a potential source of representative MS autoantibodies. Structural alignment of 13 clones selected toward myelin basic protein (MBP), one of the major myelin antigens, showed high homology within variable regions with cerebrospinal fluid MS-associated antibodies as well as with antibodies toward Epstein-Barr latent membrane protein 1 (LMP1). Three scFv clones showed pronounced specificity to MBP fragments 65-92 and 130-156, similar to the serum MS antibodies. One of these clones, designated E2, in both scFv and full-size human antibody constructs, was shown to react with both MBP and LMP1 proteins in vitro, suggesting natural cross-reactivity. Thus, antibodies induced against LMP1 during Epstein-Barr virus infection might act as inflammatory trigger by reacting with MBP, suggesting molecular mimicry in the mechanism of MS pathogenesis.