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Kozyr A.V.,State Research Center for Applied Microbiology and Biotechnology | Kolesnikov A.V.,Institute of Immunological Engineering | Khlyntseva A.E.,State Research Center for Applied Microbiology and Biotechnology | Bogun A.G.,State Research Center for Applied Microbiology and Biotechnology | And 3 more authors.
Autoimmune Diseases | Year: 2012

Anti-DNA autoantibodies are responsible for tissue injury in lupus. A subset of DNA-specific antibodies capable of DNA cleavage can be even more harmful after entering the living cells by destroying nuclear DNA. Origins of anti-DNA autoantibodies are not fully understood, and the mechanism of induction of DNA-cleaving activity remains speculative. The autoantibody BV04-01 derived from lupus-prone mouse is the only DNA-hydrolyzing immunoglobulin with known 3D structure. Identification and analysis of antibodies homologous to BV04-01 may help to understand molecular bases and origins of DNA-cleaving activity of autoantibodies. BLAST search identified murine anti-DNA autoantibody MRL-4 with sequences of variable region genes highly homologous to those of autoantibody BV04-01. Despite significant homology to BV04-01, not only MRL-4 had no DNA-cleaving activity, but also reversion of its unusual P23 mutation to the germline alanine resulted in a dramatic loss of affinity to DNA. Contrary to this effect, transfer of the P23 mutation to the BV04-01 has resulted in a significant drop in DNA binding and almost complete loss of catalytic activity. In the present paper we analyzed the properties of two homologous autoantibodies and mutants thereof and discussed the implications of unusual somatic mutations for the development of autoantibodies with DNA-binding and DNA-hydrolyzing activity. © 2012 A. V. Kozyr et al. Source

Sergienko O.V.,Russian Academy of Agricultural Sciences | Aksenova E.I.,Gamaleya Institute of Epidemiology and Microbiology | Lyashchuk A.M.,Gamaleya Institute of Epidemiology and Microbiology | Galushkina Z.M.,Gamaleya Institute of Epidemiology and Microbiology | And 13 more authors.
Molecular Genetics, Microbiology and Virology | Year: 2012

The genes of ESAT-6, CFP-10 and Ag85A secreted antigens of Mycobacterium tuberculosis were cloned in Escherichia coli. Fusion proteins Esat6-CBD, Ag85A-CBD and CFP10-CBD with thermostable cellulose binding domain (CBD) of Anaerocellum thermophilum providing high affinity to cellulose were constructed. Content of the fused proteins in overproducing strains was 20% of total protein for CFP10-CBD and 15% for both Esat6-CBD and Ag85A-CBD. Immobilization of the fusion proteins on cellulose is a one-stage process that provides simultaneous antigen purification and absorption on cellulose. The proteins retain their antigenic properties and can be used as the components for subunit tuberculosis vaccine production or in diagnostic kits. © 2012 Allerton Press, Inc. Source

Arshad N.M.,University of Malaya | In L.L.A.,University of Kuala Lumpur | Soh T.L.,University of Kuala Lumpur | Azmi M.N.,University of Malaya | And 5 more authors.
Oncotarget | Year: 2015

Purpose: Previous in vitro and in vivo studies have reported that 1'-S-1'-acetoxychavicol acetate (ACA) isolated from rhizomes of the Malaysian ethnomedicinal plant Alpinia conchigera Griff(Zingiberaceae) induces apoptosis-mediated cell death in tumour cells via dysregulation of the NF-κB pathway. However there were some clinical development drawbacks such as poor in vivo solubility, depreciation of biological activity upon exposure to an aqueous environment and non-specific targeting of tumour cells. In the present study, all the problems above were addressed using the novel drug complex formulation involving recombinant human alpha fetoprotein (rhAFP) and ACA. Experimental Design: To study the synergistic effect of both agents on human cancer xenografts, athymic nude (Nu/Nu) mice were used and treated with various combination regimes intraperitoneally. Serum levels of tumour markers for carcinoembryonic antigen (CEA) and prostate specific antigen (PSA) were assessed using sandwich ELISA. IHC and Western blotting were also conducted on in vivo tumour biopsies to investigate the involvement of NF-κB regulated genes and inflammatory biomarkers. Quantification and correlation between drug efficacies and AFP-receptors were done using IF-IC and Pearson's correlation analysis. Results: Mice exposed to combined treatments displayed higher reductions in tumour volume compared to stand alone agents, consistent with in vitro cytotoxicity assays. Milder signs of systemic toxicity, such as loss in body weight and inflammation of vital organs were also demonstrated compared to stand alone treatments. Tumour marker levels were consistent within all rhAFP/ACA treatment groups where levels of CEA and PSA were initially elevated upon commencement of treatment, and consecutively reduced corresponding to a decrease in tumour bulk volume. Both IHC and Western blotting results indicated that the combined action of rhAFP/ACA was not only able to down-regulate NF-κB activation, but also reduce the expression of NF-κB regulated genes and inflammatory biomarkers. The efficacy of rhAFP/ACA complex was also found to be weakly negatively correlated to the level of surface AFP-receptors between tumour types. Conclusions: This drug complex formulation shows great therapeutic potential against AFP-receptor positive tumours, and serves as a basis to overcome insoluble and nonspecific anti-neoplastic molecules. Source

Ryazantsev S.,University of California at Los Angeles | Tischenko V.,Russian Academy of Sciences | Nguyen C.,University of California at Los Angeles | Abramov V.,Institute of Immunological Engineering | Zav'yalov V.,University of Turku
PLoS ONE | Year: 2013

Human immunoglobulin G, subclass 2 (hIgG2), plays an important role in immunity to bacterial pathogens and in numerous pathological conditions. However, there is a lack of information regarding the three-dimensional (3D) structure of the hIgG2 molecule. We used electron microscopy (EM), differential scanning microcalorimetry (DSC) and fluorescence for structural analysis of the hIgG2. DSC and fluorescence indicated two types of interaction between CH1 domain of Fab (antigen-binding fragment/subunit) and CH2 domain of Fc (complement fixation fragment/subunit) simultaneously present in the sample: close interaction, which increases the thermostability of both, CH1 and CH2 domains, and weak (or no) interaction, which is typical for most IgGs but not hIgG2. Thermodynamics could not determine if both types of interactions are present within a single molecule. To address this question, EM was used. We employed a single-particle reconstruction and negative staining approach to reveal the three-dimensional structure of the hIgG2. A three-dimensional model of hIgG2 was created at 1.78 nm resolution. The hIgG2 is asymmetrical: one Fab subunit is in close proximity to the upper portion of the Fc subunit (CH2 domain) and the other Fab is distant from Fc. The plane of Fab subunits is nearly perpendicular to Fc. EM structure of the hIgG2 is in good agreement with thermodynamic data: a Fab distant from Fc should exhibit a lower melting temperature while a Fab interacting with Fc should exhibit a higher melting temperature. Both types of Fab subunits exist within one molecule resembling an A/B hIgG2 isoform introduced earlier on physicochemical level by Dillon et al. (2008). In such an arrangement, the access to the upper portion of Fc subunit is partially blocked by a Fab subunit. That might explain for instance why hIgG2 mildly activates complement and binds poorly to Fc receptors. Understanding of the three-dimensional structure of the hIgG2 should lead to better design of antibody-based therapeutics. © 2013 Ryazantsev et al. Source

Abramov V.,Institute of Immunological Engineering | Khlebnikov V.,Institute of Immunological Engineering | Kosarev I.,Institute of Immunological Engineering | Bairamova G.,Research Center for Obstetrics | And 10 more authors.
Probiotics and Antimicrobial Proteins | Year: 2014

Lactobacillus crispatus 2029 isolated upon investigation of vaginal lactobacilli of healthy women of reproductive age was selected as a probiotic candidate. The aim of the present study was elucidation of the role of L. crispatus 2029 in resistance of the female reproductive tract to genitourinary pathogens using cervicovaginal epithelial model. Lactobacilluscrispatus 2029 has surface layers (S-layers), which completely surround cells as the outermost component of their envelope. S-layers are responsible for the adhesion of lactobacilli on the surface of cervicovaginal epithelial cells. Study of interactions between L. crispatus 2029 and a type IV collagen, a major molecular component of epithelial cell extracellular matrix, showed that 125I-labeled type IV collagen binds to lactobacilli with high affinity (Kd = (8.0 ± 0.7) × 10−10 M). Lactobacilluscrispatus 2029 consistently colonized epithelial cells. There were no toxicity, epithelial damage and apoptosis after 24 h of colonization. Electronic microscope images demonstrated intimate association between L. crispatus 2029 and epithelial cells. Upon binding to epithelial cells, lactobacilli were recognized by toll-like 2/6 receptors. Lactobacilluscrispatus induced NF-κB activation in epithelial cells and did not induce expression of innate immunity mediators IL-8, IL-1β, IL-1α and TNF-α. Lactobacilluscrispatus 2029 inhibited IL-8 production in epithelial cells induced by MALP-2 and increased production of anti-inflammatory cytokine IL-6, maintaining the homeostasis of female reproductive tract. Lactobacilluscrispatus 2029 produced H2O2 and provided wide spectrum of antagonistic activity increasing colonization resistance to urinary tract infections by bacterial vaginosis and vulvovaginal candidiasis associated agents. © 2014, Springer Science+Business Media New York. Source

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