Fusion with an albumin-binding domain improves pharmacokinetics of an αvß3-integrin binding fibronectin scaffold protein.

Fusion with an albumin-binding domain (ABD) of streptococcal protein G represents a popular approach for half-life extension of small protein therapeutics in the organism. To increase the circulation time of engineered αvß3-integrin-binding protein (JCL) based on the 10th human fibronectin type III domain (10 Fn3), we have constructed several fusions with ABD with different orientations of the partner proteins and linker length. The recombinant proteins were expressed in Escherichia coli cells and purified by nickel-affinity chromatography. All fusion proteins bound human serum albumin (HSA) in ELISA assay; however, fusions with longer linkers demonstrated better performance. Interaction of ABD-L15 -JCL and JCL-L14 -ABD with HSA was confirmed by analytical size exclusion chromatography and pull-down assays. Surprisingly, the thermal stability of ABD-L15 -JCL was dramatically decreased in comparison with JCL and JCL-L14 -ABD proteins. Pharmacokinetic studies revealed that JCL-L14 -ABD circulated in murine blood about 10 times longer than ABD-L15 -JCL and 960 times longer than JCL. Biodistribution studies of JCL-L14 -ABD in mice revealed its increased level in blood and a decreased accumulation in liver and kidneys in comparison with JCL. Obtained results demonstrate the utility of the fusion with ABD for half-life extension of the binding proteins based on 10 Fn3.

Construction of Artificial TNF-Binding Proteins Based on the 10th Human Fibronectin Type III Domain Using Bacterial Display.

Construction of antibody mimetics on the base of alternative scaffold proteins is a promising strategy for obtaining new products for medicine and biotechnology. The aim of our work was to optimize the cell display system for the 10th human fibronectin type III domain (10Fn3) scaffold protein based on the AT877 autotransporter from Psychrobacter cryohalolentis K5T and to construct new artificial TNF-binding proteins. We obtained a 10Fn3 gene combinatorial library and screened it using the bacterial display method. After expression of the selected 10Fn3 variants in Escherichia coli cells and analysis of their TNF-binding activity, we identified proteins that display high affinity for TNF and characterized their properties.

Fusion with the cold-active esterase facilitates autotransporter-based surface display of the 10th human fibronectin domain in Escherichia coli.

Cell surface display is a popular approach for the construction of whole-cell biocatalysts, live vaccines, and screening of combinatorial libraries. To develop a novel surface display system for the popular scaffold protein 10th human fibronectin type III domain (10Fn3) in Escherichia coli cells, we have used an α-helical linker and a C-terminal translocator domain from previously characterized autotransporter from Psychrobacter cryohalolentis K5T. The level of 10Fn3 passenger exposure at the cell surface provided by the hybrid autotransporter Fn877 and its C-terminal variants was low. To improve it, the fusion proteins containing 10Fn3 and the native autotransporter passenger Est877 or the cold-active esterase EstPc in different orientations were constructed and expressed as passenger domains. Using the whole-cell ELISA and activity assays, we have demonstrated that N-terminal position of EstPc in the passenger significantly improves the efficiency of the surface display of 10Fn3 in E. coli cells.

[Fluorescent fusion proteins with 10th human fibronectin domain].

In the current paper we describe a new type of hybrid molecules including red fluorescent protein mCherry and 10th type III human fibronectin domain (10Fn3) - one of the alternative scaffold proteins which can be used for the construction of antibody mimics with various binding specificity. We have constructed different gene variants encoding for the hybrid fluorescent protein and studied their expression in Escherichia coli cells. It was shown that N-terminal position of mCherry and modification of its N-terminal amino acid sequence promotes efficientbacterial expression of the hybrid protein in the soluble form. On the basis of the proposed construction we have obtained the hybrid fluorescent protein ChIBF, containing alphaVbeta3-integrin binding vari- ant of 10Fn3, and demonstrated the possibility of its utilization for the visualization of alphaVbeta3-integrin at the surface of MDCK epithelial cells by confocal microscopy.

Construction of TNF-binding proteins by grafting hypervariable regions of F10 antibody on human fibronectin domain scaffold.

Tumor necrosis factor (TNF) plays a key role in the pathogenesis of various diseases. To study the possibility of constructing TNF-binding proteins by grafting hypervariable regions of immunoglobulins (CDR), we have replaced amino acid sequences of loops from the tenth type III domain of human fibronectin ((10)Fn3) by amino acid sequences of CDR from the light and heavy chains of the anti-TNF antibody F10. The assessment of TNF-binding properties of the resulting proteins by ELISA has revealed the highest activity of Hd3 containing sequences CDR-H1 and CDR-H2 of the antibody F10 and of Hd2 containing sequences CDR-H1 and CDR-H3. The proteins constructed by us on the fibronectin domain scaffold specifically bound TNF during Western blotting and also weakened its cytotoxic effect on L929 line cells. The highest neutralizing activity was demonstrated by the proteins Hd2 and Hd3, which induced, respectively, 10- and 50-fold increase in the EC(50) of TNF.

[Production and properties of human tumor necrosis factor peptide fragments].

The tumor necrosis factor (TNF) is a proinflammatory cytokine that plays a pivotal role in the regulation of the human immune system. Studies of the TNF functional topography are a challenging task in bioengineering. We have produced genes encoding the peptides Dl (3-30), D2 (31-85), D3 (86-114), and D4 (115-157), which correspond to isolated fragments of the informational structure of TNF. These genes were expressed in E. coli cells at a high level in a soluble form. We have shown that hybrid proteins SD2 and SD4 tend to form soluble aggregates, which can be destroyed by urea treatment. Purified peptides Dl, D3, and D4 possess a similar secondary structure with dominating beta-structural elements. The analysis of the biological activity of these peptides has shown that they do not exhibit cytotoxic properties on L929 murine fibroblasts. The simultaneous addition of Dl with full-length TNF results in the concentration dependent suppression of TNF activity.

Novel mutants of human tumor necrosis factor with dominant-negative properties.

Tumor necrosis factor (TNF) is a polyfunctional cytokine, one of the key mediators of inflammation and innate immunity. On the other hand, systemic or local TNF overexpression is typical of such pathological states as rheumatoid arthritis, psoriasis, Crohn's disease, septic shock, and multiple sclerosis. Neutralization of TNF activity has a marked curative effect for some diseases; therefore, the search for various TNF blockers is a promising field of protein engineering and biotechnology. According to the previously developed concept concerning the possibility of designing dominant-negative mutants, the following TNF variants have been studied: TNFY87H + A145R, TNFY87H + A96S + A145R, and TNFV91N + A145R. All of these form inactive TNF heterotrimers with the native protein. The ability of mutants to neutralize the effect of TNF was investigated. The addition of mutants to the native protein was shown to provide a concentration-dependent suppression of TNF cytotoxicity against the mouse fibroblast cell line L929. Thus, novel inhibitors of human TNF can be engineered on the basis of these muteins.

[Recombinant full-size human antibody to Ebola virus].

A full-size human antibody to Ebola virus was constructed by joining genes encoding the constant domains of the heavy and light chains of human immunoglobulin with the corresponding DNA fragments encoding variable domains of the single-chain antibody 4D1 specific to Ebola virus, which was chosen from a combinatorial phage display library of single-strand human antibodies. Two expression plasmids. pCH1 and pCL1, containing the artificial genes encoding the light and heavy chains of human immunoglobulin, respectively, were constructed. Their cotransfection into the human embryonic kidney cell line HEK293T provided the production of a full-size recombinant human antibody. The affinity constant for the antibody was estimated by solid-phase enzyme-linked immunoassay to be 7.7 x 10(7) +/- 1.5 x 10(7) M(-1). Like the parent single-chain antibody 4DI, the resulting antibody bound the nucleoprotein of Ebola virus and did not interact with the proteins of Marburg virus.

[Comparison of adjuvant activities of glucosaminyl-muramyl dipeptide and of the gene coding for granulocyte-macrophage colony-stimulating factor in DNA immunization against herpes simplex virus].

Adjuvant activities of granulocyte-macrophage colony-stimulating factor (GM-CSF) and synthetic glucosaminyl-muramyl dipeptide (GMDP) were studied in immunization against type 1 herpes simplex virus (HSV1). Gene encoding the gD HSV1 protein (pDNAgD) was used as an immunogen. Gene encoding GM-CSF in pDNAGM-CSF plasmid, which was developed for eukaryotic expression, and GM-DP were used as immune response modulators. GMDP and plasmid DNA with inserted GM-CSF gene enhanced T-cell immune response to HSV1 after a single injection (pDNAGM-CSF) or 24 h before (GMDP) immunization with the gD HSV1 gene. Both adjuvants increased protective effect of DNA-immunization by a virus gene with 63 up to 100% after injection of two genes and up to 96% after the viral gene was inoculated 24 h after GMDP. These high effects indicate that further investigation of anti-HSV1 DNA-based vaccines used with genetic and peptide adjuvant is prospective.

Comparative study of macrophage response in mice after DNA immunization and infection with herpes simplex virus type 1.

Functional activity of macrophages and intensity of T cell immune response in mice were studied after intravaginal and intraperitoneal infection with herpes simplex virus type 1 and DNA vaccination in combination with adjuvant treatment (recombinant granulocyte-macrophage colony-stimulating factor and glucosaminylmuramyl dipeptide). DNA vaccination induced a virus-specific T cell immune response with no macrophagic inflammatory reaction. Infection with herpes simplex virus type 1 was accompanied by sustained inflammation, but not by the T cell immune response.

[Effect of tumor necrosis factor DNA on immune response to DNA immunization against herpes simplex virus]. / Vliianie DNK faktora nekroza opukholi na immunnyi otvet pri DNK-immunizatsii protiv virusa prostogo gerpesa.

A study was made of the adjuvant effect of the mouse tumor necrosis factor alpha (mTNF alpha) on DNA immunization against the herpes simplex virus type 1 (HSV1). The HSV1 gD gene (pDNAgD) served as an immunogen; mTNF alpha or its gene cloned in an eukaryotic expression vector (pDNAmTNF) were used to modulate the immune response. Double immunization with pDNAgD led to a sixfold increase in the in vitro T-cell response, a high (1:2000) titer of anti-HSV1 antibodies (including virus-neutralizing antibodies), an increase in IgG2a/IgG1 (suggesting a shift of the immune response to the Th1 type), and no change in CD4/CD8 T-cell ratio. A single injection of mTNF alpha along with inactivated HSV1 allowed a twice higher antibody titer and a fourfold higher T-cell response as compared with immunization with HSV1 alone. Double immunization with both pDNAgD and pDNAmTNF increased the titer of anti-HSV1 antibodies and the T-cell response by factors of 8 and 1.5, respectively, as compared with immunization with pDNAgD alone. However, the protective effect was significantly lower with the two plasmids than with pDNAgD (73 vs. 100%). Thus, DNA immunization with pDNAgD induced both B- and T-cell responses and completely protected mice from a lethal doze of HSV1. The adjuvant properties of mTNF alpha and pDNAmTNF need further investigation.

[Design of chimeric proteins based on a pentameric superhelical fragment of COMP. II. Properties of a hybrid, containing an VNTR (MUC1) antigen of human tumors]. / Konstruirovanie khimernykh belkov na osnove pentamernogo superspiral'nogo fragmenta COMP. II. Svoistva gibrida, soderzhashchego antigen VNTR (MUC1) opukholei cheloveka.

An oligomeric chimeric protein DB-2 was constructed, to design drugs with antitumor activity and to develop highly sensitive immunospecific tests for the diagnostics of a wide variety of malignant epithelial cells in humans. DB-2 contains an immunodominant site of tetanus toxin and a fragment of the locus of the human tumor-associated antigen MUC1 with a variable number of tandem repeats. A pentameric superhelical fragment of the human cartilage oligomeric matrix protein was used as an oligomerization matrix. The expression of the protein in Escherichia coli cells was studied, a method for its purification was developed, and its main biochemical properties were determined. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.

[Design of chimeric proteins based on pentameric superhelical fragments of COMP. I. Properties of a hybrid containing an immunodominant segment of the surface protein of Plasmodium falciparum]. / Konstruirovanie khimernykh belkov na osnove pentamernogo superspiral'nogo fragmenta COMP. I. Svoistva gibrida, soderzhashchego immunodominantnyi uchastok osnovnogo poverkhnostnogo belka plazmodiia Plasmodium falciparum.

The oligomeric recombinant protein DB-1 containing the immunodominant sites of the circumsporozoite protein of Plasmodium falciparum and tetanus toxin was constructed to optimize the schemes of presentation of B-cell epitopes during vaccination with chimeric proteins without the use of adjuvants. A fragment of the pentameric coiled-coil human cartilage oligomeric matrix protein was used as an oligomerization matrix. The expression of the protein in Escherichia coli cells was studied, a method for its purification was developed, and it was biochemically characterized. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.

[Modified oligonucleotides containing 1-beta-D-galactopyranosylthymine: synthesis and substrate properties]. / Modifitsirovannye oligonukleotidy, soderzhashchie 1-beta-D-galaktopiranoziltimin: sintez i substraktnye svoistva.

A convenient method of regioselective introduction of 1-beta-D-galactopyranosylthymine into oligonucleotides was developed and the substrate properties of the modified oligonucleotides were investigated in the enzymic reaction of formation and hydrolysis of internucleotide bonds. The English version of the paper.

[Bacterial synthesis of immunogenic epitopes of foot-and-mouth disease virus fused either to human necrosis factor or to hepatitis B core antigen]. / Bakterial'nyi sintez immunogennykh épitopov virusa iashchura v sostave gibridov s faktorom nekroza opukholei i kor-antigenom virusa gepatita B.

Using recombinant DNA technology, construction and bacterial expression of genes was carried out which code for hybrid proteins, human tumor necrosis factor and hepatitis B core protein fused to immunogenic epitopes of foot-and-mouth disease virus, strains A22 and O1-194. Hybrids of tumor necrosis factor with foot-and-mouth disease antigenic determinants protected laboratory animals against the experimental challenge with a homologous strain of foot-and-mouth disease virus. Hybrid protein that contained immunogenic regions of two strains, A22 and O1-194, protected animals against infection with both A and O serotypes. Hybrid proteins based on hepatitis B virus core antigen retained the ability to assemble into core-like particles.

[Isolation of a group of hybrid proteins consisting of tumor necrosis factor alpha and thymosin alpha 1]. / Poluchenie gruppy gibridnykh belkov, sostoiashchikh iz faktora nekroza opukholei alpha i timozina alpha1.

New plasmid DNA coding for the synthesis of three hybrid proteins differing by the position of alpha 1-thymosin at N- and C-terminals of tumor necrosis factor were optimized and constructed. The instability of plasmids at culturing of E. coli strains stored in solid nutrient media was demonstrated. Newly obtained transformants and preserved cells were cultured, this providing a high level of synthesis of hybrid proteins. The effects of culturing temperature and protein structure on protein solubility were shown. Hybrid proteins were purified by chromatography on hydrophobic anion-exchange carriers and blue agarose in the presence of 7 M urea. After dialysis the proteins displayed different cytotoxicity in L-929 cells and were fit for immunobiological studies.

[Synthesis of an artificial gene coding for thymosin alpha1 and its expression in Escherichia coli as a hybrid with human tumor necrosis factor]. / Sintez iskusstvennogo gena, kodiruiushchego timozin alpha1, i ego ékspressiia v Escherichia coli v sostave gibridov s faktorom nekroza opukholei cheloveka.

Chemical-enzymatic synthesis and cloning in Escherichia coli of an artificial gene encoding the immunoactive peptide thymosin alpha 1 have been carried out. Recombinant plasmids were constructed which contain fusion genes coding for hybrids of human tumour necrosis factor (TNF) and thymosin alpha 1 as N- or C-terminal part of the hybrid protein. In the C-terminal hybrid protein, TNF and thymosin alpha 1 are linked through a methionine residue, thus allowing for thymosin alpha 1 to be cleaved off the rest of the hybrid protein with cyanogen bromide. In case of the N-terminal hybrid protein, the linker between the thymosin alpha 1 and TNF sequences is the acid-labile dipeptide Asp-Pro. Expression of the hybrid genes in E. coli and properties of the recombinant proteins were studied. The N-terminal hybrid protein was secreted into periplasmic space, in contrast with the C-terminal hybrid protein, which formed insoluble aggregates inside bacterial cells. Procedures for the isolation of both hybrid proteins were developed. The N-terminal hybrid protein displayed full biological activity in the cytotoxic assay on the mouse fibroblast L-929 whereas the C-terminal hybrid protein proved to be much less active. Treatment of the hybrid protein TNF-thymosin alpha 1 with cyanogen bromide lead to a mixture of two polypeptides, from which thymosin alpha 1 was purified to homogeneity by simple chromatographic procedures.

[Chemical-enzymatic synthesis and cloning in Escherichia coli of a gene coding for human granulocyte-colony stimulating factor]. / Khimiko-fermentativnyi sintez i klonirovanie v Escherichia coli gena, kodiruiushchego granulotsit-koloniestimuliruiushchii faktor cheloveka.

Two artificial genes, encoding two forms of human granulocyte colony stimulating factor as products of a normal and an alternative splicing, have been by a chemical-enzymatic way synthesized and cloned in Escherichia coli. The genes are supplied with recognition sites of restriction endonucleases to facilitate the further cassette mutagenesis.

[Synthesis, cloning, and expression of artificial genes, coding antigenic determinants of the foot-and-mouth virus substrain A22]. / Sintez, klonirovanie i ékspressiia iskusstvennykh genov, kodiruiushchikh antigennye determinanty virusa iashchura podtipa A22.

Chemical-enzymatic synthesis and cloning in Escherichia coli of double-stranded DNAs, coding for simple and complex antigenic determinants of foot-and-mouth disease virus (FMDV) strain A22, have been carried out. The simple antigenic determinants are a part of the viral coat protein VP1 (amino acid sequence 131-152 or 131-160) whereas the complex antigenic determinants comprise additionally the amino acid sequence 200-213 of VP1 linked to N-terminus of simple antigenic determinants through a tetrapeptide spacer Pro-Pro-Ser-Pro. Recombinant DNAs containing genes for antigenic determinants of FMDV fused with C-terminus of gene for human tumor necrosis factor (hrTNF) have been constructed. Expression of the hybrid genes and properties of the proteins coded were studied. All recombinant proteins were shown to interact specifically with polyclonal antibodies both against hrTNF and FMDV strain A22. The recombinant proteins produced by bacteria are perspective for study as a vaccine against FMDV.