Specific Antibodies to the Fragments of Meningococcal IgA1 Protease during the Formation of Immunity to Bacterial Infections.

The features of individual fragments of IgA1 protease of Neisseria meningitidis serogroup B during the formation of immunity to bacterial infections in animals and humans were studied. The antibodies to the immunogenic regions of the studied proteins are also detected in mice infected with some bacterial pathogens and in humans with bacterial meningitis. A region of IgA1 protease was identified that is not capable of producing antibodies during immunization of animals, but that detects homologous antibodies in the blood of humans and animals recovered from bacterial infections. It has been suggested that this fragment plays a regulatory role in the process of immunogenesis.

Peculiarities of the Formation of Antimeningococcus Immunity in Mice Immunized with Fragments of N. meningitidis IgA1 Protease.

We studied immunogenicity of two recombinant proteins FR.9 and FR.11-3 created on the basis of fragments of the primary structure of N. meningitidis IgA1 protease with different molecular weights containing different sets of T and B epitopes. The proteins actively protect animals infected with live virulent culture of meningococci, serogroups A, B, and C. Analysis of CD4+, CD8+, and CD19+ lymphocyte populations in mouse blood showed predominant contribution of different cell populations to the formation of immune response to different proteins. Injection of FR.11-3 protein to animals did no affect the immunoregulatory index, hence, this protein can be used for creation of immunologically safe vaccine preparation.

Serological Analysis of Immunogenic Properties of Recombinant Meningococcus IgA1 Protease-Based Proteins.

Using the genome sequence of IgA1 protease of N. meningitidis of serogroup B, four recombinant proteins of different structure and molecular weight were constructed. These proteins were equal in inducing the formation of specific antibodies to IgA1 protease and had protective properties against meningococci. In the sera of immunized mice, anti-IgA1 protease antibodies were detected by whole-cell ELISA, which indicated the presence of IgA1 protease on the surface of these bacteria. We hypothesized that the protective properties of IgA1 protease-based antigens and IgA1 protease analogs could be realized not only via impairment of bacterium adhesion to the mucosa, but also via suppression of this pathogen in the organism. The presented findings seem promising for using these proteins as the basis for anti-meningococcus vaccine.

[Isolation and determination of activity of IgA1 protease from Neisseria meningitidis].

A method of the isolation and purification of IgAl protease from a culture of Neisseria meningitidis serogroup A has been developed. Three inactivated intermediates of the production of the meningococcal vaccine, a culture liquid, as well as a supernatant and sediment obtained by the precipitation of bacterial cells by cetavlon, served as a starting material. The purity of IgA1 protease was determined by SDS-PAGE. An immunoenzyme assay for determining the IgA1 protease activity has been devised. The yield of the enzyme with a specific activity of 0.5 to 4 million units/mg from 103 g of the cetavlon precipitate (40 l of culture liquid) was about 600 mug. It was shown that IgAl protease isolated from serogroup A meningococcus is capable of protecting experimental animals (mice) infected with meningococcus of serogroup B.

Action of influenza virus neuraminidase on gangliosides. Haemagglutinin inhibits viral neuraminidase.

The action of partly purified neuraminidase (NA) of influenza A virus, a mixture of detergent solubilized NA and haemagglutinin (HA) and of intact virions on gangliosides GT1b, GD1a, GD1b, GM1 was studied. The viral NA transformed GT1b mainly into GD1b with formation of only minor amounts of GM1. HA was found to inhibit the hydrolysis activity of viral NA. At the same time viral NA transformed GD1a quantitatively into GM1 which was not hydrolyzed by the enzyme. These results suggest that the function of NA is to transfer the 'primary' receptor (such as GT1b) into the proper carbohydrate sequence (GD1b-like) which is proposed to serve as the minimal structure required for influenza virus reception.

Chemical studies on actinoxanthin.

The antitumor protein actinoxanthin exhibits high inhibitory activity against a number of gram-positive bacteria and some strains of transplantable leucoses and related tumors. Actinoxanthin was shown to consist of a single polypeptide chain crosslinked by two disulfide bonds and to contain 107 amino acid residues. Reduced and alkylated actinoxanthin was digested with chymotrypsin, thermolysin and trypsin. Based on the sequence analysis of fragments so obtained the complete amino acid sequence and the location of disulfide bonds of actinoxanthin has been proposed. The high degree homology of some regions of actinoxanthin and the antitumor protein neocarzinostatin have been revealed.

Monoclonal antibodies directed to the synthetic carbohydrate antigen Ley.

Tetrasaccharide Fuc alpha 1-2Gal beta 1-4(Fuc alpha 1-3)GlcNAc is known as carbohydrate determinant of cancer- and AIDS-associated antigen Lewisy (Ley). Synthetic antigen to generate mouse monoclonal antibodies (MAbs) directed to Ley was prepared and constructed as a spacer-armed tetrasaccharide coupled with lipophilized polymer, Ley-PAA-PE, where PAA is a 30-kD polyacrylamide and PE is phosphatidylethanolamine. An efficient immune response was provided by using Ley-PAA-PE adsorbed on Salmonella minnesota. Positive hybridomas were screened by enzyme-linked immunosorbent assay (ELISA) using Ley-PAA as a coating agent. An inhibitory version of the same test system showed absolute specificity of two MAbs: only hapten Ley and Ley-PAA were strong inhibitors, in contrast to Leb, tri- and disaccharidic fragments of the mentioned tetrasaccharides, as well as their PAA-conjugates. MAbs obtained against synthetic antigen specifically stained the Ley (+) cell line A431.

[Isolation and characteristics of galactose-binding lectins from human blood serum]. / Vydelenie i kharakteristika galaktozosviazyvaiushchikh lektinov iz syvorotki krovi cheloveka.

Two galactose-binding lectins, SL1 and SL2, were isolated from human serum by two-step affinity chromatography on sorbents with immobilized disaccharides Gal beta 1-3GlcNAc beta (Lec) and Fuc alpha 1-2Gal beta (Hdi). The purification degree of the SL1 and SL2 preparations was 4000-6000 times and yields were 6.9 and 4.7 micrograms/ml of serum, respectively. Electrophoresis showed that both lectins are oligomers with molecular masses of about 440 kDa, which are composed of ca. 67 kDa subunits. The carbohydrate specificity of the lectins was assayed by hemagglutination inhibition using mono- and oligosaccharides. Both lectins showed specificity for Gal and GalNAc residues but differed in the interactions with oligosaccharides. In particular, SL1 showed maximum affinity for disaccharide Gal beta 1-3GalNAc beta (in the form of 4-nitrophenyl glycoside), 6'-sialyllactose, and disaccharide residues Fuc alpha 1-3Gal beta and Gal alpha 1-3Gal beta, whereas SL2 was specific for GalNAc alpha residue and its derivatives as well as for disaccharide Hdi.

[Sialylation of N-carbohydrate chains of glycoproteins with immobilized trans-sialidase from Trypanosoma cruzi]. / Sialilirovanie N-uglevodnykh tsepei glikoproteinov s pomoshch'iu immobilizovannoi trans-sialidazy Trypanosoma cruzi.

Alpha2,3-sialylation of the lactosamine type N-glycans with trans-sialidase from Trypanosoma cruzi is reported. Trans-sialidase (160 kDa, pI 5.35-5.65) and its catalytic fragment (70 kDa, pI 6.0-6.3) were isolated from T. cruzi cells and immobilized on ConA-Sepharose. The resulting preparation retained activity for several months and was repeatedly used for obtaining mono-, di-, tri-, and tetrasialylated 7-amino-4-metylcoumarine-labeled oligosaccharides with various numbers of antennas and for alpha2,3-sialylation of glycans within glycoproteins and neoglycoconjugates.

[A composite polyaniline-containing silica sorbent for DNA isolation]. / Kompozitsionnyi polianilinsoderzhashchii kremnezemnyi sorbent dlia vydeleniia DNK.

A composite sorbent based on porous glass beads modified with thin polyaniline coating was prepared by precipitating aniline polymerization in the presence of carrier particles. It was shown that the modification ensures the uniform coating of the inner surface of the carrier pores with the polymer layer approximately 70 A thick. It was shown that the resulting material retains the initial porosity of the carrier and is selective in the separation of nucleic acids and proteins. The polyaniline-coated sorbents were shown to be efficient for both the preparative DNA isolation from bacterial lysates and for analytical purposes, in particular, for studying DNA fragmentation during apoptosis proceeding under UV irradiation of cell lysates of colon carcinoma. The morphological and chromatographic characteristics of the new sorbent were demonstrated to be similar to those of the polyfluorobutadiene sorbent.

[Molecular design of polymeric materials for biotechnology and medicine]. / Molekuliarnoe konstruirovanie polimernykh materialov dlia biotekhnologii i meditsiny.

This review describes new polymer materials for biomedical applications developed in the Polymers for Biology Laboratory of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences. These include composite rigid sorbents for biochromatography, polymer dispersions for immunoassay, polymer hydrogels for immobilization of enzymes and cells, and polymer ultra thin films as biomembrane models and materials for biosensors. Some general and specific properties of these new materials and models as well as examples of their applications are discussed.

[Use of the zwitterion detergent Sulfobetain-12 for preparation of virosomes and investigation of their immunogenic and protective properties]. / Ispol'zovanie tsvitterionnogo detergenta sul'fobetaina-12 dlia polucheniia virosom i izuchenie ikh immunogennykh i protektivnykh svoistv.

Virosomes were prepared by using the zwitterion detergent sulfobetaine-12. The virosomes included the surface antigens and virus-specific lipids of influenza virus, strain A/PR/8/34. Immunogenic and protective properties of the surface antigens in the micellar form and as a complex with the virosomes were studied. The surface antigens of this complex, like the intact virus, were found to possess the high immunogenic and protective activity in relation to the following infection with the homologous pathogenic virus.

[Polymer-modified silica sorbents for molecular sieve chromatography of biopolymers]. / Polimerno-modifitsirovannye kremnezemnye sorbenty dlia molekuliarno-sitovoi khromatografii biopolimerov.

N-vinylpyrrolidone-N(2-hydroxy) acrylamide copolymer-modified porous glass was studied as a support for gel permeation chromatography. Influenza, Sendai, fowl plague viruses and rota-viruses were purified by chromatography on the support. As compared with Sepharose 4B the support shows better hydrodynamic properties and yields higher amounts of purified viruses. The support can be also applied to the t-RNA and ribosomes separation.

[Protective properties of recombinant IgA1 protease from meningococcus].

The study of enzymatic and protective properties of recombinant IgA1 protease in active and mutant form showed that active form of IgA1 protease exhibited species - and type-specificity for mouse and human immunoglobulins. Mutant form, which did not exhibit enzymatic activity, had protective properties against meningococcal infection, induced by meningococcus serogroup A, B and C protecting the mice from lethal infection by living virulent culture of heterologous serogroups of meningococcus. Obtained results make it possible to consider IgA1 protease as a perspective preparation at the stages of development of polyvalent vaccine for protection the people from meningococcal infection of various etiology.

Purification of monoclonal antibodies to Le(y) and Le(d) carbohydrate antigens by ion-exchange and thiophilic-adsorption chromatography.

The paper deals with convenient and fast methods for purification of monoclonal antibodies (MAbs) to carbohydrate antigens Le(y) and Le(d) from the cell culture and ascite fluid by ion-exchange chromatography on S-Sepharose and salt-promoted chromatography on a "thiophilic" adsorbent. One-step procedure on S-Sepharose of MAbs to Le(y) (IgG and IgM) provides significant purification (over 90% of contaminants were removed), while a purification factor for IgM to Le(d) is much lower. Highly purified IgM to Le(d) could be obtained by a two-step purification procedure including "thiophilic-adsorption" chromatography and gel-filtration (90-98% of contaminants from the cell culture and ascite fluid were removed). The preparations of IgG and IgM retain their initial antibody activity.

Characterization of weak hydrophobic composite sorbents and their application to the isolation of bacterial lectin.

Composite sorbents based on wide-pore glass and silica coated with N-butyl polyacrylamide (butyl-PA-glass and butyl-PA-silica) were studied. The surface tension of butyl-PA-silica is 50-55 mJ/m2 as evaluated by the sedimentation volume technique. The linear dependences of log k' on ammonium sulphate concentration were determined by isocratic chromatography of the dipetide Trp-Trp and lysozyme on butyl-PA-glass. Both solutes were shown to have a weaker retention on butyl-PA-glass than on butyl-Toyopearl 650C. This weaker retention is beneficial in the purification of sialic acid-binding lectin from Bacillus subtilis.

Cellular localization of the galactose-binding lectin from human serum.

An SL2 lectin was isolated from human serum and characterized previously; cellular localization of the lectin was studied using polyclonal rabbit antibodies. According to cytofluorimetry, anti-SL2 antibodies bound only to lymphocytes and monocytes but not to other blood cells. Antibodies bound to Jurkat T cell lymphoma but did not interact with IM-9 cells of B cell origin. Moreover, the Jurkat cells bound oligosaccharides having the highest affinity to SL2 (GalNAcalpha_and Fucalpha1-2Gal), and this interaction was inhibited by anti-SL2 antibodies. Lysis of the Jurkat cells with subsequent electrophoresis and Western blotting indicates that anti-SL2 antibodies recognized a 14-kD protein.