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.

[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.

[Isolation and purification of a protective protein from Propionibacterium freudenreichii subsp. Shermanii]. / Vydelenie i ochistka protektornogo belka iz kletok Propionibacterium freudenreichii substp. Shermanii.

A protein responsible for the protective and reactivating activities of two active fractions (AF1 and AF2) of the cells of Propionibacterium freudenreichii subsp. shermanii was isolated. The active fraction AF1 was obtained by fractional precipitation of the cell-free extract of propionic acid bacteria between 20 and 40% ammonium sulfate saturation, whereas fraction AF2 was precipitated between 60 and 80% saturation. Further fractionation of AF1 and AF2 by gel filtration on Sephacryl S-200 and by ion-exchange chromatography on DEAE-Sepharose yielded seven active subfractions, as revealed by testing for their protective activity on UV-inactivated cells of Escherichia coli. Analysis of subfraction AF2-2.5 by SDS-electrophoresis and HPLC showed that it contained an apparently homogeneous protein with a molecular mass of 44 +/- 2 kDa. The concentrational dependence of the protective activity of this protein was derived. Peptides of subfractions AF2-2.1 and AF2-2.2 with molecular masses lower than 15 kDa also exhibited protective activity.