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

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.

No abstract

The proposed method is economical and reliable and can be used for evaluation of IgA1 and IgA2 in clinical laboratories or for research purposes.

The immunogenic and protective activities of recombinant IgA1 serine protease obtained on the base of the genome DNA of N. meningitidis serogroup B strain H44/76 were studied. A several recombinant proteins of different molecular weights that are based on the full-length primary structure of the enzyme, taking into account the distribution of B- and T-epitopes, also were studied. In experiments on laboratory animals it was shown that a number of tested preparations demonstrate the immunogenic and protective activity to protect mice from lethal challenge with virulent strains of meningococcus serogroups A, B and C, thereby exhibiting polyvaccine properties. The protective role of antibodies against the IgA1 protease was shown when mice were infected by meningococccus serogroup B. The increase in antibodies to the meningococcal IgA1 protease into the blood of rabbits infected with different serotypes of pneumococci has been detected, indicating potential ability of the meningococcal IgA1 protease to generate protection against microbes the virulence of which is caused by IgA1protease.