[Immunogenic and protective characteristics of surface antigens 6 and d of Burkholderia pseudomallei].

AIM: Extraction of complex of Burkholderia pseudomallei antigens 6+d (Ag6+d) and study of its immunogenic and protective characteristics. MATERIALS AND METHODS: Studied antigens were obtained from acrtone-dried cells of B. pseudomallei 57576. Experiments were performed on white mouse model. Microbiological, immunochemical as well as immunological methods were used in the study. RESULTS: It was shown that antigenic complex 6+d has a glycoprotein nature and corresponds to high-polymeric catode-moving antigen 6 with molecular mass 500 kDa and anode-moving antigen d with molecular mass 40 - 55 kDa. Immunogenic and protective characteristics of surface antigenic complex 6+d was studied. It was noted that Ag6+d caused reliable stimulating effect on cellular arm of immune system of white mice appeared in activation of delayed-type hypersensitivity reactions, enhanced phagocytic activity of polymorphonuclear macrophages as well as increased expression of Fc-receptors on macrophages and neutrophils. CONCLUSION: Observed stimulation of cellular immunity by surface antigens was confirmed during study of their protective characteristics on the model of experimental meloidosis in white mice.

[Comparative assessment of DNA extraction methods for identification of glanders and melioidosis etiological agents by PCR].

Pathogenic Burkholderia are considered as a cause of dangerous infections and potential agents of bioterrorism. Comparative assessment of different methods of extraction and purification of DNA for PCR analysis of pure cultures and samples contaminated by etiological agents of glanders and melioidosis was performed. Samples of soil and food artificially contaminated by pathogenic Burkholderia as well as organs of infected animals were tested. DNA was extracted by methods of boiling, nucleosorption with presence of guanidine thiocyanate, guanidine thiocyanatephenol extraction, guanidine thiocyanate-phenol extraction with additional purification of DNA by nucleosorption. Amplification was performed by "Flash" technique and detector of fluorescence was used for analysis of PCR products. Utilization of the recommended methods of preparation depending on the nature of sample let to detect by the "Flash" technique the etiological agents of glanders and melioidosis in concentration =10(3) microbial cells per ml. Choice of DNA extraction and purification methods is determined by type of a sample and presence in it of admixtures inhibiting PCR.

[Phagocytosis of Burkholderia mallei as a criterion for immunogenicity evaluation of its capsular antigens].

Test-system using index of phagocytosis of noncapsulated mutant loaded by one of the several capsular antigenic complexes was developed and used for screening for both immunogenic and protective capsular antigens of B. mallei. Direct correlation between index of phagocytosis, level of delayed-type hypersensivity, and protective effect of capsular antigens has been shown on the model of experimental melioidosis in susceptible white mice, guinea pigs and white rats. Obtained results let to use the developed test-system for initial selection of B. mallei protective capsular antigens and their further study as potential components of preparations for specific prophylaxis of glanders and melioidosis.

[Immunogenicity of surface and capsular antigens of Burkholderia].

Study showed that five (C3, C6, C9, C10, C11) out of ten chromatographic fractions of surface and capsular antigens of B. mallei significantly stimulated cell-mediated immunity that manifested in activation of delayed hypersensivity reactions (DHS) and phagocyteability of noncapsulated avirulent strain of B. mallei with added surface and capsular antigenic complexes. Other fractions did not stimulate cell-mediated immunity, furthermore, fraction C8, which contained capsular biopolymer with mass of 200 kD (Ar8), was characterized by immunosuppressive effect on DHS and phagocytosis. Observed stimulation of cell-mediated immunity by fractions referred above has been confirmed by assessment of their protective effects on the model of experimental melioidosis in white rats. Relationship between markers of humoral and cell-mediated immunity, including markers of specific response, was not observed.

[Some properties of plasmocoagulase of the causative agents of glanders and melioidosis].

Criteria for the evaluation of the plasmocoagulase activity of natural isolates and mutant strains of the causative agents of glanders and melioidosis were worked out, which made it possible to subdivide them by this sign into pathogens with high, moderate and low activity. Plasmocoagulase produced by pathogenic Burkholderia was shown to be a thermolabile enzyme, comparatively stable with respect to the action of such chemico-biological agents as hydrogen peroxide and chloramine.