Comparative genomic and surface proteomic analysis of three Bordetella pertussis strains used in vaccine production

BOTTERO D.; GAILLARD ME., BINSZTEIN N. AND HOZBOR D; FERNÁNDEZ J.; WELTMAN G,; REGUEIRA M.; BINSZTEIN N.; HOZBOR D.

Paris

Simposio; Eighth International Symposium: Saga of the Genus Bordetella, 1906 - 2006; 2006

Institut Pasteur

Until few years ago Bordetella pertussis was considered as a clonal population, however, recent studies demonstrated the existence of divergence among circulating bacterial population. The extent of this divergence was not fully characterized yet. New tools like genomics and proteomics bring the possibility to assess the whole divergence at molecular level. With this goal we initiated these kind of studies on three known B. pertussis strains widely used for vaccine production. The degree of genotypic similarity among the strains was examined by PFGE. The relatedness for the DNA PFGE-profiles obtained after XbaI restriction were calculated by UPGMA clustering of Dice coefficients, using the BioNumerics software. The analysis discriminated two PFGE profiles groups: I–II. The profiles corresponding to the vaccine strains Tohama I and 10536 (group I) had a relatedness of 62,5% with the strain 509 (group II). The level of relatedness was 71,5% for group II. In order to analyse if this genomic differences correlate with the proteome of each strain, we compared the bacterial surface proteomes since surface proteins are likely to interact with the host immune system. We separated membrane from cytoplasmic fraction and then proteins identification was performed by 2D–electrophoresis coupled to mass spectrometry. Approximately 70 different spots were observed in the 2D of the three strains, from which at least four proteins are expressed differentially. Probable surface antigen and Bp1440 outer membrane protein were expressed in Tohama and 509 strains and Bp2626 and Bp2916 were only expressed in Tohama. All these results demonstrated a correlation between genomic divergence and protemics and suggest the possibility to find novel vaccine candidates.