Proteomic Analysis of Iron stressed Bordetella pertussis. A search for new vaccine Candidates.

PEREZ VIDAKOVICS, M. LAURA; PABA MARTINEZ, JAIME; LAMBERTI, YANINA; RICART, CARLOS ANDRÉ ; DEL VALLE SOUSA, MARCELO ; RODRIGUEZ, MARÍA EUGENIA

Pasteur Institute, Paris, Francia.

Simposio; 8th International Symposium: Saga of the Genus Bordetella., 1906-2006; 2006

>Regulation of gene expression in response to local iron concentration is commonly observed in bacterial pathogens. In previous studies we found B. pertussis response to iron limitation to encompass an increase in virulence and immunogenicity. In this study, the proteomic approach was used to analyze the differential protein expression of B. pertussis under iron limitation. Whole cell lysates (WCL) and outer membrane fractions (OMF) of bacteria grown either under iron-starvation or iron-excess conditions were analyzed by two-dimensional gel electrophoresis(pH 4-7; SDS-PAGE 10%). The resulting average protein maps of WCL and OMF contained 900 and 240 spots, respectively. Statistical analysis of spot volume in paired spots revealed 20 proteins displaying differential expression, 2 with higher expression under iron-excess and 18 with increased expression under iron-starvation. These proteins were subjected to tryptic digestion and MALDI-TOF-MS. Apart from those previously reported we identified new low-iron induced proteins that might help to explain the increased virulence of this phenotype. Additionally, we found evidence that at least one of the identified OMF, solely expressed under iron starvation, is immunogenic in infected individuals. Further studies are being conducted to gain a better insight into their role in bacterial pathogenesis and their potential as vaccine components.