Characterization of the Outer membrane vesicles (OMVs) obtain from Bordetella pertussis

Introduction and Objectives: Pertussis is a respiratory infectious disease that has been resurged during the last two decades despite high vaccine coverage worldwide. The increase in pertussis cases has been mostly attributed to waning vaccine-induced immunity, the switch from whole cell vaccines to acellular vaccines (aP) and pathogen adaptation in the face of the selection pressure induced by the vaccine that results in changes in the B. pertussis bacterial population strains that do not have a perfect match with the vaccine. The epidemiological situation of pertussis points out the need to develop new generation of vaccines that capable of conferring both long-lasting immunity and protection against different strain genotype in this regard we characterize the properties of OMVs obtained from Bordetella pertussis as a good vaccine candidate.Material and Methods: The isolate of B. pertussis was grown at 36 ◦C for 72 h on Bordet Gengou agar (BGA) supplemented with 10% defibrinated sheep blood, and subcultured 24 h in the same medium before use. The OMVs obtained from Bordetella pertussis strain were negatively stained and examined with an electron microscope.SDS-PAGE, immunoblot techniques were used to describe OMVs properties. Results: the size range of OMV was consistent from batch to batch and similar to previously described OMV preparations. To further characterize the OMVs immunoblottings were performed using specific antibodies against Ptx and Prn and Fha. OMVs studied expressed all three main protective immunogen. Conclusion: Altogether according to the results OMVs derived from B. pertussis express 3 virulence factors, it is tempting to speculate that protective efficacy observed with all OMVs may be attributed to common factors that are expressed in all bacterial strains used. since OMVs reported here contain main immunogens used in currently acellular vaccines but expressed in the context of the pertussis membrane, allowing the immune response to preferentially target surface-exposed epitopes in their native conformation it might be considered a possible basic material for the development of acellular pertussis vaccines.

Keywords:

Bordetella pertussis , outer membrane vesicles , Vaccine candidate