[ODP6B] b. Toxins, Effectors, and Bioactive Substances

[ODP-132] Virulence factors in membrane vesicle of Bordetella pertussis planktonic and biofilm cultures

○Tomoko Hanawa¹, Kazunari Kamachi², Asaomi Kuwae³, Akio Abe³, Hideo Yonezawa¹, Takako Osaki¹, Fuhito Hojo⁴, Shigeru Kamiya¹, Jiro Mitobe¹ (¹Dept of Infect. Dis. Sch. Med., Kyorin Univ., ²Dept. Bac. II Natl Inst. of Infec. Dis., ³Lab. Bact. Infect., Grad. Sch. Infect. Cont. Sci., Kitasato Univ., ⁴Facit., Kyorin Univ. Sch. Med.)

Background and Objective: Efficacy of the pertussis vaccine is diminishing from approximately 10 years after vaccination, and the strains escaping from vaccine pressure have emerged. Therefore, it is necessary to develop new vaccine. Membrane vesicles (MVs) are vesicles with a diameter of 10-400 μm that are released by bacteria, and are possible candidate for vaccine component. However, spontaneously secreting MVs have not been sufficiently investigated. In this study, we conducted a proteomic analysis to compare the proteins in MVs secreted from planktonic and biofilm-forming bacteria.
Materials and Methods: MVs were collected by ultracentrifugation of the filtered culture supernatant of B. pertussis. After purification by OptiPrep density gradient centrifugation, MVs were analyzed by Nano LC-MS/MS using Proteome Discoverer 2.4 (Thermo Fisher Scientific).
Results and Discussion: Complement inhibitors such as Vag8 and BrkA were found in MVs derived from both planktonic bacteria and biofilm. Virulence associated factors, FimB and BopD, were specifically detected in the MVs from planktonic bacteria. On the other hand, filamentous hemagglutinin, adenylate cyclase toxin, FhaS and SphB1 were abundant in biofilm-derived MVs. These virulence associated factors are relating to adhesion and colonization. Accordingly, biofilm-derived MVs probably have some roles in the colonization.