Comparative proteomic analysis of Australian epidemic Bordetella pertussis

Bordetella pertussis causes whooping cough, a re-emerging vaccine preventable disease. Pathogen adaptation is an important factor for re-emergence. Since acellular vaccine (ACV) introduction, the predominant strains changed to single nucleotide polymorphism (SNP) cluster I (ptxP3/prn2) from cluster II (ptxP1/prn3). An in vivo mixed infection in mouse showed that cluster I were fitter than cluster II regardless of the host’s immunisation background. Proteomic methods for secretome and surfaceome analysis was established. The B. pertussis secretome was characterised in Stainer-Scholte (SS) and Thalen-IJessel (THIJS) media. Ten virulence proteins were detected uniquely in THIJS while an additional 7 showed trends of upregulation. No virulence proteins were upregulated in SS. THIJS was found to promote virulence factor secretion and is more suitable for studying the secretome. For surfaceome, optimal surface shaving of B. pertussis was performed with 1 µg of trypsin for 5 min. Flow cytometry demonstrated minimal cell lysis after shaving. The whole cell, secretome and surfaceome of L1423 (cluster I) and L1191 (cluster II) in THIJS were compared using the methods established to determine proteomic differences that play a role in increased fitness. No differences were observed in ACV antigen expression. However, downregulation of a TLR2 agonist and type III secretion system (T3SS) effectors was consistently observed in L1423. An upregulation of TcfA and transport proteins for metals, phosphates and amino acids were also observed. These differences may affect immune evasion, virulence and metabolism, and result in increased fitness of cluster I. The expression differences between L1423 and L1191 were also compared under sulphate. Sulphate is an important modulator of virulence expression and is released during infection from damaged cells which alters virulence. Expression differences identified under sulphate were also observed when sulphate was absent including increased TcfA and decreased T3SS effectors. No additional expression differences were observed when sulphate was present suggesting that sulphate is not a factor for adaptation. Finally, 11 housekeeping proteins were identified in every proteome. These proteins are immunogenic, contain essential functions and forms the basis for further research into novel antigens. Together, these findings provide greater understanding of pathogen adaptation that can be used to prevent re-emergence.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2018

Author dc:creator

• Luu, Laurence

• Proteomics
• Bordetella pertussis
• Whooping cough
• Secretome
• Surfaceome
• Evolution
• Vaccine

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/3534

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/60463