title: Proteomic characterization of a natural host-pathogen interaction: repertoire of in vivo expressed bacterial and host surface-associated proteins.
abstract: Interactions between a host and a bacterial pathogen are mediated by cross-talk between molecules present on, or secreted by, pathogens and host binding-molecules. Identifying proteins involved at this interface would provide substantial insights into this interaction. Although numerous studies have examined in vitro models of infection at the level of transcriptional change and proteomic profiling, there is virtually no information available on naturally occurring host-pathogen interactions in vivo. We employed membrane shaving to identify peptide fragments cleaved from surface-expressed bacterial proteins and also detected proteins originating from the infected host. We optimized this technique for media-cultured Corynebacterium pseudotuberculosis, a sheep pathogen, revealing a set of 247 surface proteins. We then studied a natural host-pathogen interaction by performing membrane shaving on C. pseudotuberculosis harvested directly from naturally infected sheep lymph nodes. Thirty-one bacterial surface proteins were identified, including 13 not identified in culture media, suggesting that a different surface protein repertoire is expressed in this hostile environment. Forty-nine host proteins were identified, including immune mediators and antimicrobial peptides such as cathelicidin. This novel application of proteolytic shaving has documented sets of host and pathogen proteins present at the bacterial surface in an infection of the native host.
authors.affiliation: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, ‡Department of Microbiology, §Department of Biochemistry and Molecular Biology, Monash University , Clayton, Victoria 3800, Australia.
authors.forename: Megan A
authors.initials: MA
authors.lastname: Rees
authors.forename: Oded
authors.initials: O
authors.lastname: Kleifeld
authors.forename: Paul K
authors.initials: PK
authors.lastname: Crellin
authors.forename: Bosco
authors.initials: B
authors.lastname: Ho
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Stinear
authors.forename: A Ian
authors.initials: AI
authors.lastname: Smith
authors.forename: Ross L
authors.initials: RL
authors.lastname: Coppel
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D003354:Corynebacterium Infections / Q000378:metabolism / Q000382:microbiology / Q000662:veterinary*; D016925:Corynebacterium pseudotuberculosis / Q000502:physiology*; D054884:Host-Pathogen Interactions; D008198:Lymph Nodes / Q000382:microbiology; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D012756:Sheep / Q000378:metabolism* / Q000382:microbiology; D012757:Sheep Diseases; D034561:Sheep, Domestic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D020543:Proteome
keywords: Corynebacterium pseudotuberculosis; Mycobacterium; Proteomics; surface proteins