title: Francisella tularensis LVS surface and membrane proteins as targets of effective post-exposure immunization for tularemia.
abstract: Francisella tularensis causes disease (tularemia) in a large number of mammals, including man. We previously demonstrated enhanced efficacy of conventional antibiotic therapy for tularemia by postexposure passive transfer of immune sera developed against a F. tularensis LVS membrane protein fraction (MPF). However, the protein composition of this immunogenic fraction was not defined. Proteomic approaches were applied to define the protein composition and identify the immunogens of MPF. MPF consisted of at least 299 proteins and 2-D Western blot analyses using sera from MPF-immunized and F. tularensis LVS-vaccinated mice coupled to liquid chromatography-tandem mass spectrometry identified 24 immunoreactive protein spots containing 45 proteins. A reverse vaccinology approach that applied labeling of F. tularensis LVS surface proteins and bioinformatics was used to reduce the complexity of potential target immunogens. Bioinformatics analyses of the immunoreactive proteins reduced the number of immunogen targets to 32. Direct surface labeling of F. tularensis LVS resulted in the identification of 31 surface proteins. However, only 13 of these were reactive with MPF and/or F. tularensis LVS immune sera. Collectively, this use of orthogonal proteomic approaches reduced the complexity of potential immunogens in MPF by 96% and allowed for prioritization of target immunogens for antibody-based immunotherapies against tularemia.
authors.affiliation: Rocky Mountain Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research, Department of Microbiology, Immunology, and Pathology, Colorado State University , Campus Delivery 0922, Fort Collins 80523, Colorado, United States.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Chandler
authors.forename: Marjorie D
authors.initials: MD
authors.lastname: Sutherland
authors.forename: Marisa R
authors.initials: MR
authors.lastname: Harton
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Molins
authors.forename: Rebecca V
authors.initials: RV
authors.lastname: Anderson
authors.forename: Darragh G
authors.initials: DG
authors.lastname: Heaslip
authors.forename: Catharine M
authors.initials: CM
authors.lastname: Bosio
authors.forename: John T
authors.initials: JT
authors.lastname: Belisle
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D001428:Bacterial Vaccines / Q000627:therapeutic use*; D002853:Chromatography, Liquid; D005604:Francisella tularensis / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D000090204:Mesothelin; D051379:Mice; D056990:Post-Exposure Prophylaxis; D053719:Tandem Mass Spectrometry; D014406:Tularemia / Q000517:prevention & control*
chemical_list: D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D008565:Membrane Proteins; C000715528:Msln protein, mouse; D000090204:Mesothelin
keywords: Francisella tularensis; adaptive immunity; antibodies; membrane proteome; surface proteome