A novel Lawsonia intracellularis autotransporter protein is a prominent antigen

Eleanor Watson, Ewan M. Clark, M. Pilar Alberdi, Neil F. Inglis, Megan E. Porter, Lisa Imrie, Kevin McLean, Erin D. T. Manson, Alex F. Lainson, David George Emslie Smith

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)


    Investigation of antigenic determinants of the microaerophilic obligate intracellular bacterium Lawsonia intracellularis using a mass spectrometry approach identified a novel bacterial protein present in an extract of cell culture medium aspirated from heavily infected in vitro cell cultures. Western immunoblotting analysis of SDS-PAGE-resolved proteins using immune sera pooled from L. intracellularis-infected pigs revealed the presence of a strongly immunoreactive band of ∼ 72 kDa. Liquid chromatography-electrospray ionization-tandem mass spectrometry analysis of this component and database mining using a fully annotated L. intracellularis genome sequence and the comprehensive GenBank prokaryotic genomic database highlighted the presence of a protein that shares little sequence similarity with other prokaryotic proteins and appears to be highly species specific. Detailed bioinformatic analyses identified the protein as member of the autotransporter protein family of surface-exposed proteins, and the designation LatA (Lawsonia autotransporter protein A) is suggested. Recognition of recombinant LatA on Western blots by a panel of sera from infected and control pigs corresponded 100% with a commercial serodiagnostic that relies on in vitro culture of this fastidious organism. LatA therefore represents a potential candidate for the development of a rapid and species-specific serodiagnostic reagent.

    Original languageEnglish
    Pages (from-to)1282-1287
    Number of pages6
    JournalClinical and Vaccine Immunology
    Issue number8
    Publication statusPublished - Aug 2011


    • Animals
    • Antibodies, Bacterial
    • Antigens, Bacterial
    • Blotting, Western
    • Computational Biology
    • Desulfovibrionaceae Infections
    • Immunoassay
    • Lawsonia Bacteria
    • Mass Spectrometry
    • Membrane Transport Proteins
    • Swine


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