title: Identification of two Mycobacterium avium subspecies paratuberculosis gene products differentially recognised by sera from rabbits immunised with live mycobacteria but not heat-killed mycobacteria.
abstract: The investigation of environmentally regulated proteins has led to a better understanding of host-pathogen interactions and identified novel vaccine candidate antigens for several bacterial pathogens. In an effort to identify such proteins in Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), a genomic expression library was differentially screened with sera from rabbits that had been immunised with live M. paratuberculosis (alpha-live) as well as sera from rabbits immunised with heat-killed M. paratuberculosis (alpha-killed). These experiments identified seven recombinant plaques that were uniquely recognised by the alpha-live sera. Sequence data showed that five of these clones overlapped with each other and contained a common open-reading frame encoding a 25-kDa protein, termed Csp1. The 25-kDa antigen shows weak similarity to a secreted Corynebacterium glutamicum protein. The remaining two clones overlapped with each other and contained two partial open-reading frames, both encoding proteins with strong homology to polyketide synthase from various species of mycobacteria. Antisera were produced against a peptide of the polyketide synthase gene product designated Pks7. Csp1-specific antibodies were affinity purified from the alpha-live sera. These purified antibodies demonstrated that Csp1 was present within infected macrophages. Collectively, these data identify novel M. paratuberculosis antigens that may be important in pathogenesis.
authors.affiliation: National Animal Disease Center, ARS-USDA, Ames, IA 50010, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Bannantine
authors.forename: Judith R
authors.initials: JR
authors.lastname: Stabel
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D002417:Cattle; D002478:Cells, Cultured; D007106:Immune Sera / Q000276:immunology*; D015151:Immunoblotting; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D009097:Multienzyme Complexes / Q000235:genetics / Q000276:immunology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology*; D016366:Open Reading Frames; D011817:Rabbits; D017422:Sequence Analysis, DNA
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007106:Immune Sera; D009097:Multienzyme Complexes; C077000:PS1 protein, Corynebacterium glutamicum