Identification of two Mycobacterium avium subspecies paratuberculosis gene products differentially recognised by sera from rabbits immunised with live mycobacteria but not heat-killed mycobacteria

J Med Microbiol. 2001 Sep;50(9):795-804. doi: 10.1099/0022-1317-50-9-795.


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.

MeSH terms

  • Animals
  • Antigens, Bacterial / analysis*
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / immunology
  • Cattle
  • Cells, Cultured
  • Immune Sera / immunology*
  • Immunoblotting
  • Macrophages / immunology
  • Macrophages / microbiology
  • Mice
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / immunology
  • Mycobacterium avium subsp. paratuberculosis / genetics
  • Mycobacterium avium subsp. paratuberculosis / immunology*
  • Open Reading Frames
  • Rabbits
  • Sequence Analysis, DNA


  • Antigens, Bacterial
  • Bacterial Proteins
  • Immune Sera
  • Multienzyme Complexes
  • PS1 protein, Corynebacterium glutamicum