Crohn's disease-specific pancreatic autoantibodies are specifically present in ruminants with paratuberculosis: implications for the pathogenesis of the human disease

Autoimmunity. 2013 Sep;46(6):388-94. doi: 10.3109/08916934.2013.786047. Epub 2013 May 2.

Abstract

Mycobacterium avium subspecies paratuberculosis (MAP) induces paratuberculosis (ptb) in ruminants and has clinical and histological features resebling Crohn's disease (CD). Pancreatic autoantibodies (PAB) targeting glycoprotein 2 (GP2) are specifically found in CD, but it is currently unknown whether these autoantibodies can be found in ruminants with ptb. IgG anti-MAP and anti-GP2 antibodies were tested by ELISA in 286 ruminants (212 sheep and 74 cattle). PAB testing was performed by indirect immunofluorescence (IIF) using anti-sheep or anti-cattle specific antisera. PCR analysis confirmed the presence of MAP in anti-MAP positive samples. Anti-GP2 antibodies were more prevalent in anti-MAP antibody positive (26.9%) than in anti-MAP negative ruminants (8.7%, p < 0.001). Anti-GP2 antibodies were found in 16/70 (22.9%) anti-MAP positive sheep compared to 10/142 (7%, p = 0.001) anti-MAP antibody negative and in anti-MAP positive cattle than in negative counterparts (5/8 versus 8/66, p = 0.003). Absorbance values for anti-GP2 antibodies were higher in cattle than in sheep (mean 21 AU/mL ± 25.4SD versus 12.2 AU/mL ± 23 SD, p < 0.001). There was no correlation between anti-GP2 and anti-MAP antibody concentrations. Anti-GP2 antibodies persisted up to 1/1000 and showed the characteristic IIF pancreatic pattern seen by anti-GP2 antibody positive CD samples. This is the first study to demonstrate the presence of CD-specific GP2-reactive pancreatic autoantibodies in MAP-infected ruminants. Our data suggest that CD and ptb are characterised by an antigen-driven loss of immunological tolerance to GP2, implying commonalities in the immunopathogenesis of the human and ruminant inflammatory bowel disorder.

MeSH terms

  • Animals
  • Antibodies, Bacterial / immunology
  • Antibody Specificity / immunology*
  • Autoantibodies / blood
  • Autoantibodies / immunology*
  • Cattle
  • Crohn Disease / immunology*
  • GPI-Linked Proteins / immunology
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Mycobacterium avium subsp. paratuberculosis / immunology
  • Pancreas / immunology*
  • Paratuberculosis / immunology*
  • Ruminants
  • Seroepidemiologic Studies
  • Sheep

Substances

  • Antibodies, Bacterial
  • Autoantibodies
  • GP2 protein, human
  • GPI-Linked Proteins
  • Immunoglobulin G