Acute phase protein response in an experimental model of ovine caseous lymphadenitis

Abstract

Abstract Background Caseous lymphadenitis (CLA) is a disease of small ruminants caused by Corynebacterium pseudotuberculosis. The pathogenesis of CLA is a slow process, and produces a chronic rather than an acute disease state. Acute phase proteins (APP) such as haptoglobin (Hp) serum amyloid A (SAA) and α1 acid glycoprotein (AGP) are produced by the liver and released into the circulation in response to pro-inflammatory cytokines. The concentration of Hp in serum increases in experimental CLA but it is not known if SAA and AGP respond in parallel or have differing response profiles. Results The concentration in serum of Hp, SAA and AGP in 6 sheep challenged with 2 × 105 cells of C. pseudotuberculosis showed significant increases (P C. pseudotuberculosis became detectable at 11 days p.i. and continued to rise throughout the experiment. Conclusion The serum concentrations of Hp, SAA and AGP were raised in sheep in an experimental model of CLA. An extended response was found for AGP which occurred at a point when the infection was likely to have been transforming from an acute to a chronic phase. The results suggest that AGP could have a role as a marker for chronic conditions in sheep.