Genetic Resistance to Johne's Disease in Cattle

Abstract

Paratuberculosis (Johne's disease) is an economically significant, infectious disease of ruminants caused by Mycobacterium avium subsp paratuberculosis, and characterized by progressive weight loss and nonresponsive diarrhea. Genetic factors have been associated with differences in host susceptibility to bovine paratuberculosis. Research has been aimed at detecting associations between susceptibility and polymorphisms at candidate genes with no definitive results. Several gene products are candidates for this association. Interferon gamma is an inducible cytokine with a crucial role in the innate host response to intracellular bacteria. Toll-like receptors are trans-membrane structures responsible for coordination of innate and adaptive immune responses. The SLC11A1 gene plays an important role in innate immunity, preventing bacterial growth in macrophages during the initial stages of infection. The objective of this candidate gene case-control study was to characterize the distribution of polymorphisms in three candidate genes related to the immune function; interferon gamma (BoIFNG), toll-like receptor 4 (TLR4), and solute carrier family 11 member1 (SLC11A1) genes, and test their association with paratuberculosis infection in cattle.