Expression of NRAMP1 and iNOS in Mycobacterium avium subsp. paratuberculosis naturally infected cattle

Abstract

Paratuberculosis (PTB) is a chronic disease caused by M. avium subsp. paratuberculosis (MAP) that affects several animal species, and some studies have suggested that there may be a relationship between Crohn's disease and PTB. Significant aspects of PTB pathogenesis are not yet completely understood, such as the role of macrophages. Natural resistance-associated macrophage protein 1 (NRAMP1) and the inducible nitric oxide synthase (iNOS) molecules have shown nonspecific effects against several intracellular pathogens residing within macrophages. However, these molecules have been scarcely studied during natural infection with MAP. In this work, changes in NRAMP1 and iNOS expression were surveyed by immunohistochemistry in tissue samples from MAP-infected cattle and healthy controls. Our findings show strong specific immunolabeling against both NRAMP1 and iNOS molecules, throughout granulomatous PTB-compatible lesions in ileum and ileocaecal lymph nodes from paratuberculous cattle compared with uninfected controls, suggesting a relationship between the expression of these molecules and the pathogenesis of PTB disease.