Apoptosis levels in bovine Johne's disease ileal lesions and association with bacterial numbers.

Abstract

Johne's disease (JD) is a chronic granulomatous enteritis caused bysubsp.(MAP). While it is generally accepted that MAP employs immune subversion mechanisms, aspects of the host-pathogen relationship are not fully understood. We sampled 3 ileal tissue sections from 17 naturally infected cattle (= 51 sections) to analyze differences in cell types, apoptosis, and phagocytic cells. Diffuse multibacillary (DM) was the most common lesion type (= 17) followed by diffuse intermediate (DI;= 15). DM lesions had significantly greater proportion of Treg cells (CD3FoxP3relative to all CD3T cells as compared to DI forms (< .05). CD68individual cell size was significantly smaller in DM than in diffuse lymphocytic (DL) forms (< .05). Area of caspase-3 positivity (apoptosis) was greater in DM lesions than DL (< .05) and DI (< .0001), and was linked to higher numbers of MAP within the macrophage.