ALTERED INTESTINAL MACROPHAGE PHENOTYPE IN-OVINE PARATUBERCULOSIS

The expression of macrophage surface markers that are likely to be imp ortant in antigen presentation and cell interactions was examined in n ormal sheep and those with clinical paratuberculosis. Immunohistologic al studies demonstrated that intestinal macrophages in diseased sheep expressed MHC class II, LFA-1 and CR4 antigens weakly compared with no rmal tissues. Reverse transcriptase-polymerase chain reaction analysis of MHC class II mRNA in intestinal whole tissue samples showed no sig nificant difference between control and diseased groups. A reduction i n molecules such as MHC class II and LFA-1 on the surface of infected macrophages could have implications for survival of the intracellular mycobacteria and the persistence of infection.