A comparison of ovine monocyte-derived macrophage function following infection with Mycobacterium avium ssp. avium and Mycobacterium avium ssp. paratuberculosis.
Mycobacterium avium ssp. paratuberculosis causes Johne's disease in ruminants, whereas the antigenically and genetically similar subspecies Mycobacterium avium ssp. avium is less virulent. In this study, we compared one strain of each subspecies for its ability to survive, induce cytokines, suppress MHC class I and II expression and induce apoptosis or necrosis in ovine monocyte-derived macrophages. Both subspecies survived intracellularly and induced the secretion of IL-10. Low levels of TNF-alpha were detected after infection with both subspecies at 4 h. IL-12 was not upregulated after infection. Downregulation of MHC class I and II was evident in response to infection with both M. avium ssp. avium and M. avium ssp. paratuberculosis. No significant cytotoxicity was detectable in ovine macrophages after the addition of bacteria. M. avium ssp. paratuberculosis induced slightly more apoptosis than M. avium ssp. avium. Still the overall rate of apoptosis was very low and both subspecies suppressed LPS-induced macrophage apoptosis.
Berger
Sven T
ST
Disease Research Laboratory, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
Griffin
Frank T
FT
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology / Q000378:metabolism; D018664:Interleukin-12 / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D009162:Mycobacterium avium / Q000276:immunology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology*; D009336:Necrosis / Q000276:immunology; D010283:Paratuberculosis / Q000276:immunology / Q000382:microbiology; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12