Mycobacterium vaccae induces a population of pulmonary CD11c+ cells with regulatory potential in allergic mice.
The hygiene hypothesis proposes that common, harmless microorganisms, present throughout our evolutionary history, have helped to develop immunoregulatory mechanisms that prevent inappropriate immune responses by the host. Using a mouse model of allergic pulmonary inflammation, we report that treatment with an ubiquitous saprophytic mycobacterium, Mycobacterium vaccae, significantly reduces allergic inflammation by decreasing type 2 responses such as eosinophilia and IL-4 expression. Rather than observing an increase in type-1 cytokine expression, we found elevated production of IL-10 in the lungs suggesting a role for regulatory T cells. Since induction of these cells may be dependent on APC, we investigated the effects of M. vaccae treatment on pulmonary CD11c+ cells. Increased levels of IL-10, TGF-beta and IFN-alpha mRNA were detected in CD11c+ cells from M. vaccae-treated allergic mice. We propose that M. vaccae-induced CD11c+ cells have a potential regulatory role at the site of inflammation through their secretion of immunomodulatory cytokines.
University College London, Department of Medical Microbiology, Windeyer Institute of Medical Sciences, London, GB.
Victoria C
VC
Adams
SR Pharma, London, GB.
Jon R F
JRF
Hunt
SR Pharma, London, GB.
Roberta
R
Martinelli
SR Pharma, London, GB.
Rebecca
R
Palmer
University College London, Department of Medical Microbiology, Windeyer Institute of Medical Sciences, London, GB.
Graham A W
GAW
Rook
SR Pharma, London, GB.
Laura Rosa
LR
Brunet
D000818:Animals; D000938:Antigen-Presenting Cells / Q000737:chemistry / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D039521:CD11c Antigen / Q000032:analysis*; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D007249:Inflammation / Q000276:immunology / Q000628:therapy; D007376:Interleukin-2 / Q000096:biosynthesis; D008168:Lung / Q000166:cytology / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009161:Mycobacterium; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000628:therapy; D018418:Th2 Cells / Q000276:immunology
D039521:CD11c Antigen; D016207:Cytokines; D007376:Interleukin-2