Organ-specific and stage-dependent control of Leishmania major infection by inducible nitric oxide synthase and phagocyte NADPH oxidase.
In the Leishmania major mouse model of cutaneous leishmaniasis inducible nitric oxide synthase (iNOS) is crucial for the killing of the parasite in the skin and draining lymph node. However, the effector mechanism operating against L. major in the spleen is unknown. As reactive oxygen intermediates might play a role, we analyzed macrophages and mice lacking the gp91phox subunit of the phagocyte NADPH oxidase (phox) for their ability to combat an infection with L. major. Macrophages from wild-type and gp91phox(-/-) mice had an equal capacity to kill L. major after activation by cytokines. Unlike iNOS, the activity of phox was dispensable for the resolution of the acute skin lesions and exerted only a limited effect on the containment of the parasites in the draining lymph node, but was essential for the clearance of L. major in the spleen. During the chronic phase of infection, parasites persisted at high levels in gp91phox(-/-) mice, and cutaneous lesions re-emerged in approximately 60% of these mice. gp91phox deficiency did not impair the expression of iNOS or the production of TNF and IFN-gamma. These results demonstrate that iNOS and phox are both required for the control of L. major in vivo and display unexpected organ- and stage-specific anti-leishmanial effects.
Institute of Clinical Microbiology, Immunology and Hygiene, University of Erlangen-Nuremberg, Erlangen, Germany.
Martin
M
Blos
Ulrike
U
Schleicher
F Janaina
FJ
Soares Rocha
Udo
U
Meissner
Martin
M
Röllinghoff
Christian
C
Bogdan
D000818:Animals; D007371:Interferon-gamma / Q000096:biosynthesis; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D009928:Organ Specificity; D010586:Phagocytes / Q000201:enzymology / Q000276:immunology*
D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D019255:NADPH Oxidases