TY  - JOUR
A1  - Schleicher, Ulrike
A1  - Paduch, Katrin
A1  - Debus, Andrea
A1  - Obermeyer, Stephanie
A1  - König, Till
A1  - Kling, Jessica C.
A1  - Ribechini, Eliana
A1  - Dudziak, Diana
A1  - Mougiakakos, Dimitrios
A1  - Murray, Peter J.
A1  - Ostuni, Renato
A1  - Körner, Heinrich
A1  - Bogdan, Christian
T1  - TNF-Mediated Restriction of Arginase 1 Expression in Myeloid Cells Triggers Type 2 NO Synthase Activity at the Site of Infection
JF  - Cell Reports
N2  - Neutralization or deletion of tumor necrosis factor (TNF) causes loss of control of intracellular pathogens in mice and humans, but the underlying mechanisms are incompletely understood. Here, we found that TNF antagonized alternative activation of macrophages and dendritic cells by IL-4. TNF inhibited IL-4-induced arginase 1 (Arg1) expression by decreasing histone acetylation, without affecting STAT6 phosphorylation and nuclear translocation. In Leishmania major-infected C57BL/6 wild-type mice, type 2 nitric oxide (NO) synthase (NOS2) was detected in inflammatory dendritic cells or macrophages, some of which co-expressed Arg1. In TNF-deficient mice, Arg1 was hyperexpressed, causing an impaired production of NO in situ. A similar phenotype was seen in L. major-infected BALB/c mice. Arg1 deletion in hematopoietic cells protected these mice from an otherwise lethal disease, although their disease-mediating T cell response (Th2, Treg) was maintained. Thus, deletion or TNF-mediated restriction of Arg1 unleashes the production of NO by NOS2, which is critical for pathogen control.
KW  - TNF
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164897
VL  - 15
IS  - 5
ER  - 
TY  - JOUR
A1  - Ribechini, Eliana
A1  - Eckert, Ina
A1  - Beilhack, Andreas
A1  - Du Plessis, Nelita
A1  - Walzl, Gerhard
A1  - Schleicher, Ulrike
A1  - Ritter, Uwe
A1  - Lutz, Manfred B.
T1  - Heat-killed Mycobacterium tuberculosis prime-boost vaccination induces myeloid-derived suppressor cells with spleen dendritic cell–killing capability
JF  - JCI Insight
N2  - Tuberculosis patients and mice infected with live Mycobacterium tuberculosis accumulate high numbers of myeloid-derived suppressor cells (MDSCs). Here, we hypothesized that dead M. tuberculosis vaccines also may induce MDSCs that could impair the efficacy of vaccination. We found that repeated injections of M. tuberculosis vaccines (heat-killed M. tuberculosis in incomplete Freund’s adjuvant, such as Montanide) but not single or control vaccines without M. tuberculosis strongly expanded CD11b\(^+\) myeloid cells in the spleen, leading to T cell suppression of proliferation and killing ex vivo. Dead M. tuberculosis vaccination induced the generation of CD11b\(^+\)Ly6C\(^{hi}\)CD115\(^+\) iNOS/Nos2\(^+\) monocytic MDSCs (M-MDSCs) upon application of inflammatory or microbial activation signals. In vivo these M-MDSCs were positioned strategically in the splenic bridging channels and then positioned in the white pulp areas. Notably, within 6–24 hours, in a Nos2-dependent fashion, they produced NO to rapidly kill conventional and plasmacytoid DCs while, surprisingly, sparing T cells in vivo. Thus, we demonstrate that M. tuberculosis vaccine induced M-MDSCs do not directly suppress effector T cells in vivo but, instead, indirectly by killing DCs. Collectively, we demonstrate that M. tuberculosis booster vaccines induce M-MDSCs in the spleen that can be activated to kill DCs. Our data suggest that formation of MDSCs by M. tuberculosis vaccines should be investigated also in clinical trials.
KW  - Immunology
KW  - Infectious disease
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201973
VL  - 13
IS  - 4
ER  -