@article{SchwarzRemerNahrendorfetal.2013, author = {Schwarz, Tobias and Remer, Katharina A. and Nahrendorf, Wiebke and Masic, Anita and Siewe, Lisa and M{\"u}ller, Werner and Roers, Axel and Moll, Heidrun}, title = {T Cell-Derived IL-10 Determines Leishmaniasis Disease Outcome and Is Suppressed by a Dendritic Cell Based Vaccine}, series = {PLoS Pathogens}, volume = {9}, journal = {PLoS Pathogens}, number = {6}, doi = {10.1371/journal.ppat.1003476}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130385}, pages = {e1003476}, year = {2013}, abstract = {Abstract In the murine model of Leishmania major infection, resistance or susceptibility to the parasite has been associated with the development of a Th1 or Th2 type of immune response. Recently, however, the immunosuppressive effects of IL-10 have been ascribed a crucial role in the development of the different clinical correlates of Leishmania infection in humans. Since T cells and professional APC are important cellular sources of IL-10, we compared leishmaniasis disease progression in T cell-specific, macrophage/neutrophil-specific and complete IL-10-deficient C57BL/6 as well as T cell-specific and complete IL-10-deficient BALB/c mice. As early as two weeks after infection of these mice with L. major, T cell-specific and complete IL-10-deficient animals showed significantly increased lesion development accompanied by a markedly elevated secretion of IFN-γ or IFN-γ and IL-4 in the lymph nodes draining the lesions of the C57BL/6 or BALB/c mutants, respectively. In contrast, macrophage/neutrophil-specific IL-10-deficient C57BL/6 mice did not show any altered phenotype. During the further course of disease, the T cell-specific as well as the complete IL-10-deficient BALB/c mice were able to control the infection. Furthermore, a dendritic cell-based vaccination against leishmaniasis efficiently suppresses the early secretion of IL-10, thus contributing to the control of parasite spread. Taken together, IL-10 secretion by T cells has an influence on immune activation early after infection and is sufficient to render BALB/c mice susceptible to an uncontrolled Leishmania major infection. Author Summary The clinical symptoms caused by infections with Leishmania parasites range from self-healing cutaneous to uncontrolled visceral disease and depend not only on the parasite species but also on the type of the host's immune response. It is estimated that 350 million people worldwide are at risk, with a global incidence of 1-1.5 million cases of cutaneous and 500,000 cases of visceral leishmaniasis. Murine leishmaniasis is the best-characterized model to elucidate the mechanisms underlying resistance or susceptibility to Leishmania major parasites in vivo. Using T cell-specific and macrophage-specific mutant mice, we demonstrate that abrogating the secretion of the immunosuppressive cytokine IL-10 by T cells is sufficient to render otherwise susceptible mice resistant to an infection with the pathogen. The healing phenotype is accompanied by an elevated specific inflammatory immune response very early after infection. We further show that dendritic cell-based vaccination against leishmaniasis suppresses the early secretion of IL-10 following challenge infection. Thus, our study unravels a molecular mechanism critical for host immune defense, aiding in the development of an effective vaccine against leishmaniasis.}, language = {en} } @article{SolbachBogdanMolletal.1989, author = {Solbach, W. and Bogdan, C. and Moll, Heidrun and Lohoff, M. and R{\"o}llinghoff, M.}, title = {Parasit{\"a}re Evasionsmechanismen: Beispiel Leishmanien}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30920}, year = {1989}, abstract = {Leishmanien besitzen eine Vielzahl von Mechanismen, die humorale und zellul{\"a}re Immunabwehr effektiv zu unterlaufen. Diese h{\"a}ngen eng mit der Expression von haupts{\"a}chlich zwei Glykokonjugaten auf der Parasitenoberfl{\"a}che zusammen, dem gp63 und dem Lipophosphoglykan. Die Parasiten sind einerseits schlechte Aktivatoren des alternativen Komplementweges und umgehen damit ihre eigene extrazellul{\"a}re Lyse. Oberfl{\"a}chengebundene Komplementfaktoren f{\"o}rdern andererseits die Aufnahme der Leishmanien durch Makrophagen. Solange diese nicht durch T-Zellen aktiviert sind, dienen sie den Parasiten als "Refugium". Dies gilt insbesondere, als Leishmanien in der Lage sind, 1. den "oxidative burst" zu hemmen; 2. toxische Sauerstoffmetaboliten zu entgiften; 3. abbauende lysosomale Enzyme zu hemmen und 4. das saure Milieu in den Lysosomen f{\"u}r ihren eigenen Metabolismus auszunutzen. Schließlich unterlaufen Leishmanien die zellul{\"a}re Immunabwehr des Wirts, indem sie die Aktivierung von T-Lymphozyten hemmen und die Expansion von T-Zell-Sub-populationen bewirken, die f{\"u}r ihr eigenes {\"U}berleben n{\"u}tzlich sind.}, language = {de} }