[HTML][HTML] IRF-5-Mediated Inflammation Limits CD8+ T Cell Expansion by Inducing HIF-1α and Impairing Dendritic Cell Functions during Leishmania Infection

A Hammami, T Charpentier, M Smans… - PLoS pathogens, 2015 - journals.plos.org
A Hammami, T Charpentier, M Smans, S Stäger
PLoS pathogens, 2015journals.plos.org
Inflammation is known to be necessary for promoting, sustaining, and tuning CD8+ T cell
responses. Following experimental Leishmania donovani infection, the inflammatory
response is mainly induced by the transcription factor IRF-5. IRF-5 is responsible for the
activation of several genes encoding key pro-inflammatory cytokines, such as IL-6 and TNF.
Here, we investigate the role of IRF-5-mediated inflammation in regulating antigen-specific
CD8+ T cell responses during L. donovani infection. Our data demonstrate that the …
Inflammation is known to be necessary for promoting, sustaining, and tuning CD8+ T cell responses. Following experimental Leishmania donovani infection, the inflammatory response is mainly induced by the transcription factor IRF-5. IRF-5 is responsible for the activation of several genes encoding key pro-inflammatory cytokines, such as IL-6 and TNF. Here, we investigate the role of IRF-5-mediated inflammation in regulating antigen-specific CD8+ T cell responses during L. donovani infection. Our data demonstrate that the inflammatory response induced by IRF-5 limits CD8+ T cell expansion and induces HIF-1α in dendritic cells. Ablation of HIF-1α in CD11c+ cells resulted into a higher frequency of short-lived effector cells (SLEC), enhanced CD8+ T cell expansion, and increased IL-12 expression by splenic DCs. Moreover, mice with a targeted depletion of HIF-1α in CD11c+ cells had a significantly lower splenic parasite burden, suggesting that induction of HIF-1α may represent an immune evasive mechanism adopted by Leishmania parasites to establish persistent infections.
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