1e, f). Cd83-promoter activity was exceptionally high in monocytes upon transition to an APC-phenotype (CD11c+/MHC-II+), which implies that CD83 expression is not exclusively induced in activated microglia during neuroinflammation. However, the eGFP signal in microglia further increases during the recovery phase, especially in the spinal cord, despite declining CD11c expression (Fig. 2f). This indicates a more diverse role of CD83 expression during neuroinflammation than simply marking activation. To advance this idea, we reassessed data from a model of relapsing-remitting EAE (RR-EAE), which more closely resembles the clinical progression of MS29. Thereby, we disclose that Cd83 expression was elevated during the whole disease course, particularly in remission and recovery phases (Fig. 2g). Furthermore, this approach proved that Cd83 mRNA is actively translated in microglia during neuroinflammation30. Collectively, these data suggest that CD83 expression not only marks early-activated microglial cells but is also important during the resolution of neuro-inflammatory conditions.
