C-di-AMP up-regulates T cell co-stimulatory molecules preferentially on conventional murine dendritic cells (DCs).

<p>(<b>A</b>) <i>In vivo</i> effects of c-di-AMP on mouse APCs. Flow cytometric analysis of DCs (CD11c⁺) and MΦs (CD11c⁻, CD11b⁺) from the nose-associated lymphoid tissue (NALT), the cervical lymph nodes (CLN) or the mediastinal lymph nodes (MLN) 24 h after i. n. administration of c-di-AMP in mice. (<b>B</b>) <i>In vitro</i> effects of c-di-AMP on mouse DCs. Murine bone marrow derived model conventional (cDCs) and plasmacytoid DCs (pDCs) were generated by culturing in the presence of Flt3l and incubated for 24 h with 5 µg/ml c-di-AMP or without additives (control). Cells were decorated with fluorescently labeled antibodies against identification markers CD11c (DCs), CD11b (cDCs), B220 (pDCs), and MHC class II, CD80 and CD86. The diagrams show the normalized median fluorescence intensity (fold increase as compared to the control) analyzed by flow cytometry. Error bars are SEM for n = 3. Differences are statistically significant at <i>p</i><0.01 (**) or <i>p</i><0.05 (*).