Dendritic cells (DCs) recognize invading pathogens via specialized receptors, such as pattern recognition receptors. This leads to DC maturation of DCs including the upregulation of costimulatory molecules, secretion of cytokines and chemokines, and migration from the peripheral tissue into nearby lymph nodes, where they present the uptaken and processed antigens to T cells. In the spleen DCs have been described to present blood borne antigens to T cells. Overall, DCs can be separated into plasmacytoid DCs and conventional DCs type I (cDC1) and type II (cDC2), which can be migratory or resident. Splenic cDC2 have been recently described to be subdivided into ESAM⁺ and Clec12A⁺. The function and the localization regarding the two subsets of cDC2 are not clear at the current stage.
As the exact localization of the DCs is important for the capture of antigens but also the initiation of T cell immune responses, we are aiming to 1. Determine the localization of DC subsets in the secondary lymphoid organs under steady-state and inflammatory conditions, to 2. Determine the spatial distribution of DC subsets and T cells during antigen presenting, and to 3. Examine the establishment of memory T cell responses in dependence of the inflammatory stimuli and cross-correlation of early effects of spatial DC distribution with T cell memory formation of TEM, TCM, and TRM.
For this purpose, we established an easy confocal imaging protocol based on the newly described method, called Iterative Bleaching Extends multi-pleXity (IBEX). Till now, we have successfully set up 20 marker DC subset-specific staining protocols in the spleen. To outline our future plans, we intend to conduct experiments to explore the localization of the DC subsets in the presence of inflammatory stimuli in spleen and lymph nodes.  

Funding: DFG (DU548/6-1), German Research Foundation (DU548/2-1, RTG2599 (421758891)).