A fluorescent reporter model for the visualization and characterization of T_DC

T(DC )are hematopoietic cells that combine dendritic cell (DC) and conventional T-cell markers and functional properties. They were identified in secondary lymphoid organs (SLOs) of naive mice as cells expressing CD11c, major histocompatibility molecules (MHC)-II, and the T-cell receptor (TCR). Despite thorough characterization, a physiological role for T(DC )remains to be determined. Unfortunately, using CD11c as a marker for T(DC )has the caveat of its upregulation on different cells, including T cells, upon activation. Here, we took advantage of Zbtb46-GFP reporter mice to explore the frequency and localization of T(DC )in different tissues at steady state and upon viral infection. RNA sequencing analysis confirmed that T(DC )sorted from Zbtb46-GFP mice have a gene signature that is distinct from conventional T cells and DC. In addition, this reporter model allowed for identification of T(DC )in situ not only in SLOs but also in the liver and lung of naive mice. Interestingly, we found that T-DC numbers in the SLOs increased upon viral infection, suggesting that T-DC might play a role during viral infections. In conclusion, we propose a visualization strategy that might shed light on the physiological role of T-DC in several pathological contexts, including infection and cancer.