A diverse fibroblastic stromal cell landscape in the spleen directs tissue homeostasis and immunity.

We show that diverse cell types express the cell surface marker PDPN in the spleen, including three TRC subsets, glial cells, mesothelial cells, and ARCs, despite that PDPN has been widely used as a marker of TRC in the spleen. The spleen is a complex organ that performs multiple functions during homeostasis and during immune responses. We defined strategies to isolate and analyze stromal cell subsets from mice and human spleens and performed RNA-seq, scRNA-seq, flow cytometry, and confocal microscopy to interrogate splenic stromal cells and to compare these with stromal cells from LNs. Both PD-1 SP + sp (programmed cell death-1) TCF1 SP - sp (T cell factor 1) TIM3 SP + sp (T-cell immunoglobulin domain and mucin domain 3) exhausted T (T SB EX sb ) cells and PD-1 SP + sp TCF1 SP + sp precursor exhausted T (T SB PEX sb ) cells were reduced in SpiB SP CCL19 sp mice responding to LCMV CL13 infection. [Extracted from the article]