Novel splenic antigen-presenting cells derive from a Lin(-) c-kit(lo) progenitor.

The main DC subsets in murine spleen arise from BM-derived precursors. Recently, a novel APC type was described in spleen. To determine if spleen contains the progenitors of this subset, a stromal coculture system was used to assess candidate progenitors for their hematopoietic potential. Here, the progenitor of that subset is identified as a spleen endogenous Lin(-)c-kit(lo) hematopoietic progenitor and is most highly enriched among the Lin(-)c-kit(lo)CD34(+) subset. Dendritic-like cells produced in vitro functionally resemble the previously described in vivo equivalent subset with high endocytic capacity and capability for antigen-specific activation of CD8(+) T cells but not CD4(+) T cells.