In vitro activities of CXCL12 in pDCs and their progenitors. (A-C) Effects of CXCL12 on the generation of pDCs (A,B) or cDCs (C) from primitive hematopoietic cells in wild-type mice (A,C) and pIpC-treated MxCre/CXCR4^f/null mice 3 weeks after the final pIpC treatment (A), and from more mature pDC progenitors in wild-type mice (B). Cells sorted in LSK Flt3^lo cells (A,C) and Flt3⁺ subsets of CLP and CMP fractions (B) were cultured in medium containing SCF and IL-7 (−Flt3L) or SCF, IL-7, and Flt3L (+Flt3L) in the absence or presence of CXCL12. The numbers of CD11c^intB220⁺PDCA-1⁺ pDCs (A,B) and CD11c^hiB220⁻CD11b⁺ cDCs (C) measured at 4 days (B) or 14 days (A,C) by flow cytometry are shown (n = 3-6). (D) Chemotactic activity of pDC progenitors toward CXCL12. Transwell migration assay of LSK Flt3^lo cells, cells in Flt3⁺ subsets of CLP and CMP fractions, and CD11c^intB220⁺PDCA-1⁺ pDCs without CXCL12 or with CXCL12 (n = 3). Error bars represent SD of the mean.