Fig. 5: CXCL12 enabled the maintenance of B lineage repopulating ability of HSCs in vitro.

a Experimental design. Sorted 50 cells in the HSC population from CD45.2⁺ wild-type mice were cultured for 28 days in the presence of SCF and TPO with or without CXCL12, and 75% of cells in each well were transplanted with 1×10⁶ CD45.1⁺ competitor bone marrow cells into CD45.1⁺CD45.2⁺ wild-type mice. b Donor chimerism of LSK-SLAM HSCs, GMPs, pro-B cells, and pre-B cells in the bone marrow of recipients at 16 weeks after transplantation is shown (n = 5). All error bars represent SE of the mean. c Representative flow cytometry plots of bone marrow and peripheral blood from recipient mice at 16 weeks after transplantation. d Donor-derived B lymphoid/myeloid (pro-B/GMP and pre-B/GMP) ratios in recipients at 16 weeks after transplantation are shown (n = 5). All error bars represent SE of the mean. Statistical significances were calculated using the two-tailed unpaired Student’s t test. Source data are provided as a Source data file. e Working model for how CXCL12 regulates HSCs to produce the required number of B cell progenitors. CAR cell-derived CXCL12 plays a critical role in the maintenance of HSCs, especially lymphoid-biased HSCs.