Figure 1. All trans retinoic acid depletes primitive lymphoid progenitors in bone marrow and increases B cells in the spleen.

RAG-1/GFP mice were treated with ATRA or placebo pellets for seven days. Bone marrow, splenocytes and thymocytes were isolated, dead cells were excluded by trypan blue staining, flow cytometry was performed and absolute numbers of cells in the spleen (A or C), one femur (B or C) or thymus (C) were calculated. cDC were defined as B220⁻CD11b⁺CD11c⁺; NK cells were defined as NK1.1⁺; ELP (early lymphoid progenitor) were defined as Lin⁻ RAG-1⁺ Scal-1⁺c-Kit^Hi; Pro-L were defined as Lin⁻RAG-1⁺Sca-1⁺c-Kit^Lo; LSK was defined as Lin⁻GFP⁻Sca1⁺c-Kit^Hi; CMP (common lymphoid progenitor) were defined as Lin⁻GFP⁻Sca1⁻c-Kit^Hi. All data are reported as mean ± S.D for n= 4. *, p < 0.05, and **, p < 0.01 (Student's t-test). All numbers are given as millions of cells, and P values were bolded when p < 0.05 in Fig. 1C. The results shown are representative of five independent experiments.