Article

Lymphoid Priming in Human Bone Marrow Begins Prior to CD10 Expression with Up-Regulation of L-selectin

Department of Pathology & Laboratory Medicine, University of California, Los Angeles, California, USA.
Nature Immunology (Impact Factor: 24.97). 09/2012; 13(10):963-71. DOI: 10.1038/ni.2405
Source: PubMed

ABSTRACT Expression of the cell-surface antigen CD10 has long been used to define the lymphoid commitment of human cells. Here we report a unique lymphoid-primed population in human bone marrow that was generated from hematopoietic stem cells (HSCs) before onset of the expression of CD10 and commitment to the B cell lineage. We identified this subset by high expression of the homing molecule L-selectin (CD62L). CD10(-)CD62L(hi) progenitors had full lymphoid and monocytic potential but lacked erythroid potential. Gene-expression profiling placed the CD10(-)CD62L(hi) population at an intermediate stage of differentiation between HSCs and lineage-negative (Lin(-)) CD34(+)CD10(+) progenitors. CD62L was expressed on immature thymocytes, and its ligands were expressed at the cortico-medullary junction of the thymus, which suggested a possible role for this molecule in homing to the thymus. Our studies identify the earliest stage of lymphoid priming in human bone marrow.

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    • "These include CCR7 and its ligand (CCL19/21), CCR9 and its ligand (CCL25) [25], [26], and PSGL1 [27]. In humans, the mechanisms of thymus colonization have been less studied, but similar chemokines may be involved, at least during the fetal and perinatal periods [8], [10], [28]. In our study, whereas PSGL1 expression was not modified (Data not shown), CCR7 and CCR9 mRNA expression was reduced after allo-HSCT, even in the absence of aGVHD. "
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