Generation of Multipotent Early Lymphoid Progenitors from Human Embryonic Stem Cells

Abstract

During human embryonic stem cell (ESC) hematopoietic differentiation, the description of the initial steps of lymphopoiesis remains elusive. Using a two-step culture procedure, we identified two original populations of ESC-derived hematopoietic progenitor cells (HPCs) with CD34⁺CD45RA⁺CD7⁻ and CD34⁺CD45RA⁺CD7⁺ phenotypes. Bulk cultures and limiting dilution assays, culture with MS5 cells in the presence of Notch ligand Delta-like-1 (DL-1), and ex vivo colonization tests using fetal thymic organ cultures showed that although CD34⁺CD45RA⁺CD7⁻ HPCs could generate cells of the three lymphoid lineages, their potential was skewed toward the B cell lineages. In contrast, CD34⁺CD45RA⁺CD7⁺ HPCs predominantly exhibited a T/natural killer (NK) cell differentiation potential. Furthermore these cells could differentiate equivalently into cells of the granulo-macrophagic lineage and dendritic cells and lacked erythroid potential. Expression profiling of 18 markers by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) revealed that CD34⁺CD45RA⁺CD7⁻ and CD34⁺CD45RA⁺CD7 ⁺ HPCs express genes of the lymphoid specification and that CD34⁺CD45RA⁺CD7⁻ cells express B-cell-associated genes, while CD34⁺CD45RA⁺CD7 ⁺ HPCs display a T-cell molecular profile. Altogether, these findings indicate that CD34⁺CD45RA⁺CD7⁻ and CD34⁺CD45RA⁺CD7 ⁺ HPCs correspond to candidate multipotent early lymphoid progenitors polarized toward either the B or T/NK lineage, respectively. This work should improve our understanding of the early steps of lymphopoiesis from pluripotent stem cells and pave the way for the production of lymphocytes for cell-based immunotherapy and lymphoid development studies.