Fig. 2.

Deletion of CD33 does not impair engraftment, hematopoietic repopulation, and function in NSGS mice. (A) Schematic of experimental design. (B and C) BM-derived CD34⁺ cells engraftment and repopulation: (B) Peripheral blood (7 wk) and (C) whole BM (21 wk) posttransplant analyzed for cells of various lineages, as indicated. CD34⁺CD33^Del cells show the same engraftment (CD45⁺) as control cells as well as comparable percentage of mature myeloid and lymphoid cells. BM CD34⁺CD33^Del cells show comparable percentage of myeloid (progenitor CD123⁺, mature CD14⁺), and lymphoid (progenitor CD10⁺, mature CD19⁺) T cells (CD3⁺) and stem cells CD34⁺38⁻. (D and E) CB-derived CD34⁺ cell engraftment and repopulation: (D) Peripheral blood (9 wk) and (E) BM (21 wk) posttransplant analyzed for cells of various lineages, as indicated. CD34⁺CD33^Del cells show same engraftment (CD45⁺) as control cells, as well as comparable percentage of mature myeloid and lymphoid cells. BM CD34⁺CD33^Del cells show comparable percentage of myeloid (progenitor CD123⁺, mature CD14⁺) and lymphoid (progenitor CD10⁺, mature CD19⁺), T cells (CD3⁺), and stem cells CD34⁺38⁻. Data were analyzed using unpaired t test and no significant differences were found in all of the groups examined (P > 0.05). All data are represented as mean ± SEM (two independent experiments, two donors). (F–I) In vitro and in vivo functional assays. (F) CD34⁺CD33^Del show comparable development of myeloid lineage than CD34⁺CD33^WT in NSGS mice. Frequencies of neutrophils, monocytes, cDC, pDC, mast cells, and basophils in the BM aspirates of NSGS mice injected with CB CD34⁺CD33^WT or CD34⁺CD33^Del cells. (Control n = 12, CD34⁺CD33^Del n = 13). (G) In vitro E. coli bioparticles phagocytosis assay of in vitro CD33^WT or CD33^Del differentiated monocytes. CD33^Del monocytes show similar phagocytosis capacity (two independent experiments, two donors). (H) Response to LPS-induced Toll-like receptor activation is similar in NSGS mice injected with CD34⁺CD33^WT or CD34⁺CD33^Del cells. Analysis of plasma cytokines level at 0 and 4h30 after intraperitoneal injection of 15 μg LPS (Control n = 12, CD34⁺CD33^Del n = 13). (I) Peritoneal cavity analysis 2 h after intravenous injection of E. coli bioparticles (Control n = 3 CD34⁺CD33^Del n = 5), untreated mice (♦). Mouse and syringe images designed by Freepik and Kiranshastry from Flaticon.