Fig. 4

CD117 expression enhances AML engraftment but is not essential to initiate leukemia. Pooled BM cells and splenocytes from primary engrafted NSG mice were magnetically sorted to CD34⁺CD117⁺ and CD34⁺CD117⁻ AML cells. a Methocult™ colony-forming unit (CFU) assay. Representative images at 3 weeks post-culture were shown. Colonies were counted microscopically and the mean number of colonies obtained in duplicate dishes (1 × 10⁴ cells inoculated per dish) was indicated. b, c Vary number of either CD34⁺CD117⁻ or CD34⁺CD117⁺ AML cells (1 × 10⁴, 5 × 10⁴ and 1 × 10⁵) were injected intrahepatically after sublethal irradiation in newborn NSG pups (n = 5 per group). Representative flow cytometry plots (b), frequency (c, above), and absolute count (c, below) of AML engraftment in peripheral blood at week 12 post-engraftment. Data are presented as mean frequency or absolute count of human CD45⁺ cells ± SEM. Two-tailed Mann Whitney U test; *p < 0.05, **p < 0.01. d Comparison of AML engraftment at endpoint (week 16 post-engraftment) in peripheral blood, spleen, and BM between newborn NSG pups engrafted with 1 × 10⁵ of CD34⁺CD117⁺ and CD34⁺CD117⁻ AML cells. Data are presented as mean frequency (d, above) or absolute count (d, below) of human CD45⁺ cells ± SEM. Two-tailed Mann Whitney U test; *p < 0.05. e, f Immunophenotypic analysis of CD34⁺CD117⁺ and CD34⁺CD117⁻ engrafted recipient mice. Frequency e and absolute count f of CD34 ⁻ CD117 ⁻, CD34 ⁻ CD117 ⁺, CD34 ⁺ CD117 ⁺, and CD34 ⁺ CD117 ⁻ subsets in peripheral blood, spleen, and BM at week 16 post-engraftment. Data are presented as mean frequency of human CD45⁺ cells or absolute count ± SEM. Two-tailed Mann Whitney U test; *p < 0.05, **p < 0.01