(A) Phase microscopy of AGM-S3 cells established. (B) Appearance of cobblestone-like colonies generated in the coculture of human CB CD34⁺ cells with AGM-S3 cells at day 14 of culture. (C) Appearance of a part of a mixed hematopoietic colony produced by the cells harvested from the coculture of CD34⁺CD38⁻ cells with AGM-S3 cells at week 6 of culture.