Effect of coculture with FL-derived Lyve-1⁺ feeder cells on LTR capacity of LSK/EPCR⁺ cells. (A) FL cells were sorted against CD45⁻Ter-119⁻Lyve-1⁺ fraction. (B) Significantly decreased chimerism of donor-derived LSK/EPCR⁺ cells in peripheral blood after 1-day culture without feeder cells (□) was recovered when cocultured with feeder layer of FL-derived Lyve-1⁺ cells () to the levels statistically equivalent to those of freshly transplanted LSK/EPCR⁺ cells. (C) Chimerism of donor-derived cells in BM 4 months after transplantation decreased significantly when cultured without feeder cells but not when cultured with FL Lyve-1⁺ feeder cells. (D) Population of LSK fraction 4 months after transplantation showed no statistical difference among the 3 conditions. (E) Chimerism of donor-derived LSK population was significantly decreased in cells cultured without feeder cells and sustained with coculture with FL Lyve-1⁺ feeder cells. (B-E) Freshly transplanted LSK/EPCR⁺ cells () and LSK/EPCR⁺ cells cocultured for 1 day with FL Lyve-1⁺ feeder cells () are shown. LSK/EPCR⁺ cells cultured without feeder cells (□) are also represented. Error bars represent SD (n = 4 or 5). *P < .05.