Phenotypic analysis and colony-forming activity of cryopreserved hematopoietic cells in human fetal liver

Cryopreserved human fetal liver cells have a wide clinical application. The objective of the work was to determine the immunophenotype and the colony-forming activity of the cryopreserved hematopoietic human fetal liver cells (HFL). The fresh-thawed initial HFL cell suspension contains high numbers of glycophorin-A-positive cells, erythroid progenitor cells of different degree of commitment. The content of CD45+ cells is 2.3 ± 0.3%, while the content of hematopoietic stem cells candidates, CD34+ AC133+ is 0.9 ± 0.1% and 0.4 ± 0.1%, respectively. The density centrifugation resulted in 2.5-4.5-fold increase in the content of CD34+ and AC133+ cells. When cultured in semisolid methylcellulose medium supplemented with growth factors (GM-CSF, IL-3, SCF, erythropoietin) the cryopreserved HFL cell suspension gave rise to 506.6 ± 70.8 (for 105 cells explanted) myeloid colonies of three types: CFU-GEMM, BFU-E, and CFU-GM. The age-specific differences were detected in the number of colonies: the preparations of 6-9 weeks of gestation give rise to 3-fold bigger number of CFU-GEMM than the preparations of 10-12 weeks do. Thus, the cryopreserved human fetal liver cells contain hematopoietic stem cells that are capable for the multilineage differentiation in vitro.