Multipotent hemopoietic progenitors (CFUMIX) in human fetal liver.

Colony formation by multipotent hemopoietic precursors (CFUMIX) from human fetal liver was studied in a methylcellulose culture system containing erythropoietin (Ep) and media conditioned by leukocytes in the presence of phytohemagglutinin (PHA-LCM). The 15 fetal livers used were obtained from 13-23-week-old abortuses. Morphologic characteristics of the fetal mixed colonies were similar to those of colonies derived from adult marrow cells. The number of colonies reached a maximum at about 15-17 days. Fetal liver CFUMIX was apparently more sensitive to added Ep than progenitors from adult bone marrow. Frequency of fetal liver precursors was higher than frequency of adult marrow precursors. Number of mixed colonies tended to increase with fetal age from 13 to 23 weeks of gestation (r = 0.547, P less than 0.05).