Evolution and development of membrane components in erythroid precursor cells in newly-developed two phase culture system.

A selective two phase liquid culture system for human erythroid progenitors was established, utilizing mononuclear cells obtained from human peripheral blood. The culture was performed in the presence of PHA-leukocyte conditioned medium for 7 days as the first phase, and nonphagocytic cells were recultured under hypoxic culture conditions containing iron-saturated transferrin and erythropoietin. During the second phase of the culture, differentiation to orthochromatic erythroblasts was observed on day 4, and to denucleated cells on day 8 with 16.8 +/- 0.7 micrograms/10(6) cells of hemoglobin level, respectively. Flow cytometric analyses revealed that, on day 3, cells became type M-positive, and the expression of ABH increased gradually corresponding to the extent of erythroid maturation. Lewis antigens and P antigens were expressed at day 5. The system is beneficial for studies on human membrane disorders, because the erythroid progenitors in human peripheral blood were utilized and the reasonable number of erythroid cells (0.5-1.5 x 10(7] was obtained with good erythroid maturation, such as denucleated erythrocytes.