In vitro growth of sheep erythroid progenitors

We have attempted to define culture conditions suitable to support the in vitro growth of early erythroid progenitors (BFU-E), derived from the liver or bone marrow and blood of fetal and adult sheep. Testing a wide variety of conditions showed that only some batches of fetal lamb sera made a notable difference to growth. BFU-E from normal fetal blood were demonstrated sporadically: they appeared regularly in low numbers in blood taken during erythroid (anaemic) stress. Adult blood only contained sporadic BFU-E during severe anaemic stress. This difficulty in demonstrating circulating BFU-E in sheep may be due to a genuine paucity of such cells or to an undefined requirement for in vitro growth.