CFU-E stands for Colony Forming Unit-Erythroid. It arises from

CFU-GEMM CFU-GEMM is a colony forming unit that generates myeloid cells. CFU-GEMM cells are the oligopotential progenitor cells for myeloid cells; they are thus also called common myeloid progenitor cells or myeloid stem cells. "GEMM" stands for granulocyte ...

(via BFU-E, which stands for "erythroid burst-forming units") and gives rise to

proerythroblast A proerythroblast (or rubriblast, or pronormoblast) is the earliest of four stages in development of the normoblast. In histology, it is very difficult to distinguish it from the other "-blast" cells (lymphoblast, myeloblast, monoblast, and mega ...

Murine CFU-E assay

CFU-E is a stage of erythroid development between the BFU-E stage and the pro-erythroblast stage. CFU-E colony assay is designed to detect how many colony-forming-units of erythroid lineage there are in a hematopoietic tissue (bone marrow, spleen, or fetal liver), which may be reflective of the organism’s demand for oxygen delivery to the tissues or a hematopoietic disorder. Early erythroid progenitors are found at a quite low frequency relative to later stages of erythroid differentiation, such as the pro-erythroblast and the basophilic erythroblast stages which can be detected by flowcytometry directly ex-vivo. Furthermore, unlike for the pro-erythroblast and later stages of erythroid development, no truly reliable and unique positive flow-cytometric markers exist, though it is possible to use negative exclusion markers to deplete a cell population of other precursors and differentiated cells by cell sorting, thus greatly enriching it for the CFU-E activity. CFU-E cells express Epo receptor, c-Kit (Stem cell factor receptor),

transferrin receptor Transferrin receptor (TfR) is a carrier protein for transferrin. It is needed for the import of iron into the cell and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex thro ...

(CD71+), and are Ter119(glycophorin-A associated antigen)-negative. For the above reasons, the CFU-E assay, as inefficient and variable as it can often be, is still in use today. Cells at the CFU-E stage express some

erythropoietin receptor The erythropoietin receptor (EpoR) is a protein that in humans is encoded by the ''EPOR'' gene. EpoR is a 52kDa peptide with a single carbohydrate chain resulting in an approximately 56-57 kDa protein found on the surface of EPO responding cells. ...

(EpoR), and thus can be induced to terminally differentiate in vitro in 2–3 days in the presence of only

erythropoietin Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bo ...

(Epo) (together with the basic contents of culture media: FBS, BSA in IMDM). Methylcellulose is a semisolid media additive that allows an investigator to stain (with diaminobenzidine reagent for hemoglobin) and then count individual colonies, each arising from a single plated progenitor that is at the CFU-E stage. By day 2 from the time of plating, each CFU-E colony will contain between 8 (minimum) and 64 hemoglobinized cells most of which are in their end-stage of erythroid differentiation. It is possible to see a small spectrum of hemoglobinization level and possibly cell size, indicating that some cells in the colony have achieved the end-stage faster than others. Cell number in a colony is important because pro-erythroblast stage is also Epo-responsive (expresses Epo receptor), but the proliferative capacity of these cells is not as high, thus yielding a colony with fewer than 8 cells. Likewise, an earlier stage of erythroid differentiation may also yield colonies in Epo-only medium, but these colonies would likely be smaller and/or not hemoglobinized, since the stages before the CFU-E stage (MEP and BFU-E) require other factors (IL-3 etc) and more time for growth that will also delay the terminal differentiation and hemoglobinization.

References

External links

* {{Blood physiology Blood cells Colony forming units