Erythroid cells producing adult-type β-hemoglobin generated from human embryonic stem cells

1. A method of culturing human embryonic stem cells into erythroid cells producing adult-type β-hemoglobin, the method comprising the steps of:

(a) culturing human embryonic stem cells under conditions which favour differentiation of the cells into hematopoietic progenitors;

(b) isolating human embryonic stem cell-derived cells selected from the group consisting of CD31+, CD34+, and CD31+/CD34+ cells, wherein the cells are enriched in CD31+/CD43+, CD31+/CD34+, CD34+/CD43+ or CD31+/CD34+/CD43+ hematopoietic progenitors;

(c) culturing the hematopoietic progenitors to cause differentiation from CD34+/CD43+ hematopoietic progenitors to erythroid precursors followed by self-renewal/expansion of the erythroid precursors and maturation of the erythroid precursors; and

(d) recovering a population of matured erythroid cells, wherein essentially all of the live cells produce adult β-hemoglobin and fetal γ-hemoglobin but not embryonic ζ-hemoglobin.

2. The method of claim 1 , wherein the cells of step (d) are essentially free of lymphocytes.

3. The method of claim 1 , wherein the cells of step (d) contain less than 0.1% leukocytes.

4. The method of claim 1 , wherein the culturing of step (c) is in the presence of stem cell factor and erythropoietin under conditions preventing cell adherence.

5. The method of claim 1 , wherein the human embryonic stem cells are co-cultured with stromal cells to produce the hematopoietic progenitors.

6. The method of claim 1 , wherein at least 0.2×10 5 erythroid cells are generated from one human embryonic stem cell.

7. The method of claim 1 , wherein up to 2.0×10 5 erythroid cells are generated from one human embryonic stem cell.

8. The method of claim 1 , wherein the cells of step (d), which produce adult-type β-hemoglobin, are CD31−, CD34−, CD71+, CD235a+.

9. The method of claim 1 , wherein the purity of the isolated hematopoietic progenitors is greater than 95% at a single column run and cell viability, as evaluated by Trypan blue exclusion, is higher than 95%.

10. The method of claim 1 , wherein the CD31+/CD34+ cells comprise 30% to 50% CD31+/CD34+/CD43+ hematopoietic progenitors and 50% to 70% CD31+/CD34+/CD43−/KDR bright endothelial cells.

11. The method of claim 1 , wherein the cells express adult β-hemoglobin by 10 days (±10%) of culture, and wherein most of the cells have a phenotype and a morphology of erythroid cells.

12. The method of claim 1 , wherein after approximately 30 days (±10%) of culture, essentially all of the live cells (>95%) show positive stains with antibodies against fetal γ-hemoglobin and adult β-hemoglobin, but no positive staining with antibodies against embryonic ζ-hemoglobin.

13. The method of claim 1 , wherein after approximately 50 days (±10%) of culture, the cells of step (d) are CD31−/CD34− and show adult β-hemoglobin expression and no embryonic ζ-hemoglobin expression.

14. The method of claim 1 , wherein step (c) is performed in serum-free culture conditions.