Generation of pluripotent cells from fibroblasts

1. A method comprising:

contacting a human somatic cell with at least one retroviral vector comprising polynucleotides encoding at least four de-differentiation factors selected from the group consisting of a (i) KLF4, (ii) OCT4, (iii) SOX2, (iv) c-MYC or n-MYC, and (v) NANOG,

culturing the somatic cell to express the at least four de-differentiation factors;

selecting cells that express a Tumor Rejection Antigen 1-61 and/or 1-81,

subculturing the selected cells to obtain an enriched population of de-differentiated/induced stem cells.

2. The method of claim 1 , wherein the retroviral vector further comprises a marker gene.

3. The method of claim 2 , further comprising selecting cells showing a decrease or loss of expression of the marker and subculturing the selected cells to obtain an enriched population of de-differentiated/induced stem cells.

4. The method of claim 3 , wherein the marker gene encodes a fluorescent protein.

5. The method of claim 2 , wherein the marker gene is operably linked to at least one de-differentiation factor coding sequence so that the at least one de-differentiation factor is co-expressed with the marker.

6. The method of claim 5 , wherein the at least one de-differentiation factor coding sequence comprises a c-MYC or n-MYC coding sequence.

7. A method of generating a human stem cell comprising contacting a somatic cell with a retroviral vector comprising a set of polynucleotides encoding at least four de-differentiation factors selected from the group consisting of a KLF4, OCT4, SOX2, c-MYC or n-MYC, NANOG or any combination thereof, under conditions wherein the cell is infected with the retroviral vector; culturing the infected cell under conditions for expression of the polynucleotides encoding the at least four de-differentiation factors; and isolating cells expressing a TRA-1-81 and/or TRA-1-61 and a reduced or loss of expression of a vector gene to obtain human stem cells.

8. The method of claim 7 , wherein the culturing is on a growth arrested feeder layer.

9. A method of claim 7 , wherein the somatic cell is a fibroblast cell.