Primate embryonic stem cells

Abstract

A purified preparation of primate embryonic stem cells is disclosed. This preparation is characterized by the following cell surface markers: SSEA-1 (−); SSEA-4 (+); TRA-1-60 (+); TRA-1-81 (+); and alkaline phosphatase (+). In a particularly advantageous embodiment, the cells of the preparation are human embryonic stem cells, have normal karyotypes, and continue to proliferate in an undifferentiated state after continuous culture for eleven months. The embryonic stem cell lines also retain the ability, throughout the culture, to form trophoblast and to differentiate into all tissues derived from all three embryonic germ layers (endoderm, mesoderm and ectoderm). A method for isolating a primate embryonic stem cell line is also disclosed.

1 .- 26 . (canceled) 
     
     
         27 . A method of differentiating primate embryonic stem cells into derivatives of endoderm, the method comprising:
 (a) obtaining a culture of primate embryonic stem cells, wherein the primate embryonic stem cells have the potential to differentiate into derivatives of endoderm;   (b) culturing the primate embryonic stem cells so that they differentiate into derivatives of endoderm.