Characterization of embryonic stem-like cell lines derived from embryoid bodies.

Embryoid bodies (EB) were formed by TT2 embryonic stem (ES) cells in vitro. ES-like cell lines (ESLC) were established by culturing cells obtained by disaggregation of EB at 4, 8 and 20 days after culture, and designated ESLC4, ESLC8 and ESLC20, respectively. Flow cytometric analysis indicated that the cell surface expression of Le(a) on ESLC was less than that of original TT2 ES cells, but the expression of L-CAM was comparable. After suspension culture, all of the ESLC cells formed cystic EB in vitro. In addition, some ESLC4- and ESLC8-derived EB showed signs of beating. Although coat color chimeras were able to be produced with ESCL4 at a lower rate than parental ES cells, the cells did not contribute to germ line cells in chimeras. These results suggest that the ESLC had less pluripotent than parental ES cells and also that EB formation is not useful in obtaining pluripotent cells.