In order to minimize any murine embryonic fibroblast (MEF) contribution in our analysis, H9 cells were cultured on a low density of irradiated MEFs (ICR MEFs) resulting in a ratio of approximately >8:1 H9 cell to MEF.

Bright-field image of H9 cell culture.
The culture of H9 on low-density MEFs had no adverse affects on cell morphology, growth rate, or undifferentiated status as determined by immunohistochemistry for pluripotency markers (e.g. Oct4, SSEA-3, Tra-1-60). In addition, H9 cells grown on a minimal feeder layer maintain the ability to generate derivates of ectoderm, mesoderm, and endoderm upon differentiation.
Immunohistochemical Analysis of Pluripotency Markers
Teratoma Formation
Embryoid Bodies (EB)