The present invention concerns methods for de-differentiation and stabilize cells, such as progenitor cells, by introducing the cells into the cytoplasm of host oocytes, such as Xenopus laevis oocytes. Advantageously, this method obviates the need for any nuclear transfer procedure, which is known to disrupt the chromosomal architecture of donor and recipient cells. The present invention also concerns host oocytes encapsulating cells that have been introduced into their cytoplasm. The present invention also concerns cells that have been removed from the host oocytes.