Abstract: The enrichment of a population of keratinocyte stem cells (KSCs) from a preparation of keratinocytes and KSCs, includes pre-enrichment by contacting a sample of keratinocytes and KSCs with a collagen-coated culture plate for a sufficient time for KSCs to adhere, followed by washing away the non-adherent cells and recovering the adherent cells. The recovered adherent cells are sorted by their expression level of EGFR so that cells are recovered that have an expression level of EGFR of less than about 50% of the maximum level of EGFR expression, and the recovered cells have an expansion potential of at least 109 after about 100 days in culture.

Abstract: The invention concerns a method for enriching a population of keratinocyte stem cells, from a preparation of keratinocytes, comprising a pre-enrichment step in keratinocyte stem cells by adherence of said preparation on a constituent of extra-cellular matrices, in particular recognized by molecules involved in the adherence of the keratinocytes, in particular by the integrin family receptors, particularly collagen, for a period of time between about 5 and about 30 minutes, preferably between about 10 and about 20 minutes, advantageously 12 minutes, and in recuperating the stem cells which have adhered on said constituent of extra-cellular matrices by separation in conditions enabling to maintain the viabilty of the stem cells which have adhered, in particular by trypsinization, particularly using trypsin 0.05% and EDTA 0.02% to obtain a population of adherent cells.

Abstract: A method is disclosed for gene transfer into a culture of primitive stem cells which comprises a prestimulation step of adding a blocking agent to block at least one inhibitor of a cell cycle of said primitive stem cells. The prestimulation is time-limited for a period of less than approximately 36 hours so that said culture of primitive stem cells retains hematopoietic potential.

Abstract: A method is disclosed for gene transfer into a culture of primitive stem cells which comprises a prestimulation step of adding a blocking agent to block at least one inhibitor of a cell cycle of said primitive stem cells. The prestimulation is time-limited for a period of less than approximately 36 hours so that said culture of primitive stem cells retains hematopoietic potential.