The invention relates to the use of cells from cell lines, which are derived from early embryonic stages, for the donor-specific increase in transplantation tolerance and for repairing damaged tissue. Areas of application of the invention include the field of medicine and the pharmaceutical industry. The aim of the invention is to produce a donor-specific immunotolerance in order to prevent a rejection of the transplanted tissue due to an immune response and thus to be able to limit the administration of immunosuppressives. In order to produce a donor-specific immunotolerance, embryonic stem cell-like cell lines (ECL) are obtained from blastocysts and are transfected with genetic material of the donor, which codes for the MHC haplotypes.; The cells produced in such a manner are administered to the recipient before the transplantation for producing an immunotolerance against the tissue to be transplanted or for regenerating already damaged tissue.