Disclosure of a mammalian cytoplasmic donor cell line. Disclosure of a patient specific cell line. Methods to obtain a mammalian cytoplasmic donor cell line by fusing a differentiated mammalian cell and a functionally enucleated mammalian embryonic cell line. Methods to obtain a mammalian cytoplasmic donor cell line by fusing a differentiated mammalian cell and a functionally enucleated human cancer cell. Methods to obtain a patient specific cell line of a cell type similar to a mammalian cytoplasmic donor cell line by functionally enucleating the mammalian cytoplasmic donor cell line and fusing the functionally enucleated mammalian cytoplasmic donor cell line with a differentiated cell obtained from the patient. A method of treatment of a human patient by administering the patient-specific cell line to the patient.