THE INVENTION PROVIDES A METHOD FOR PRODUCING POLYPEPTIDE PROTEIN PRODUCTS AND NUCLEIC ACID PRODUCTS HAVING REDUCED LEVELS OF ANTIGENICITY IN AN ANIMAL BEING TREATED WITH A BIOLOGIC PRODUCT. SOMATIC CELLS ARE ISOLATED FROM AN ANIMAL, TRANSFORMED INTO PLURIPOTENT STEM CELLS, TRANSFECTED WITH A NUCLEIC ACID(S) OF INTEREST, AND RE-DIFFERENTIATED TOWARDS SOMATIC CELLS KNOWN TO BE HIGH LEVEL PRODUCERS OF THE DESIRED NUCLEIC ACID PRODUCT. THE INVENTION CAN BE USED TO DERIVE A GENERAL CELL LINE TO TREAT POPULATIONS, RACIAL SPECIFIC CELL LINES TO TREAT ETHNIC GROUPS, OR PATIENT SPECIFIC CELL LINES TO TREAT INDIVIDUALS. ADDITIONALLY, THE INVENTION PROVIDES A METHOD TO ALLOW INDUCED PLURIPOTENT STEM CELLS TO BE RE-DIFFERENTIATED TOWARDS THEIR SOMATIC CELL OF ORIGIN SO THAT THE CELLS CAN BE USED TO THERAPEUTICALLY TREAT AN ANIMAL WITHOUT RESULTING TERATOMA FORMATION. (FIG. 1)
