Differentiated cells suitable for human therapy

Abstract

This invention provides a system for producing differentiated cells from a stem cell population for use wherever a relatively homogenous cell population is desirable. The cells contain an effector gene under control of a transcriptional control element (such as the TERT promoter) that causes the gene to be expressed in relatively undifferentiated cells in the population. Expression of the effector gene results in depletion of undifferentiated cells, or expression of a marker that can be used to remove them later. Suitable effector sequences encode a toxin, a protein that induces apoptosis, a cell-surface antigen, or an enzyme (such as thymidine kinase) that converts a prodrug into a substance that is lethal to the cell. The differentiated cell populations produced according to this disclosure are suitable for use in tissue regeneration, and non-therapeutic applications such as drug screening.

What is claimed as the invention is:  
     
         1 . A pair of isolated cell populations, consisting of: 
 a first cell population comprising undifferentiated cells from a line of human embryonic stem (hES) cells; and    a second cell population that is free of undifferentiated hES cells, but which contains progeny of said hES cell line.    
     
     
         2 . The cell populations of  claim 1 , wherein the cells contain a nucleic acid molecule comprising the structure P-X, wherein: 
 X is a nucleic acid sequence encoding a product that is lethal to a cell in which it is expressed, or renders a cell in which it is expressed susceptible to a lethal effect of an external agent; and    P is a transcriptional control element that causes X to be preferentially expressed in undifferentiated cells.    
     
     
         3 . The cell populations of  claim 2 , wherein X encodes a toxin, or a protein that induces or mediates apoptosis.  
     
     
         4 . The cell populations of  claim 2 , wherein X encodes an enzyme that converts a prodrug to a compound that is lethal to a cell in which X is expressed.  
     
     
         5 . The cell populations of  claim 4 , wherein X encodes a thymidine kinase.  
     
     
         6 . The cell populations of  claim 2 , wherein P-X is an introduced heterologous molecule.  
     
     
         7 . The cell populations of  claim 2 , wherein P is an endogenous transcriptional control element.  
     
     
         8 . The cell populations of  claim 2 , wherein P is an OCT-4 promoter or a promoter of telomerase reverse transcriptase (TERT).  
     
     
         9 . The cell populations of  claim 1 , wherein the second cell population is a population of neurons or neural precursor cells.  
     
     
         10 . The cell populations of  claim 1 , wherein the second cell population is a population of hepatocytes.  
     
     
         11 . The cell populations of  claim 1 , wherein the second cell population is a population of cardiomyocytes.  
     
     
         12 . The cell populations of  claim 1 , wherein the second cell population is formulated for tissue reconstitution or regeneration in a human patient.