Method of sorting cells

Abstract

A method of sorting cells, particularly, but not exclusively, sperm cells, is described. The method comprises the use of a surface decontamination medium to strip the cells of any extra-cellular surface contamination and to then subject to stripped cells to a charge based on separation.

1 . A method of sorting cells, the method comprising the steps of treating the cells to remove extra-cellular surface contamination and subjecting the treated cells to a charge-based separation process.  
     
     
         2 . A method according to  claim 1 , in which endogenous cell membrane properties are maintained during the removal of surface contamination.  
     
     
         3 . A method according to  claim 1  or  claim 2 , in which surface contamination is removed from the cells using a medium containing egg yolk or derivatives thereof.  
     
     
         4 . A method according to  claim 3 , in which the egg yolk or derivative thereof is present in the surface contamination removal medium at a concentration of up to 30% volume/volume.  
     
     
         5 . A method according to any  claim 3  or  claim 4 , in which the egg yolk or derivative thereof comprises chicken egg yolk.  
     
     
         6 . A method according to any preceding claim, in which the charge based separation process is an electrophoretic process.  
     
     
         7 . A method according to  claim 6 , in which the electrophoretic process is conducted in a mobile liquid separation medium.  
     
     
         8 . A method according to  claim 6  or  claim 7 , in which the electrophoretic conditions of the electrophoretic process are constant throughout the separation chamber.  
     
     
         9 . A method according to  claim 7  or  claim 8 , in which the electrophoretic process comprises free-flow electrophoresis.  
     
     
         10 . A method according to any preceding claim, in which the sorted cells are selected from the extreme poles of the separation range.  
     
     
         11 . A method according to  claim 10 , in which the sorted cells are selected from both extreme poles of the separation range.  
     
     
         12 . A method according to any preceding claim in which the cells are sperm cells.  
     
     
         13 . A method according to  claim 12 , in which the surface contamination removed comprises accessory proteins, secretions added to the sperm cells during the process of cell membrane assembly, secretions added to the sperm cells during the process of cell maturation, secretions added to the sperm cells during the process of cell transport, secretions added to the sperm cells during the process of cell storage within the male reproductive tract, micro-organisms from the male reproductive tract and other contaminants or micro-organisms introduced during ejaculation.  
     
     
         14 . A method according to  claim 12  or  claim 13 , in which the cells are mammalian sperm cells.  
     
     
         15 . A method according to any one of  claims 12  to  14 , in which the sorted cells are sperm cells bearing X-chromosomes.  
     
     
         16 . Sperm cells bearing X-chromosomes sorted using a method according to any preceding claim.  
     
     
         17 . A method of producing non-human female embryos, the method comprising the steps of treating sperm cells to remove extra-cellular surface contamination, subjecting the treated sperm cells to a charge-based separation process to separate the X- and Y-chromosome bearing sperm cells, and using X-chromosome bearing sperm cells separated thereby to fertilise an egg.  
     
     
         18 . A non-human female embryo produced using the method of  claim 17.