POSITIVE AND POSITIVE/NEGATIVE CELL SELECTION MEDIATED BY PEPTIDE RELEASE

摘要

The invention provides a non-enzymatic method for the release of cells whichhave beem positively selected from a heterogeneouscell suspension by antibody-mediated binding to beads or other solid support.The method entails forming within the cell suspension acomplex comprising the solid support linked to a primary monoclonal antibody,which in tum is bound to a cell surface antigen on thetarget cells. The complex is separated from the cell suspension, and thencontacted with a specific peptide which binds to the primaryantibody, displacing the antibody from the cell surface antigen, therebyreleasing the target cell from the complex. The invention alsoprovides methods for positive/negative cell selection wherein target cellshaving a first antigen are selected from a heterogeneous cellsuspension containing undesired cells having a second antigen. The inventionalso provides methods for identifying a specific peptide usefulfor the release of a target cell from the binding of a specific monoclonalantibody. The methods of the invention are particularly useful forthe positive selection of CD34+ hematopoietic stem cells and the concomitantpurging of undesired tumor cells or lymphocytes from thepositively selected cell population. The purified CD34+ cell composition isthen useful for reinfusion to a cancer patient after high-dosetherapy in order to reconstitute the patient's immune system.