ABSTRACT
I. BACKGROUND Enormous progress has been achieved in recent decades in cell-sorting tech niques. Fluorescence-activated cell sorting (FACS) for multiple parameters and more recently magnetic cell sorting (MACS) allow highly sophisticated and accurate sorting of even the rarest cells from very inhomogeneous cell mixtures. A decisive factor in this progress has been the variety and quality of antibodies (Abs) now available for many surface markers, that distinguish functional cell subsets.
