Use of Monoclonal Antibodies with Magnetic Particles to Separate Cell Subpopulations by Positive Selection

The use of magnetic particles in combination with monoclonal antibodies (MAbs) has greatly simplified sorting heterogeneous populations of cells into specific subpopulations (1–35). MAbs which recognize particular cell surface markers provide the specificity necessary to distinguish one cellular population from another. Magnetic particles provide an effective, yet gentle, physical force to move the target population away from the remaining cells. Two forms of selection have been used by researchers: positive and negative selection. Positive selection is the isolation of the desired population from the cellular mixture and does not imply the complete removal of a target cell population. Negative selection is the elimination of an undesired population from the cellular mixture. The methods for negative selection were outlined in Chapter 25 . In this chapter, we focus on the methods used in positive selection (9,28). As with negative-selection techniques, there are a variety of methods in use. We outline one general method and discuss variations in methodology in Section 4. of this chapter.