Immunomagnetic purification of T cell subpopulations

There are two types of magnetic cell isolation technologies, one column-based and the other tube-based. The column-based technology utilizes nano-sized particles that need to pass through a ferromagnetic spheres column to increase cell-capture capacity. The tube-based system utilizes micron-sized beads that can be selected using a magnet applied to the tube. The beads are used for direct or indirect labeling of cells. Direct labeling is achieved with antibodies coupled to magnetic particles directly added to the cell suspension. For indirect labeling the cells are first labeled with the antibody of interest; the antibody can be simple, biotinylated, or fluorochrome-conjugated. Subsequently, beads coated with streptavidin or anti-immunoglobulin, anti-biotin, anti-fluorochrome antibodies are used to specifically mark the subpopulation of interest. Separation of target cells can be achieved using positive or negative selection or a combination of the two. Quality of the sample preparation is critical to obtain good purification and yield.