Abstract: An apparatus for separating a selected cell population from blood or a blood component includes a container, a plurality of particles having a reactant that binds to a selected cell population and a separating device for separating the selected cell population from the blood or blood component. The particles have a density that allows gravity settling of the particles through the blood or blood component. The separating device can include a device for compressing the container, a magnet or a filter, for example. The apparatus can also include a mixing device for mixing the particles with the blood or blood component. The reactant bound to the particles can include an antibody or antibody fragment, such as lectin or a lectin fragment.