Purification of human blood basophils by negative selection using immunomagnetic beads.

A simple and rapid method for isolating highly purified and functionally intact basophils from normal human blood is described. Blood from healthy volunteers was centrifuged through a two layer Percoll density gradient. The majority of the basophils were recovered between Percoll layers with densities of 1.070 and 1.080, constituting 45.6% of total leukocytes. Lymphocytes, monocytes and neutrophils were extracted from this fraction using a panel of mabs in a direct or indirect selection procedure using immunomagnetic beads (Dynabeads) coated with sheep anti-mouse IgG. These negative immunoselection procedures produced a high yield of basophils with a mean purity of 97.8% (range 93.0-99.5%) and 97.0% (range 96.2-99.0%) using the direct and indirect method, respectively. The cells isolated by this method are viable, release histamine to various stimuli in a normal manner, and appear morphologically normal in transmission electron microscopy.