Purification of human basophils. Their response to anti-IgE

Although usually the least prevalent blood leukocyte, the basophil can release potent soluble factors in response to multiple triggers. We purified basophils from normal volunteers by means of isopycnic centrifugation and affinity binding of mononuclear cells. The majority of the basophils from most subjects were recovered in a band formed between Percoll layers with densities of 1.070 and 1.080; at this stage basophils represented a mean of 22% of total leukocytes. These cells were reacted with monoclonal antibodies to T (OKT-11) and B (anti-HLA-DR) lymphocytes; B and T cells were removed by adsorption to insoluble antibodies against mouse immunoglobulin resulting in a mean purity of 75% basophils with a yield of 54%. These highly enriched basophils resembled unpurified basophils in terms of (1) intracellular histamine content, (2) spontaneous release of histamine in buffer, and (3) percentage of histamine released by anti-IgE. These findings suggest that the techniques used to purify the basophils do not affect the functional integrity of human basophils.