The purification of human basophils

Studies utilizing human basophils have provided considerable insight into the mechanism and clinical significance of IgE-mediated phenomena (1-8). Basophils represent the only human IgE-binding, mediator-releasing cell that can be obtained from patients as a single-cell suspension. Their usefulness has been limited, however, by the fact that they represent but 0.5 to 1.0% of the total white blood cell population. Although guinea pig basophils have been purified (9), an earlier method for human basophil purification by Day et al. (10) has not been confirmed in this, and several other laboratories (personal communications from T. Ishizaka and R. Orange), Further attempts (11) to purify the human basophil have been only partially successful (10 to 40% purity), provided a low yield, and were long and laborious procedures, which raised questions about the cells' viability. We here present a method that is moderately fast (4 hr) and results in high purity, high recovery, and cells that are fully capable of releasing histamine in response to anti-IgE antibody. The method of isolation takes advantage of the presence, on the basophils, of unoccupied IgE-Fc receptors. Cells are passively sensitized with penicillin- (BPO)³ specific IgE antibody, passed over a small column of Sepharose coupled to penicillin, and eluted with monovalent hapten, BPO-FLYS.