Leukotriene B4 is a complete secretagogue in human neutrophils: a kinetic analysis

The interactions have been studied of leukotriene B₄ (LTB₄) and 20-COOH-LTB₄ with human neutrophils (PMN). Kinetic studies, utilizing continuous recording techniques, showed that LTB₄ activates PMN with respect to aggregation, mobilization of membrane-associated Ca²⁺, $\underset{\dot{}}{?}$ generation, and degranulation within seconds of exposure. Dose-response studies indicate 1) that LTB₄ is much more potent than its dicar?ylic acid derivative (20-COOH-LTB₄) or its all trans-isomer, and 2) that PMN responses to these agents are largely dependent upon pretreatment of the cells with cytochalasin B. These properties were similar to those of the microbial ionophores, ionomycin and A23187. Results demonstrate that LTB₄ rapidly activates PMN and indicate that LTB₄ serves as a complete secretagogue. Moreover, they provide additional evidence that oxidized fatty acids activate human PMN.