Heterogeneity in the mobilization of cytoplasmic calcium by human polymorphonuclear leukocytes in response to fMLP, C5a and IL-8/NAP-1

The visible excitation and emission wave-lenghts of the recently developed fluorescent Ca2+ indicator fluo-3 permit analysis of the intracellular Ca2+ concentration, (Ca2+)i, in flow cytometry with a 488-nm argon laser. The role of (Ca2+)i in human polymorphonuclear leukocyte heterogeneity was investigated in response to formyl-methionyl-leucyl-phenylalanine (fMLP), C5a, and interleukin 8/neutropil attractant/activation protein 1 (IL-8/NAP-1) by flow cytometry. The (Ca2+)i changes in different subpopulations within a heterogeneous cell suspension were resolved upon stimulation with fMLP. Using an anti-CD16 phycoerythrin-conjugated antibody and fluo-3 simultaneously, neutrophils affected and nonaffected in Ca2+ mobilization were distinguished in two patients suffering from glycogen storage disease type 1b. In normal neutrophils, a different time course of Ca2+ mobilization of neutrophil subpopulations immdiately after stimulation with fMLP was detected.