Effects of LTD4 on immature CD34⁺/CD38^low/− hematopoietic progenitor cells.

(A) Isolated PB CD34⁺ progenitor cells were loaded with the calcium indicator Fluo-3 and stained with a CD38-PE antibody. Ten seconds after addition of LTD4, a shift of the green Fluo-3 fluorescence was observed due to intracellular calcium mobilization (right panel), which occurred in both CD38⁺ and more primitive CD38^low/− progenitor cells. (B) Analysis of isolated PB CD34⁺ cells by flow cytometry before and after chemotaxis showed a similar percentage of more immature CD34⁺/CD38^low/− cells (bold rectangular gate) in the starting population (ii, before migration, 5.25%), in spontaneously migrating cells (iii, 6.15%), and in migrated cells attracted by LTD4 (iv, 6.35%). In this particular experiment, a more than 2-fold increase of the migration rate in response to LTD4 (50 nM) was observed. The isotype-specific control is shown in panel i.