Functional expression of LTB₄ receptors on murine BM-DCs. Immature (iDCs) and mature DCs (20 ng/mL TNF-α for 24 hours) were generated from BM CD34⁺ precursors in vitro. Chemotaxis (left panel): Ligand-dependent chemotaxis of both iDCs and mDCs was measured using a 48-well micro chemotaxis chamber, as described in “Chemotaxis assay.” Data are the mean ± SE of cells from 3 individual fields for each concentration from a representative experiment of at least 3 repetitions. Calcium mobilization (right panel): Both iDCs and mDCs loaded with Indo-1 were induced with various concentrations of LTB₄, and Ca²⁺ mobilization was measured. The y-axis indicates the fluorescence ratio (F340/380). Arrows indicate LTB₄ addition.