Depletion of macrophages markedly reduces LPS- or LTA-induced lymphangiogenesis in the DLNs. CDL (25 mg/kg, CD) was given intravenously to deplete macrophages at 1 day before and after the intradermal injection of LPS (LPS + CDL) or LTA (LTA + CDL). As a control, CL (25 mg/kg) was given in the same manner (LPS + CL, LTA + CL). As alternative controls, PBS (P), CL, or CDL-only was given in the same manner. At day 3 after the injection of LPS or LTA, the DLNs were sampled and sectioned for histologic analysis or digested for flow cytometry. (A) Tissue sections were coimmunostained for LYVE-1, CD31, or CD11b and merged. ↓ indicates lymphatic sprouts. Scale bars represent 50 μm. Quantification of lymphatic (LV) and blood vessel (BV) densities (%; B), number of lymphatic sprouts (C), and number of CD11b⁺/Gr-1⁺ cells in the gated region (No/GA; E) are shown. All bars represent mean ± SD from 4 to 5 mice. *P < .05 versus CL; #P < .05 versus LPS + CL or LTA + CL. (D) Flow cytometric analysis of CD11b⁺/Gr-1⁺ macrophages in the DLNs.