Molecular mechanisms involved in lymphocyte transendothelial migration induced by L-selectin stimulation and SDF-1. HUVECs were cultured in Transwells. Chromium-labeled lymphocytes were added to the upper chamber and SDF-1 was added to the lower chamber. As indicated, lymphocytes were pretreated with fucoidan, L-selectin cross-linking, antiadhesion molecules, or chemical inhibitors. (A) L-selectin cross-linking increased lymphocyte migration to SDF-1. (B) Fucoidan-stimulated lymphocyte migration to SDF-1 was inhibited by anti-LFA-1, PTX, and herbimycin A. (C) L-selectin cross-linking did not affect migration induced by RANTES. ▨. indicates no fucoidan; ▤, with fucoidan. *P < .05 compared with SDF-1 alone; **P ≤ .05 compared with SDF-1 + fucoidan.