A-C, Induction of ICAM1 and IL8 by lymphocytederived membranebound and soluble LIGHT in human endothelial cells. Human endothelial cells were co-incubated in supernatant containing soluble LIGHT, isolated soluble LIGHT and stimulated (PMA 100 ng/ml + ionomycin 1 μg/ml) and unstimulated whole lymphocytes for 3 hours. Thereafter, HUVECS were harvested and analyzed for expression of the adhesion molecule ICAM-1 and IL-8 by real-time PCR. After stimulation ICAM-1 and IL-8 were significantly increased in all experiments (Figure 5A - 5C). To confirm that the stimulation of the endothelial cells was due to LIGHT, specific anti-LIGHT-antibodies were used. After pre-incubation of whole lymphocytes and LIGHT containing medium with anti-LIGHT antibody, cytokine induction was partially abolished. After pre-treatment of isolated LIGHT containing medium with anti LIGHT, the effects were even completely abolished (Figure 5B). These data correspond to one representative experiment of three performed. *P < 0.05 and **P < 0.005 vs stimulated cells without blocking antibody.