Abstract ▼ AI-Helper

Elevated levels of circulating intercellular adhesion molecule-1 (cICAM-1) have been reported in several human malignancies and cICAM-1 can be detected in the culture medium of many human tumor cell lines. It has been suggest that cICAM-1 may be involved in immune modulation and in immune escape of ...

Elevated levels of circulating intercellular adhesion molecule-1 (cICAM-1) have been reported in several human malignancies and cICAM-1 can be detected in the culture medium of many human tumor cell lines. It has been suggest that cICAM-1 may be involved in immune modulation and in immune escape of tumor cells by inhibition of leukocyte recruitment via competition with ICAM-1 on endothelial cells. However, the mechanisms involved in the generation of cICAM-1 are not clear yet. To investigate these mechanisms, we examined whether cICAM-1 is a membrane or a soluble type of ICAM-1. Western Blotting of tumor-conditioned medium showed that the molecular weight of cICAM-1 was similar to that of mICAM-1 not to that of sICAM-1. Most of cICAM-1 in conditioned medium was detected in tumor vesicle and the conditioned medium after removal of tumor vesicle had no detectable amount of ICAM-1. mICAM-1 associated with tumor vesicle shows more potent activity in the blocking of leukocyte adhesion to activated endothelial cells than sICAM-1 probably due to increasing the local concentration and dimerization of ICAM-1. Our data explain that the exact roles of cICAM-1 in immune modulation and escape of tumor cells from immune surveillance.

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