Differences in sensitivity to tumor-specific CTLs between primary and metastatic esophageal cancer cell lines derived from the same patient.

PURPOSE: MHC antigens and adhesion molecules, such as the intracellular adhesion molecule (ICAM-I), play an important role in cellular immune response. We examined the expression patterns of these molecules in both primary and metastatic esophageal carcinoma cells from the same patient and evaluated the cellular immune responses against these cells.
MATERIALS AND METHODS: In the esophageal cancer patient (H122), tumor cell lines were established from primary and subcutaneous metastatic lesions. We compared the expression of cell surface molecules on the metastatic tumor cell line (H122SC) with that on the primary tumor cell line (H122ESO) using flow cytometry. Moreover, we analyzed the differences in cellular immune responses against these cell lines, which expressed similar levels of the Tara antigen, using the Tara antigen-specific CTL clone.
RESULTS: H122SC ICAM-1 expression was significantly lower in H122ESO, and the Tara antigen-specific CTL clone produced lower levels of TNF in response to H122SC than H122ESO. ICAM-1 transfection into the H122SC rendered these cells as sensitive to the CTL clone as the H122ESO.
CONCLUSION: The metastatic tumor cells displayed lower regulated ICAM-1 expression levels and were less sensitive to specific CTLs. ICAM-1 downregulation may be one mechanism by which tumor cells escape immunologic surveillance.