Redistribution of RANTES/CCL5 released directionally by cytotoxic T lymphocytes on tumor cells
Objective To characterize the secretion of RANTES (reduced upon activation, normal T cell expressed and secreted) by cytotoxic T lymphocytes (CTL) which were activated by tumor target ceils. Methods CTL specific for tyrosinase peptide presented by HLA-A2 were co-incubated with HLA-A2-tyrosinase expressing melanoma target cells. The events of RANTES secretion by CIL and accumulation on the surface of the target ceils were observed by confocal microscopy. The kinetics of release of RANTES from intracellular stores was character- ized by intracellular FACS, and the transfer of RANTES protein from the CTL to the surface of the target cells was measured by surface FACS. The co-localization of RANTES and perforin was detected by three-color immunofluo- rescence confocal microscopy. Results RANTES released from intracellular stores was observed at 20 rain and was found maximal at 6 h. RANTES was detected on the target cells at 20 min after co-incubation of CTL with tu- mor cells. RANTES and pefforin co-contributed to forming the immune synapse. Conclusion CTL activated by tumor cell targets elicits a vectorial release of RANTES resulting in the redistribution of RANTES on target cells.