In vitro processing and presentation of a lipidated cytotoxic T-cell epitope derived from measles virus fusion protein

Lipopeptidic formulations have been described as efficient activators of cy totoxic T lymphocytes (CTL). To better understand the pathway via which lip opeptides reach the MHC class I molecules we studied the intracellular proc essing and presentation of a measles virus-derived CTL epitope, to which a palmitoyl moiety was added synthetically. The palmitoyl group was conjugate d to the N-terminus either directly or via a spacer sequence. The use of si ngle or double fluorescent-labeled lipopeptides allowed the visualization o f intracellular processing of these antigens using confocal microscopy. Our data indicate that the spacer composition influences internalization of th e conjugate into the cell, proteasomal degradation, translocation into the ER by the transporter associated with antigen processing (TAP), and the int racellular trafficking of lipopeptides. (C) 2001 Elsevier Science Ltd. All rights reserved.