title: A strategy for efficient cross-presentation of CTL-epitope peptides leading to enhanced induction of in vivo tumor immunity.
abstract: The activation of antitumor cytotoxic T-lymphocytes (CTLs) depends on how efficiently the relevant tumor antigen peptides are delivered into the major histocompatibility complex (MHC) class I presentation pathway in antigen presenting cells (APCs). An elegant approach to promote the peptide-MHC class I association has been described for enhanced peptide transportation into the endoplasmic reticulum (ER) by adding an ER insertion signal sequence (Eriss). Nevertheless, this approach does not appear potent enough to induce in vivo tumor protective immunity. Herein, we present a novel peptide-vaccine strategy based on the combined utilization of Eriss and fusogenic liposomes (FLs) capable of directly introducing encapsulated CTL-epitope peptides into the MHC class I pathway of APCs. APCs pulsed with free peptides, FL-encapsulated peptides, or FL-encapsulated Eriss-conjugated peptides exhibited comparable levels of antigen-presenting activity at early phases after pulsing. Interestingly, whereas in the first two methods the APC ability began to decline 40 to 60 h after pulsing, FL-encapsulated Eriss(+) peptides allowed APCs to retain peptide-presentation activity for at least 140 h. This advantage of FL-encapsulated Eriss(+) peptides correlated with the induction of more potent antitumor immunity compared with soluble Eriss(+) or Eriss(-) peptides or FL-encapsulated Eriss(-) peptides when they were administered in vivo. Thus, Eriss-conjugated CTL-epitope peptides encapsulated in FLs provide a highly efficient tumor-vaccine to enhance the induction of in vivo tumor immunity.
authors.affiliation: Department of Biotechnology and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hayashi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Wakita
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tsutsumi
authors.forename: Tadanori
authors.initials: T
authors.lastname: Mayumi
authors.forename: Yohei
authors.initials: Y
authors.lastname: Mukai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Naoki
authors.initials: N
authors.lastname: Okada
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004339:Drug Compounding; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005805:Genes, MHC Class I; D008081:Liposomes; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000276:immunology*; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism*
chemical_list: D000939:Epitopes; D008081:Liposomes; D010455:Peptides