title: PLGA nanoparticle-mediated delivery of tumor antigenic peptides elicits effective immune responses.
abstract: The peptide vaccine clinical trials encountered limited success because of difficulties associated with stability and delivery, resulting in inefficient antigen presentation and low response rates in patients with cancer. The purpose of this study was to develop a novel delivery approach for tumor antigenic peptides in order to elicit enhanced immune responses using poly(DL-lactide-co-glycolide) nanoparticles (PLGA-NPs) encapsulating tumor antigenic peptides. PLGA-NPs were made using the double emulsion-solvent evaporation method. Artificial antigen-presenting cells were generated by human dendritic cells (DCs) loaded with PLGA-NPs encapsulating tumor antigenic peptide(s). The efficiency of the antigen presentation was measured by interferon-γ ELISpot assay (Vector Laboratories, Burlingame, CA). Antigen-specific cytotoxic T lymphocytes (CTLs) were generated and evaluated by CytoTox 96(®) Non-Radioactive Cytotoxicity Assay (Promega, Fitchburg, WI). The efficiency of the peptide delivery was compared between the methods of emulsification in incomplete Freund's adjuvant and encapsulation in PLGA-NPs. Our results showed that most of the PLGA-NPs were from 150 nm to 500 nm in diameter, and were negatively charged at pH 7.4 with a mean zeta potential of -15.53 ± 0.71 mV; the PLGA-NPs could be colocalized in human DCs in 30 minutes of incubation. Human DCs loaded with PLGA-NPs encapsulating peptide induced significantly stronger CTL cytotoxicity than those pulsed with free peptide, while human DCs loaded with PLGA-NPs encapsulating a three-peptide cocktail induced a significantly greater CTL response than those encapsulating a two-peptide cocktail. Most importantly, the peptide dose encapsulated in PLGA-NPs was 63 times less than that emulsified in incomplete Freund's adjuvant, but it induced a more powerful CTL response in vivo. These results demonstrate that the delivery of peptides encapsulated in PLGA-NPs is a promising approach to induce effective antitumor CTL responses in vivo.
authors.affiliation: Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA. wma@ucsd.edu
authors.forename: Wenxue
authors.initials: W
authors.lastname: Ma
authors.forename: Mingshui
authors.initials: M
authors.lastname: Chen
authors.forename: Sharmeela
authors.initials: S
authors.lastname: Kaushal
authors.forename: Michele
authors.initials: M
authors.lastname: McElroy
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Cengiz
authors.initials: C
authors.lastname: Ozkan
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
authors.forename: Carol
authors.initials: C
authors.lastname: Kruse
authors.forename: Douglas
authors.initials: D
authors.lastname: Grotjahn
authors.forename: Thomas
authors.initials: T
authors.lastname: Ichim
authors.forename: Boris
authors.initials: B
authors.lastname: Minev
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000008:administration & dosage*; D019496:Cancer Vaccines / Q000008:administration & dosage*; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology; D016503:Drug Delivery Systems; D006801:Humans; D007274:Injections, Intraperitoneal; D019344:Lactic Acid / Q000737:chemistry*; D058965:MART-1 Antigen / Q000008:administration & dosage; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D050997:Nanomedicine; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology; D009374:Neoplasms, Experimental / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011471:Prostatic Neoplasms / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D058965:MART-1 Antigen; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid