title: Enhanced immunostimulatory effects of DNA-encapsulated peptide hydrogels.
abstract: DNA that encodes tumor-specific antigens represents potential immunostimulatory agents. However, rapid enzymatic degradation and fragmentation of DNA during administration can result in limited vector expression and, consequently, poor efficacy. These challenges have necessitated the use of novel strategies for DNA delivery. Herein, we study the ability of cationic self-assembling peptide hydrogels to encapsulate plasmid DNA, and enhance its immunostimulatory potential in vivo. The effect of network charge on the gel's ability to retain the DNA was assessed employing three gel-forming peptides that vary systematically in formal charge. The peptide HLT2, having a formal charge of +5 at neutral pH, was optimal in encapsulating microgram quantities of DNA with little effect on its rheological properties, allowing its effective syringe delivery in vivo. The plasmid, DNA(TA), encapsulated within these gels encodes for a melanoma-specific gp100 antigen fused to the alarmin protein adjuvant HMGN1. Implantation of DNA(TA)-loaded HLT2 gels into mice resulted in an acute inflammatory response with the presence of polymorphonuclear cells, which was followed by infiltrating macrophages. These cellular infiltrates aid in the processing of encapsulated DNA, promoting increased lymphoproliferation and producing an enhanced immune response mediated by CD4+/IFNγ+ expressing Th1 cells, and complemented by the formation of gp100-specific antibodies.
authors.affiliation: Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Medina
authors.affiliation: Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Li
authors.affiliation: Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: O M Zack
authors.initials: OM
authors.lastname: Howard
authors.affiliation: Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Micah
authors.initials: M
authors.lastname: Dunlap
authors.affiliation: Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Trivett
authors.affiliation: Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA. Electronic address: Joel.Schneider@nih.gov.
authors.forename: Joel P
authors.initials: JP
authors.lastname: Schneider
authors.affiliation: Laboratory of Molecular Immunoregulation, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA. Electronic address: oppenheJ@mail.nih.gov.
authors.forename: Joost J
authors.initials: JJ
authors.lastname: Oppenheim
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D004247:DNA / Q000737:chemistry*; D005260:Female; D020100:Hydrogels; D007249:Inflammation / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000276:Adjuvants, Immunologic; D020100:Hydrogels; D010455:Peptides; D004247:DNA
keywords: DNA; Drug delivery; Gene expression; Peptide; Self assembly