title: Trp2 peptide vaccine adjuvanted with (R)-DOTAP inhibits tumor growth in an advanced melanoma model.
abstract: Previously we have shown cationic lipid (R)-DOTAP as the immunologically active enantiomer of the DOTAP racemic mixture, initiating complete tumor regression in an exogenous antigen model (murine cervical cancer model). Here, we investigate the use of (R)-DOTAP as an efficacious adjuvant delivering an endogenous antigen in an aggressive murine solid tumor melanoma model. (R)-DOTAP/Trp2 peptide complexes showed decreasing size and charge with increasing peptide concentration, taking a rod shape at highest concentrations. The particles were stable for 2 weeks at 4 °C. A dose of 75 nmol of Trp2 (formulated in (R)-DOTAP) was able to show statistically significant tumor growth delay compared to lower doses of 5 and 25 nmol, which were no different than untreated tumors. (R)-DOTAP/Trp2 (75 nmol) treated mice also showed increased T cell IFN-γ secretion after restimulation with Trp2, as well as CTL activity in vivo. This vaccination group also showed the highest population of functionally active tumor-infiltrating lymphocytes, indicated by IFN-γ secretion after restimulation with Trp2. Thus, (R)-DOTAP has shown the ability to break tolerance as an adjuvant. Its activity to enhance immunogenicity of other tumor associated antigens should be studied further.
authors.affiliation: Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Vasievich
authors.forename: Srinivas
authors.initials: S
authors.lastname: Ramishetti
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Leaf
authors.initials: L
authors.lastname: Huang
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry*; D005260:Female; D007167:Immunotherapy / Q000379:methods*; D007371:Interferon-gamma / Q000378:metabolism; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology / Q000378:metabolism; D008546:Melanoma, Experimental / Q000628:therapy*; D008565:Membrane Proteins / Q000276:immunology* / Q000627:therapeutic use; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D009368:Neoplasm Transplantation; D010316:Particle Size; D010446:Peptide Fragments / Q000276:immunology* / Q000627:therapeutic use; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D059016:Tumor Microenvironment / Q000276:immunology; D022223:Vaccines, Subunit / Q000276:immunology / Q000627:therapeutic use
chemical_list: D000276:Adjuvants, Immunologic; D019496:Cancer Vaccines; D005229:Fatty Acids, Monounsaturated; D008565:Membrane Proteins; D010446:Peptide Fragments; D000644:Quaternary Ammonium Compounds; D022223:Vaccines, Subunit; C500290:peptide SVYDFFVWL; D007371:Interferon-gamma; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane