– 1,2-Dioleoyl-3(R)-trimethylammoniumpropane (R-DOTAP) is a cationic lipid and the more immunologically active isomer of DOTAP.Lipoplexes containing R-DOTAP and encapsulating siRNA targeting the gene encoding aromatase, CYP19A1, decrease aromatase activity in MCF-7 breast cancer cells.1 Vaccination with a peptide epitope from human papillomavirus (HPV) 16 protein E7 in R-DOTAP-containing liposomes induces IFN-? production by CD8+ T cells and tumor-infiltrating lymphocytes (TILs) and decreases tumor size in a murine cervical cancer model.2 Subcutaneous immunization with recombinant influenza B hemagglutinin using R-DOTAP as an adjuvant increases IL-2 and IFN-? production in CD4+ T cells isolated from mouse draining lymph nodes and spleen.