Dimethyldioctadecylammonium (DDA) is a cationic amphipathic lipid. DDA liposomes containing an Ag85B-ESAT-6 antigen induce antigen deposition at an intramuscular or subcutaneous injection site in mice, increasing immune cell exposure to the antigen. In a guinea pig model of M. tuberculosis infection, spleen bacterial load is reduced and lung and spleen lesion numbers are decreased when the mycobacterial lipid antigens Ac2SGL and PIM2 are administered in liposomes comprised of DDA and a synthetic analog of the mycobacterial cord factor trehalose 6,6-dibehenate (TDB). DDA has also been used in the study of lipid bilayer dynamics.