Yang K, Whalen BJ, Tirabassi RS, Selin LK, Levchenko TS, Torchilin VP, Kislauskis EH, Guberski DL. A DNA vaccine prime followed by a liposome-encapsulated protein boost confers enhanced mucosal immune responses and protection. J Immunol. 2008 May 01; 180(9):6159-67.