Compositions and methods for enhancing immune responses mediated by antigen-presenting cells

Molecular adjuvants are disclosed comprising an antigen presenting cell-targeting ligand linked to an immunogen, e.g. tumor associated antigens, bacterial or viral antigens. The ligand and the immunogen are linked via a cleavable linker such as a protease-sensitive oligopeptide, to facilitate processing of the adjuvant by the antigen presenting cell. Methods are disclosed for delivery of these molecular adjuvants to patients, resulting in the transduction of activating signals to the targeted antigen presenting cell, thereby enhancing the immune response to the co-delivered immunogen.