This invention relates to compositions, and related methods, of synthetic nanocarriers that target sites of action in cells, such as antigen presenting cells (APCs), and comprise immunomodulatory agents that dissociate from the synthetic nanocarriers in a pH sensitive manner. Also disclosed are compositions and methods relating to synthetic nanocarriers that encapsulate labile immunomodulatory agents that dissociate from the synthetic nanocarriers in a pH sensitive manner.
