Abstract
For establishment of efficient cancer immunotherapy, antigen carriers that can deliver antigen to immunocompetent cells, activate these cells and induce antigen-specific cellular immunity are required. We synthesized functional polymers to induce membrane fusion in response to weakly acidic pH and modified these polymers onto antigen-loaded liposomes to develop antigen delivery systems for induction of cellular immunity efficiently. pH-sensitive polymer-modified liposomes were taken up by dendritic cells efficiently and achieved cytoplasmic delivery of antigenic proteins via membrane fusion with endosomal membrane responding to weakly acidic pH in endosomes. In addition, inclusion of adjuvant molecules and bioactive polysaccharide-based pH-sensitive polymers into antigen-loaded liposomes induced strong antitumor effects in tumor-bearing mice.
