Increasing cellular immunogenicity to peptide-based vaccine candidates using a fluorocarbon antigen delivery system

Traditionally, synthetic peptide vaccines for infectious diseases and cancer require adjuvants to achieve optimal immunogenicity. Here we describe a novel method of peptide modification using a fluorocarbon chain which can substantially increase peptide-specific cellular immune responses in the absence of adjuvant. We demonstrate that fluorocarbon-modified peptides (fluoropeptides) derived from HIV, influenza and hepatitis C virus can significantly increase interferon gamma ELISpot responses against cytotoxic and T-helper epitopes compared to unmodified peptides or lipopeptides in mice. Increases in both T-helper1 and T-helper2 cytokines are observed. Fluoropeptides show enhanced ability of the antigen to persist at the site of administration and persistence is associated with a prolonged and elevated immune response. Additionally we demonstrate that fluoropeptides have increased proteolytic resistance thereby potentially supporting their increased half-life in vivo. Fluorocarbon-modification of peptides provides a valuable tool for increasing cellular immunogenicity of vaccines for infectious diseases and cancer without requirement for traditional adjuvants.