Fluorinated Lipids Conjugated to Peptide Antigens do not Induce Immune Responses Against Cervical Cancer

Background: Despite the high safety profile of peptide-based vaccines over conventional counterparts, the inability of small peptides to produce a strong immune response represents the main obstacle for the development of these types of vaccines. Introducing a self-adjuvanting moiety such as fluorinated lipids can overcome this problem. We have recently demonstrated that fluorinated lipids can induce humoral immune responses against associated peptide antigen; however, the ability of these amphiphilic lipids to elicit a desired cellular immune response to eradicate tumor cells has not been yet investigated. Methods: An in vivo assay was employed to evaluate the ability of fluorinated lipopeptides to eradicate tumor in mouse model. In this study, the double conjugation technique was used to synthesise fluorinated and non-fluorinated lipids conjugated to two cytotoxic T-lymphocyte (CTL) peptide epitopes derived from the E6 and E7 proteins of human papilloma virus (HPV). Results: Mice implanted with TC-1 tumor cells and immunised with fluorinated lipopeptides did not mount a strong cellular immune response, thus did not eradicate the tumors. In contrast, 60% of mice immunised with the non-fluorinated lipopeptide cleared the TC-1 tumor. Conclusion: This result indicated that fluorinated lipids lack of the ability to stimulate a strong cellular immunity despite their ability to elicit significant humoral immune responses.