Induction of CD8+ T-cell responses against subunit antigens by the novel cationic liposomal CAF09 adjuvant

Vaccine. 2014 Jun 30;32(31):3927-35. doi: 10.1016/j.vaccine.2014.05.050. Epub 2014 May 28.


Vaccines inducing cytotoxic T-cell responses are required to achieve protection against cancers and intracellular infections such as HIV and Hepatitis C virus. Induction of CD8+ T cell responses in animal models can be achieved by the use of viral vectors or DNA vaccines but so far without much clinical success. Here we describe the novel CD8+ T-cell inducing adjuvant, cationic adjuvant formulation (CAF) 09, consisting of dimethyldioctadecylammonium (DDA)-liposomes stabilized with monomycoloyl glycerol (MMG)-1 and combined with the TLR3 ligand, Poly(I:C). Different antigens from tuberculosis (TB10.3, H56), HIV (Gag p24), HPV (E7) and the model antigen ovalbumin were formulated with CAF09 and administering these vaccines to mice resulted in a high frequency of antigen-specific CD8+ T cells. CAF09 was superior in its ability to induce antigen-specific CD8+ T cells as compared to other previously described CTL-inducing adjuvants, CAF05 (DDA/trehalose dibehenate (TDB)/Poly(I:C)), Aluminium/monophosphoryl lipid-A (MPL) and Montanide/CpG/IL-2. The optimal effect was obtained when the CAF09-adjuvanted vaccine was administered by the i.p. route, whereas s.c. administration primed limited CD8+ T-cell responses. The CD4+ T cells induced by CAF09 were mainly of an effector-memory-like phenotype and the CD8+ T cells were highly cytotoxic. Finally, in a mouse therapeutic skin tumor model, the HPV-16 E7 antigen formulated in CAF09 significantly reduced the growth of already established subcutaneous E7-expressing TC-1 tumors in 38% of the mice and in a corresponding prophylactic model 100% of the mice were protected. Thus, CAF09 is a potent new adjuvant which is able to induce CD8+ T-cell responses against several antigens and to enhance the protective efficacy of an E7 vaccine both in a therapeutic and in a prophylactic tumor model.

Keywords: Adjuvant; CAF09; CD8+ T cells; CTL; Cationic liposome; Vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / pharmacology*
  • Animals
  • Antigens / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • Cations / pharmacology
  • Female
  • Immunity, Cellular
  • Liposomes / pharmacology*
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Inbred DBA
  • Papillomavirus E7 Proteins / immunology
  • Poly I-C / pharmacology*
  • Skin Neoplasms / immunology
  • Skin Neoplasms / virology
  • T-Lymphocytes, Cytotoxic / immunology


  • Adjuvants, Immunologic
  • Antigens
  • Cations
  • Liposomes
  • Papillomavirus E7 Proteins
  • oncogene protein E7, Human papillomavirus type 16
  • Poly I-C