PLoS ONE (Jan 2017)

Synthetic melanin bound to subunit vaccine antigens significantly enhances CD8+ T-cell responses.

  • Antoine F Carpentier,
  • Frédéric Geinguenaud,
  • Thi Tran,
  • Floraly Sejalon,
  • Antoine Martin,
  • Laurence Motte,
  • Eric Tartour,
  • Claire Banissi

DOI
https://doi.org/10.1371/journal.pone.0181403
Journal volume & issue
Vol. 12, no. 7
p. e0181403

Abstract

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Cytotoxic T-lymphocytes (CTLs) play a key role in immunity against cancer; however, the induction of CTL responses with currently available vaccines remains difficult. Because several reports have suggested that pigmentation and immunity might be functionally linked, we investigated whether melanin can act as an adjuvant in vaccines. Short synthetic peptides (8-35 amino acids long) containing T-cell epitopes were mixed with a solution of L-Dopa, a precursor of melanin. The mixture was then oxidized to generate nanoparticles of melanin-bound peptides. Immunization with melanin-bound peptides efficiently triggered CTL responses in mice, even against self-antigens and at a very low dose of peptides (microgram range). Immunization against a tumor antigen inhibited the growth of established tumors in mice, an effect that was abrogated by the depletion of CD8+ lymphocytes. These results demonstrate the efficacy of melanin as a vaccine adjuvant.