Therapy of established B16-F10 melanoma tumors by a single vaccination of CTL/T helper peptides in VacciMax

J Transl Med. 2007 Apr 23;5:20. doi: 10.1186/1479-5876-5-20.

Abstract

Background: Melanoma tumors are known to express antigens that usually induce weak immune responses of short duration. Expression of both tumor-associated antigens p53 and TRP2 by melanoma cells raises the possibility of simultaneously targeting more than one antigen in a therapeutic vaccine. In this report, we show that VacciMax (VM), a novel liposome-based vaccine delivery platform, can increase the immunogenicity of melanoma associated antigens, resulting in tumor elimination.

Methods: C57BL/6 mice bearing B16-F10 melanoma tumors were vaccinated subcutaneously 6 days post tumor implantation with a mixture of synthetic peptides (modified p53: 232-240, TRP-2: 181-188 and PADRE) and CpG. Tumor growth was monitored and antigen-specific splenocyte responses were assayed by ELISPOT.

Results: Vaccine formulated in VM increased the number of both TRP2- and p53-specific IFN-gamma producing splenocytes following a single vaccination. Vaccine formulated without VM resulted only in enhanced IFN-gamma producing splenocytes to one CTL epitopes (TRP2:180-188), suggesting that VM overcomes antigen dominance and enhances immunogenicity of multiple epitopes. Vaccination of mice bearing 6-day old B16-F10 tumors with both TRP2 and p53-peptides formulated in VM successfully eradicated tumors in all mice. A control vaccine which contained all ingredients except liposomes resulted in eradication of tumors in no more than 20% of mice.

Conclusion: A single administration of VM is capable of inducing an effective CTL response to multiple tumor-associated antigens. The responses generated were able to reject 6-day old B16-F10 tumors.

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / immunology
  • Cancer Vaccines / immunology*
  • Female
  • Interferon-gamma / biosynthesis
  • Lymphocyte Count
  • Melanoma, Experimental / immunology*
  • Melanoma, Experimental / prevention & control
  • Melanoma, Experimental / therapy*
  • Mice
  • Mice, Inbred C57BL
  • Peptides / immunology*
  • Spleen / cytology
  • Spleen / immunology
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Helper-Inducer / immunology*
  • Vaccination / instrumentation*

Substances

  • Cancer Vaccines
  • Peptides
  • Interferon-gamma