Study of Ridostin Pro and Poly(I:C) as adjuvants for cancer vaccine on the E.G7-OVA model

Background. Adjuvant is necessary for enhancing the efficacy of cancer peptide vaccines. Our previous work has demonstrated the efficacy of TRL-3 agonists, which include Poly(I:C) and Ridostin Pro, as part of peptide neoantigen vaccines against murine melanoma B16-F10.

Aim. To evaluate the antitumor efficacy of Ridostin Pro or Poly(I:C) against murine lymphoma E.G7-OVA.

Materials and methods. The study was performed on C57Bl / 6 mice with subcutaneously transplanted E.G7-OVA lymphoma containing the complete chicken ovalbumin sequence. The antitumor effects of Ridostin Pro and Poly(I:C) were evaluated in monotherapy as well as in vaccines containing chicken ovalbumin in addition to the adjuvant. The antitumor effect of Ridostin Pro and Poly(I:C) was evaluated when used in different vaccination regimens: in one case treatment was started after tumour transplantation and in the other case before tumour transplantation. The criteria of antitumor response were inhibition of tumour growth, increased survival of mice and cure.

Results. Ridostin Pro and Poly(I:C) both as part of the vaccine and when administered without ovalbumin increased the percentage of tumour growth inhibition and survival of mice with E.G7-OVA lymphoma. In a regime where  vaccination with ovalbumin and Ridostin Pro or Poly(I:C) was started before tumour transfection, a complete cure of the mice was shown.

Conclusion. Ridostin Pro and Poly(I:C) enhance the antitumor effect of a peptide vaccine against E.G7-OVA lymphoma.

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