Aim: We investigated cellular and protective immune responses in mice vaccinated with recombinant HER2 extracellular subdomains.
Materials & methods: Balb/C mice were immunized with recombinant full HER2 extracellular domain and subdomain proteins. Humoral and cellular immune response and antitumor effect was evaluated using a syngeneic mice tumor model.
Results: All recombinant proteins induced secretion of IL-4 and particularly IFN-γ and IL-17 cytokines. Challenging of immunized mice with stable 4T1-HER2 transfected cells resulted in partial but significant tumor growth inhibition in all groups of mice particularly those immunized with fHER2-ECD together with CPG.
Conclusion: Our results suggest that the recombinant HER2-ECD subdomains induce mainly Th1 and Th17 responses, which seem to contribute to tumor growth inhibition in syngeneic mice.
Keywords: HER2; breast cancer; cytokine; protein immunization; tumor challenge.