Epitope-based vaccination strategies designed to induce
tumor-specific CD8 CTL are being widely considered for
cancer immunotherapy. HLA-A2-transgenic mouse is a useful tool for measuring the CTL responses in vitro. However,
tumor vaccine development is required to address the variables that are not easily evaluated by in vitro assays. With the objective of extending the usage of A2-tansgenic mouse in
vaccine efficacy assay, here, we established a B16 tumor cell line coexpressing
HLA-A*0201/H-2Kb chimeric gene and a polyepitope construct based on the use of a mammalian expression vector pIRES. The value as a tool for evaluating the antitumor efficacy in vitro as well as in experimental
tumor challenge model in vivo has been tested. We found that priming with the polyepitope construct and boosting with the mixture of
peptide in A2-transgenic mice resulted in: (1) CTL responses not only against the
peptide-sensitized T2 and SW480 cell lines but also the non-sensitized reconstructed B16 cell line; (2) expression of
HLA-A*0201/H-2Kb chimeric gene and polyepitopes by B16 led to its rejection by immunized A2-transgenic mice. These data established that the reconstructed B16 cell line stably expressed and efficiently presented the HCC-derived CTL
epitopes, making B16 based
melanoma suitable for the evaluation of the antitumor efficacy of immune responses to these
epitopes. Collectively, these data indicate that the use of this method allows for directly testing of
HLA-A2 restricted
epitope immunogenicity in the A2-transgenic mice.