CHARACTERIZATION OF TCR Vβ RESPONSE TO CANCER ANTIGEN PEPTIDE

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We have been investigating the immune response of cytotoxic T cells (CTL) with their TCR Vβ repertoire in tumor specific manner. In this study, we investigated the CTL response to synthetic peptide compared with their TCR Vβ repertoire. Synthetic peptide-specific CTLs were generated with in vitro stimulation by peptide-pulsed dendritic cells. When T cells were stimulated with synthetic MUC1 peptide-pulsed DCs, TCR Vβ 1, 2, 3, 7.1 and 17 positive T cells increased after in vitro stimulation. After several injection of MUC1 peptide-pulsed dendritic cells into cancer patients as vaccine, TCR Vβ 1, 2, 3, 7.1 and 17 positive T cells also increased in their peripheral blood. These T cells demonstrated the high cytolytic reactivity against MUC1 positive cancer cell, but not against MUC1 negative cancer cells. IFNγ release from CTLs also increased after vaccination. HLA tetramer could not detect the peptide-specific CTL precursor in vaccinated patients.In conclusion, it was demonstrated that in vivo CTL precursor could be measurable by their TCR Vβ repertoire instead of the examination with common HLA-tetramer staining which is expensive and difficult to make. TCR Vβ repertoire analysis would be useful for the analysis of in vivo CTL precursor in active immunotherapy.