CHARACTERIZATION OF TCR Vβ RESPONSE TO CANCER ANTIGEN PEPTIDE

我们一直在以肿瘤特异性方式研究细胞毒性T细胞（CTL）及其TCR Vβ库的免疫反应。在本研究中，我们研究了CTL对合成肽的反应，并与它们的TCR Vβ库进行了比较。合成的肽特异性CTL通过肽脉冲的树突状细胞体外刺激产生。当用合成MUC1肽致敏的DC刺激T细胞时，TCR Vβ 1、2、3、7.1和17阳性T细胞在体外刺激后增加。肿瘤患者多次注射MUC1肽致敏的树突状细胞作为疫苗后，外周血中TCR Vβ 1、2、3、7.1和17阳性T细胞也增加。这些T细胞表现出对MUC1阳性癌细胞的高细胞溶解反应性，但对MUC1阴性癌细胞没有。接种后，CTL释放的IFNγ也增加。结论：HLA四聚体染色法不能检测出疫苗免疫后患者体内的肽特异性CTL前体，因此可以通过TCR Vβ库来检测体内CTL前体，而不需要用昂贵且难以制备的普通HLA四聚体染色法来检测。TCRV β库的分析有助于体内CTL前体的分析。

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.