Fujinami Norihiro, Yoshikawa Toshiaki, Sawada Yu, Shimomura Manami, Iwama Tatsuaki, Sugai Shiori, Kitano Shigehisa, Uemura Yasushi, Nakatsura Tetsuya
Division of Cancer Immunotherapy, Exploratory Oncology Research & Clinical Trial Center National Cancer Center, Kashiwa, Chiba, Japan.
Research Institute for Biomedical Sciences, Tokyo University of Science, Japan.
Biochem Biophys Rep. 2016 Feb 19;5:482-491. doi: 10.1016/j.bbrep.2016.02.010. eCollection 2016 Mar.
The clinical efficacy of cancer peptide vaccine therapy is insufficient. To enhance the anti-tumor effect of peptide vaccine therapy, we combined this therapy with an anti-CD4 mAb (GK1.5), which is known to deplete CD4 cells, including regulatory T cells (Tregs).
To determine the treatment schedule, the number of lymphocyte subsets in the peripheral blood of mice was traced by flow cytometry after administration of anti-CD4 mAb. The ovalbumin (OVA) peptide vaccine was injected intradermally and anti-CD4 mAb was administered intraperitoneally into C57BL/6 mice at different schedules. We evaluated the enhancement of OVA peptide-specific cytotoxic T lymphocyte (CTL) induction in the combination therapy using the ELISPOT assay, CD107a assay, and cytokine assay. We then examined the metastasis inhibitory effect by OVA peptide vaccine therapy in combination with anti-CD4 mAb against OVA-expressing thymoma (EG7) in a murine liver metastatic model.
We showed that peptide-specific CTL induction was enhanced by the peptide vaccine in combination with anti-CD4 mAb and that the optimized treatment schedule had the strongest induction effect of peptide-specific CTLs using an IFN-γ ELISPOT assay. We also confirmed that the CD107a cells secreted perforin and granzyme B and the amount of IL-2 and TNF produced by these CTLs increased when the peptide vaccine was combined with anti-CD4 mAb. Furthermore, metastasis was inhibited by peptide vaccines in combination with anti-CD4 mAb compared to peptide vaccine alone in a murine liver metastatic model.
The use of anti-CD4 mAb in combination with the OVA peptide vaccine therapy increased the number of peptide-specific CTLs and showed a higher therapeutic effect against OVA-expressing tumors. The combination with anti-CD4 mAb may provide a new cancer vaccine strategy.
癌症肽疫苗疗法的临床疗效不足。为增强肽疫苗疗法的抗肿瘤效果，我们将这种疗法与抗CD4单克隆抗体（GK1.5）联合使用，已知该抗体可耗尽包括调节性T细胞（Tregs）在内的CD4细胞。
为确定治疗方案，在给予抗CD4单克隆抗体后，通过流式细胞术追踪小鼠外周血中淋巴细胞亚群的数量。将卵清蛋白（OVA）肽疫苗皮内注射，并以不同方案将抗CD4单克隆抗体腹腔注射到C57BL/6小鼠体内。我们使用ELISPOT分析、CD107a分析和细胞因子分析评估联合疗法中OVA肽特异性细胞毒性T淋巴细胞（CTL）诱导的增强情况。然后，我们在小鼠肝转移模型中研究了OVA肽疫苗疗法与抗CD4单克隆抗体联合对表达OVA的胸腺瘤（EG7）的转移抑制作用。
我们发现，肽疫苗与抗CD4单克隆抗体联合可增强肽特异性CTL的诱导，并且使用IFN-γ ELISPOT分析，优化的治疗方案对肽特异性CTL的诱导作用最强。我们还证实，当肽疫苗与抗CD4单克隆抗体联合时，CD107a细胞分泌穿孔素和颗粒酶B，并且这些CTL产生的IL-2和TNF量增加。此外，在小鼠肝转移模型中，与单独使用肽疫苗相比，肽疫苗与抗CD4单克隆抗体联合可抑制转移。
抗CD4单克隆抗体与OVA肽疫苗疗法联合使用增加了肽特异性CTL的数量，并对表达OVA的肿瘤显示出更高的治疗效果。与抗CD4单克隆抗体联合可能提供一种新的癌症疫苗策略。
