Pan Ping-Ying, Li Yu, Li Qingsheng, Gu Pedi, Martinet Olivier, Thung Swan, Chen Shu-Hsia
Carl C Icahn Institute for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
Cancer Immunol Immunother. 2004 Jan;53(1):17-25. doi: 10.1007/s00262-003-0417-4. Epub 2003 Sep 2.
Proper antigen presentation is paramount to the induction of effective and persistent antitumor immune responses. In a murine model of hepatic metastasis of colon cancer, we found that the numbers of in situ mature dendritic cells (DCs) and macrophages in tumor-infiltrating leukocytes (TILs) were significantly increased in mice treated with the combination therapy of herpes simplex virus thymidine kinase, interleukin 2, and GM-CSF genes when compared with control groups without GM-CSF treatment. Significantly higher levels of IFN-gamma, MIP-1 alpha, mIL-12, and GM-CSF were detected in the tumor after the combination therapy. T cells isolated from the combination therapy-treated mice exhibited higher ex vivo direct CTL activity than those from other treatment groups. Antigen-presenting cells (APCs) enriched from the TILs and liver of the combination therapy-treated mice induced higher levels of proliferation by the splenocytes from long-term surviving mice that had been cured of tumors at early time points (days 4 and 7) whereas significant APC activity was only observed in the spleen at the latter time point (day 7, 14) after the combination therapy. In contrast, APCs isolated from tk or tk + IL-2-treated mice did not induce any significant proliferation. Subcutaneous injection of fluorescence-labeled latex microspheres followed by the combination therapy showed a similar sequential trafficking of microspheres, day 4 after the combination therapy to tumor and day 14 to spleen. The results suggest that APCs recruited by intratumoral gene delivery of GM-CSF can capture antigens, mature to a stage suitable for antigen presentation, and subsequently migrate to the spleen where they can efficiently stimulate antigen-specific T cells.
适当的抗原呈递对于诱导有效的持久抗肿瘤免疫反应至关重要。在结肠癌肝转移的小鼠模型中，我们发现，与未进行GM-CSF治疗的对照组相比，接受单纯疱疹病毒胸苷激酶、白细胞介素2和GM-CSF基因联合治疗的小鼠肿瘤浸润白细胞（TILs）中原位成熟树突状细胞（DCs）和巨噬细胞的数量显著增加。联合治疗后，在肿瘤中检测到显著更高水平的干扰素-γ、巨噬细胞炎性蛋白-1α、小鼠白细胞介素-12和GM-CSF。从联合治疗组小鼠中分离出的T细胞在体外表现出比其他治疗组更高的直接细胞毒性T淋巴细胞（CTL）活性。从联合治疗组小鼠的TILs和肝脏中富集的抗原呈递细胞（APC）能诱导早期（第4天和第7天）治愈肿瘤的长期存活小鼠的脾细胞产生更高水平的增殖，而在联合治疗后的后期（第7天、第14天），仅在脾脏中观察到显著的APC活性。相比之下，从单纯疱疹病毒胸苷激酶或单纯疱疹病毒胸苷激酶+白细胞介素2治疗组小鼠中分离出的APC未诱导任何显著的增殖。皮下注射荧光标记的乳胶微球后进行联合治疗，结果显示微球的转运顺序相似，联合治疗后第4天微球转移至肿瘤，第14天转移至脾脏。结果表明，通过瘤内递送GM-CSF招募的APC能够捕获抗原，成熟至适合抗原呈递的阶段，随后迁移至脾脏，在脾脏中它们能够有效刺激抗原特异性T细胞。
