Department of Hepato-Biliary-Pancreatic and Pediatric Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
Department of Hepato-Biliary-Pancreatic and Pediatric Surgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
J Surg Res. 2023 Sep;289:190-201. doi: 10.1016/j.jss.2023.03.042. Epub 2023 May 2.
Tumor-infiltrating cells play an important role in tumor immunology, and tumor-infiltrating lymphocytes (TILs) are critical in antitumor reaction related to immune checkpoint inhibition targeting programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1).
In nude mice, which are immune deficient because they lack T cells, and inbred A/J mice, which are syngeneic to neuroblastoma cells (Neuro-2a) and have normal T cell function, we investigated the importance of T lymphocytes in immune checkpoint inhibition in mouse neuroblastoma and analyzed the immune cells in the tumor microenvironment. Then, we subcutaneously injected mouse Neuro-2ainto nude mice and A/J mice, administered anti-PD-1 and anti-PD-L1 antibodies by intraperitoneal injection, and evaluated tumor growth. At 16 d after Neuro-2a cells injection, mice were euthanized, tumors and spleens were harvested, and immune cells were analyzed by flow cytometry.
The antibodies suppressed tumor growth in A/J but not in nude mice. The co-administration of antibodies did not affect regulatory T cells (culster of differentiation [CD]4CD25FoxP3 cells) or activated CD4 lymphocytes (expressing CD69). No changes in activated CD8 lymphocytes (expressing CD69) were observed in spleen tissue. However, increased infiltration of activated CD8 TILs was seen in tumors weighing less than 300 mg, and the amount of activated CD8 TILs was negatively correlated with tumor weight.
Our study confirms that lymphocytes are essential for the antitumor immune reaction induced by blocking PD-1/PD-L1 and raises the possibility that promoting the infiltration of activated CD8 TIL into tumors may be an effective treatment for neuroblastoma.
浸润肿瘤的细胞在肿瘤免疫学中发挥重要作用，肿瘤浸润淋巴细胞（TILs）在针对程序性细胞死亡蛋白 1（PD-1）和程序性细胞死亡配体 1（PD-L1）的免疫检查点抑制的抗肿瘤反应中至关重要。
在缺乏 T 细胞的免疫缺陷裸鼠和与神经母细胞瘤细胞（Neuro-2a）同系并且具有正常 T 细胞功能的近交 A/J 小鼠中，我们研究了 T 淋巴细胞在小鼠神经母细胞瘤免疫检查点抑制中的重要性，并分析了肿瘤微环境中的免疫细胞。然后，我们将小鼠神经母细胞瘤细胞（Neuro-2a）皮下注射到裸鼠和 A/J 小鼠中，通过腹腔注射给予抗 PD-1 和抗 PD-L1 抗体，并评估肿瘤生长情况。在注射 Neuro-2a 细胞后 16d，处死小鼠，采集肿瘤和脾脏，并通过流式细胞术分析免疫细胞。
抗体抑制了 A/J 小鼠的肿瘤生长，但对裸鼠没有影响。抗体联合使用不会影响调节性 T 细胞（分化群 [CD]4CD25FoxP3 细胞）或激活的 CD4 淋巴细胞（表达 CD69）。在脾脏组织中，未观察到激活的 CD8 淋巴细胞（表达 CD69）的变化。然而，在肿瘤重量小于 300mg 时，观察到浸润的激活的 CD8 TIL 增加，并且激活的 CD8 TIL 的数量与肿瘤重量呈负相关。
本研究证实了淋巴细胞对于阻断 PD-1/PD-L1 诱导的抗肿瘤免疫反应至关重要，并提出了促进激活的 CD8 TIL 浸润肿瘤的可能性，这可能是神经母细胞瘤的有效治疗方法。
