Department of Pediatric Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
Scand J Immunol. 2013 Jul;78(1):50-60. doi: 10.1111/sji.12065.
Adoptive cell transfer immunotherapy of malignant tumors has the problem of symbiosis between effector cells and tumor cells, a short in vivo residence time, and a poor killing efficiency of effector cells. Thus, releasing effector cells from the cancer immunosuppressive microenvironment and improving their effective time and functional status in vivo would seem to be ideal strategies for facilitating immunotherapy. Low-dose cyclophosphamide administration can effectively break immunotolerance by inhibiting regulatory T cells. In the present study, in order to verify whether the persistence, distribution and function of effector cells can be improved by inhibiting immunosuppressive microenvironment, low-dose cyclophosphamide was previously intraperitoneally injected into melanoma-bearing C57BL/6 mice, thereafter, CFSE-labeled cytotoxic T lymphocytes were transfused intravenously, and their effective time, distributive pattern, and killing efficiency in different groups were observed by measuring the fluorescence intensity and cell cycle of cytotoxic T lymphocytes distributed in various organs, in comparison with tumor growth. We found down-regulating Tregs in vivo can simultaneously reduce the levels of interleukin-10 and transforming growth factor-β. Migration and distribution of cytotoxic T lymphocytes in vivo was found to vary with time. Inhibition of immunotolerance can significantly improve the persistence, distribution, and function of cytotoxic T lymphocytes. Correspondingly, significantly higher secretion of perforin, granzyme B, IL-2, and IFN-γ in tumor tissues with decreased tumor growth was seen in the cyclophosphamide injection group than in the control group. Our study may provide useful information on the cyclophosphamide-mediated mechanism for facilitating tumor immunotherapy by inhibiting the immunosuppressive tumor microenvironment.
过继细胞转移免疫疗法治疗恶性肿瘤存在效应细胞与肿瘤细胞共生、体内居留时间短、效应细胞杀伤效率差等问题。因此，从肿瘤免疫抑制微环境中释放效应细胞，并提高其在体内的有效时间和功能状态，似乎是促进免疫治疗的理想策略。低剂量环磷酰胺通过抑制调节性 T 细胞可有效打破免疫耐受。在本研究中，为了验证抑制免疫抑制微环境是否可以提高效应细胞的持久性、分布和功能，我们先给荷瘤 C57BL/6 小鼠腹腔内注射低剂量环磷酰胺，然后静脉输注 CFSE 标记的细胞毒性 T 淋巴细胞，通过测量分布在不同器官的细胞毒性 T 淋巴细胞的荧光强度和细胞周期，观察其在不同组中的有效时间、分布模式和杀伤效率，并与肿瘤生长进行比较。我们发现体内下调 Tregs 可同时降低白细胞介素-10 和转化生长因子-β的水平。细胞毒性 T 淋巴细胞在体内的迁移和分布随时间而变化。免疫耐受的抑制可显著改善细胞毒性 T 淋巴细胞的持久性、分布和功能。相应地，与对照组相比，在环磷酰胺注射组中，肿瘤组织中穿孔素、颗粒酶 B、IL-2 和 IFN-γ 的分泌明显更高，肿瘤生长减少。我们的研究可能为通过抑制免疫抑制肿瘤微环境促进肿瘤免疫治疗的环磷酰胺介导机制提供有用信息。
