The connection of innate and adaptive anti-cancer immunity

卡介苗（BCG）是膀胱内治疗原位癌和非肌肉侵袭性、非转移性人尿路上皮癌的标准护理。尽管对这种免疫治疗的反应性被认为与(a)大量的体细胞突变和(b)大量的肿瘤浸润淋巴细胞有关，但最近对抑制性免疫受体及其配体在肿瘤逃避中所起作用的发现可能为卡介苗有效性的局限性提供了新的见解，并为免疫治疗提供了新的靶点。本研究采用侵袭性、生物发光原位膀胱癌模型，即转染荧光素酶（MB49(luc)）的MB49肿瘤细胞，研究抗PD-L1抗体avelumab的抗肿瘤作用。MB49（luc）小鼠肿瘤细胞在膀胱粘膜壁上形成多灶性肿瘤，使人联想到非肌肉侵袭性、非转移性尿路上皮癌。MB49（luc）膀胱肿瘤患者PD-L1表达高度阳性，给予avelumab可诱导显著的抗肿瘤作用（p0.05）。这些抗肿瘤作用更多地依赖于CD4而不是CD8 T细胞的存在，这是由体内免疫细胞消耗确定的。研究结果表明，在膀胱肿瘤模型中，阻断免疫抑制的PD-1/PD-L1复合物释放局部适应性免疫应答，进而降低肿瘤生长。该膀胱肿瘤模型可用于进一步确定宿主抗肿瘤免疫机制，并评估免疫疗法联合治疗原位癌和非肌肉侵袭性、非转移性尿路上皮癌，为后续临床研究提供依据。靶向递送IL-12可能会使这种细胞因子成为一种更安全、更有效的癌症治疗药物。我们描述了一种新的免疫细胞因子，nhs - IL-12，由两个IL-12分子融合到肿瘤坏死靶向人IgG1 （NHS76）组成。人IgG1片段的加入使得nhs - IL-12的血浆半衰期比重组IL-12更长，并且在体内选择性靶向小鼠肿瘤。利用人外周血单个核细胞（PBMCs）和灵长类动物体内研究进行的体外实验数据表明，免疫细胞在免疫细胞因子处理后产生的ifn - γ减少，这表明与单独使用重组IL-12相比，重组IL-12的毒性有所改善。在三种小鼠肿瘤模型中，nhs - IL-12的抗肿瘤作用均优于重组IL-12。利用免疫细胞亚群消耗抗体、流式细胞术方法、体外细胞毒性和ELISA检测的机制研究都表明，nhs - il -12的抗肿瘤作用主要依赖于CD8+ T细胞，可能是il -12介导的。将nhs - il - 12治疗与癌症疫苗、放疗或化疗相结合，比单独治疗产生更大的抗肿瘤效果。这些临床前研究结果为该免疫细胞因子的临床试验提供了理论依据，无论是作为单一药物还是与疫苗、放疗和化疗联合使用。

--- Bacillus Calmette-Guerin (BCG) is the standard of care for intravesical therapy for carcinoma in situ and non-muscle invasive, non-metastatic human urothelial carcinoma. Although the responsiveness to this immunotherapeutic is believed to be linked with (a) a high number of somatic mutations and (b) a large number of tumor-infiltrating lymphocytes, recent findings of the roles that inhibitory immune receptors and their ligands play in tumor evasion may provide insights into the limitations of the effectiveness of BCG and offer new targets for immune-based therapy. In this study, an aggressive, bioluminescent orthotopic bladder cancer model, MB49 tumor cells transfected with luciferase (MB49(luc)), was used to study the antitumor effects of avelumab, an antibody to PD-L1. MB49(luc) murine tumor cells form multifocal tumors on the mucosal wall of the bladder reminiscent of non-muscle invasive, non-metastatic urothelial carcinomas. MB49(luc) bladder tumors are highly positive for the expression of PD-L1, and avelumab administration induced significant (P 0.05) antitumor effects. These antitumor effects were more dependent on the presence of CD4 than CD8 T cells, as determined by in vivo immune cell depletions. The findings suggest that in this bladder tumor model, interruption of the immune-suppressive PD-1/PD-L1 complex releases a local adaptive immune response that, in turn, reduces tumor growth. This bladder tumor model can be used to further identify host antitumor immune mechanisms and evaluate combinations of immune-based therapies for carcinoma in situ and non-muscle invasive, non-metastatic urothelial carcinoma, to provide the rationale for subsequent clinical studies. --- Targeted delivery of IL-12 might turn this cytokine into a safer, more effective cancer therapeutic. We describe a novel immunocytokine, NHS-IL12, consisting of two molecules of IL-12 fused to a tumor necrosis-targeting human IgG1 (NHS76). The addition of the human IgG1 moiety resulted in a longer plasma half-life of NHS-IL12 than recombinant IL-12, and a selective targeting to murine tumors in vivo. Data from both in vitro assays using human peripheral blood mononuclear cells (PBMCs) and in vivo primate studies showed that IFN-gamma production by immune cells is attenuated following treatment with the immunocytokine, suggesting an improved toxicity profile than seen with recombinant IL-12 alone. NHS-IL12 was superior to recombinant IL-12 when evaluated as an anti-tumor agent in three murine tumor models. Mechanistic studies utilizing immune cell subset-depleting antibodies, flow cytometric methods, and in vitro cytotoxicity and ELISA assays all indicated that the anti-tumor effects of NHS-IL12 were primarily CD8+ T cell-dependent and likely IL-12-mediated. Combining NHS-IL12 treatment with a cancer vaccine, radiation, or chemotherapy resulted in greater anti-tumor effects than each individual therapy alone. These preclinical findings provide a rationale for the clinical testing of this immunocytokine, both as a single agent and in combination with vaccines, radiation and chemotherapy.