The connection of innate and adaptive anti-cancer immunity

免疫细胞因子NHS-IL 12作为潜在的癌症治疗剂：通过将人IL-12异源二聚体基因融合到NHS 76抗体重链的C-末端来工程化肿瘤靶向白细胞介素（IL）-12免疫细胞因子NHS-IL 12。NHS 76是一种完全人源抗体，其特异性结合DNA/组蛋白，从而靶向体内肿瘤。该抗体的放射性标记嵌合形式已显示出选择性靶向人类肿瘤，并已在中国被批准用于肺癌的治疗。为了使NHS-muIL 12在鼠模型中的亚细胞定位可视化，我们将荷瘤小鼠皮下（s.c.）用NHS-IL 12进行了细胞毒性试验，观察到肿瘤细胞核中的不同肿瘤靶向和染色。这种免疫细胞因子在三种不同肿瘤模型（LLC、MC 38和B16）的抗肿瘤研究中优于等摩尔剂量的重组鼠IL-12（rMuIL-12）。研究发现NHS-muIL 12可增加血清IFN-γ水平，上调DC上MHC I类蛋白表达，并诱导CD 49 b+自然杀伤（NK）细胞和CD 8 + T细胞增殖，所有这些均呈剂量依赖性。免疫细胞亚群消耗研究证实，NHS-muIL 12的抗肿瘤作用涉及CD 8+细胞和NK细胞，这与IL-12的已知作用机制一致。治愈MC 38肿瘤的小鼠显示出对肿瘤再攻击的抵抗力，并显示出持久的TAA特异性CTL记忆。观察到的NHS-muIL-12相对于rMuIL-12的这种增强的功效可能源于免疫细胞因子的更有利的药代动力学性质及其肿瘤结合能力。NHS-IL 12也已在临床前与几种标准护理疗法联合使用。当NHS-IL 12与（a）分次放射（刘易斯肺癌）、（B）TKI舒尼替尼（Renca肾癌）和（c）多西他赛（MC 38结肠癌模型）组合使用时，与单独使用任一药剂相比，我们已经显示出统计学上增强的抗肿瘤作用。NHS-IL 12的I期研究正在进行中。低剂量saracatinib对CD 8 + T细胞的免疫增强作用可能在与疫苗联合使用时提供更好的病原体或癌症保护。抑制TGF-β 1信号传导促进中枢记忆T细胞分化：这项研究证实，分离的CD 8 + T细胞表达mRNA，并在同源肽识别后产生TGF-β。用TGF-β阻断性Ab或TGF-β RI的小分子抑制剂阻断内源性TGF-β可增强CD 62 L高/CD 44高中枢记忆CD 8 + T细胞的产生，并伴有强烈的回忆应答。有趣的是，中央记忆T细胞池内的扩增代替细胞增殖或活化发生，但预期中胚层/T-bet转录因子的比率增加。然而，信号转导途径似乎是非经典的，独立于SMAD或哺乳动物雷帕霉素信号转导靶点。在人外周血单核细胞中也证实了TGF-β阻断可增强中枢记忆产生。这些发现强调了自分泌TGF-β在T细胞稳态中的作用，特别是效应/记忆和中枢/记忆T细胞的平衡。这些结果可能为靶向TGF-β信号传导以增强针对致死性感染或癌症的抗原特异性CD 8 + T细胞记忆提供理论基础。

Studies on the connection of innate and adaptive anti-cancer immunity include: The immunocytokine NHS-IL12 as a potential cancer therapeutic: A tumor-targeting interleuken (IL)-12 immunocytokine, NHS-IL12, was engineered by genetically fusing the human IL-12 heterodimers to the C-termini of the heavy chains of the NHS76 antibody. NHS76 is a fully human antibody selected for its specific ability to bind to DNA/histones and thereby target to tumors in vivo. A radiolabeled chimeric form of this antibody has been shown to selectively target human tumors and has been approved for the therapy of lung carcinoma in China. To visualize the subcellular localization of NHS-muIL12 in a murine model, we injected tumor-bearing mice subcutaneously (s.c.) with NHS-IL12 and distinct tumor targeting and staining in the nuclei of tumor cells was observed. This immunocytokine outperformed an equimolar dose of recombinant murine IL-12 (rMuIL-12) in anti-tumor studies of three distinct tumor models (LLC, MC38 and B16). NHS-muIL12 was found to increase serum IFN-gamma levels, upregulate MHC class I protein expression on DCs, and induce the proliferation of CD49b+ natural killer (NK) cells and CD8+ T cells, all in a dose-dependent manner. An immune cell subset depletion study confirmed that the antitumor effects of NHS-muIL12 involves CD8+ cells and NK cells, consistent with the known mechanisms of action of IL-12. Mice that were cured of their MC38 tumors showed resistance to tumor rechallenge and displayed long-lasting TAA-specific CTL memory. This enhanced efficacy observed of NHS-muIL12 vs. rMuIL-12 likely stems from the more favorable pharmacokinetic properties of the immunocytokine and its tumor-binding ability. NHS-IL12 has also been employed preclinically in combination with several standard-of-care therapies. We have shown statistically enhanced anti-tumor effects, compared to the use of either agent alone, when NHS-IL12 was used in combination with (a) fractionated radiation (Lewis lung carcinoma), (b) the TKI sunitinib (Renca renal carcinoma), and (c) docetaxel (MC38 colon cancer model). A Phase I study of NHS-IL12 is ongoing. The immune-potentiating effects on CD8+ T cells by a low dose of saracatinib might afford better protection from pathogens or cancer when combined with vaccine. Inhibition of TGF-beta1 signaling promotes central memory T-cell differentiation: This study affirmed that isolated CD8+ T cells express mRNA and produce TGF-beta following cognate peptide recognition. Blockage of endogenous TGF-beta with either a TGF-beta blocking Ab or a small molecule inhibitor of TGF-betaRI enhances the generation of CD62Lhigh/CD44high central memory CD8+ T cells accompanied with a robust recall response. Interestingly, the augmentation within the central memory T-cell pool occurs in lieu of cellular proliferation or activation, but with the expected increase in the ratio of the Eomesoderm/T-bet transcriptional factors. Yet, the signal transduction pathway(s) seems to be noncanonical, independent of SMAD or mammalian target of rapamycin signaling. Enhancement of central memory generation by TGF-beta blockade is also confirmed in human peripheral blood mononuclear cells. The findings underscore the role(s) that autocrine TGF-beta plays in T-cell homeostasis and, in particular, the balance of effector/memory and central/memory T cells. These results may provide a rationale to targeting TGF-beta signaling to enhance antigen-specific CD8+ T-cell memory against a lethal infection or cancer.