细胞因子工程的进展正在克服这些蛋白质作为药物的局限性，从而推动治疗转化。白细胞介素 2 (IL-2) 细胞因子是一种有前途的癌症治疗免疫刺激剂，但由于其同时激活促炎免疫效应细胞和抗炎调节 T 细胞、高剂量时的毒性以及血清半衰期短而受到限制。 -生活。提高 IL-2 选择性、安全性和寿命的一种方法是与抗 IL-2 抗体复合，使细胞因子偏向免疫效应细胞激活。尽管该策略在临床前模型中显示出潜力，但由于配制多蛋白药物的挑战以及对复合物稳定性的担忧，细胞因子/抗体复合物的临床转化变得复杂。在这里，我们介绍了一种设计分子内组装的单剂融合蛋白​​（免疫细胞因子，IC）的通用方法，该融合蛋白包含 IL-2 和偏向性抗 IL-2 抗体，该抗体将细胞因子导向免疫效应细胞。我们优化了 IC 结构并设计了细胞因子/抗体亲和力以改善免疫偏差。我们证明，我们的 IC 优先激活和扩增免疫效应细胞，与天然 IL-2 相比，无论是单独使用还是与免疫检查点抑制剂联合使用，都具有优异的抗肿瘤活性。此外，观察到治疗效果而不诱发毒性。这项工作提出了细胞因子/抗体融合蛋白的设计和翻译的路线图。

Progress in cytokine engineering is driving therapeutic translation by overcoming these proteins' limitations as drugs. The interleukin-2 (IL-2) cytokine is a promising immune stimulant for cancer treatment but is limited by its concurrent activation of both pro-inflammatory immune effector cells and anti-inflammatory regulatory T cells, toxicity at high doses, and short serum half-life. One approach to improve the selectivity, safety, and longevity of IL-2 is complexation with anti-IL-2 antibodies that bias the cytokine towards immune effector cell activation. Although this strategy shows potential in preclinical models, clinical translation of a cytokine/antibody complex is complicated by challenges in formulating a multi-protein drug and concerns regarding complex stability. Here, we introduced a versatile approach to designing intramolecularly assembled single-agent fusion proteins (immunocytokines, ICs) comprising IL-2 and a biasing anti-IL-2 antibody that directs the cytokine towards immune effector cells. We optimized IC construction and engineered the cytokine/antibody affinity to improve immune bias. We demonstrated that our IC preferentially activates and expands immune effector cells, leading to superior antitumor activity compared to natural IL-2, both alone and combined with immune checkpoint inhibitors. Moreover, therapeutic efficacy was observed without inducing toxicity. This work presents a roadmap for the design and translation of cytokine/antibody fusion proteins.