背景:白细胞介素-15(IL-15)是发育过程中的关键细胞因子,扩散,和自然杀伤(NK)细胞的功能,NKT细胞,和CD8+记忆T细胞,并已成为治疗癌症和病毒性疾病最有前途的蛋白质分子之一。然而,在治疗中应用IL-15有几个局限性,例如其体外产量低,有限的效力,体内半衰期短。迄今为止,在癌症治疗中,有几种基于构型修饰的重组IL-15激动剂,例如ALT-803,其主要由哺乳动物细胞产生。
结果:在这项研究中,我们设计了两种不同形式的IL-15复合物,通过IL-15与IL-15受体α(SuIL-15Rα)-IgG4Fc融合蛋白的二聚体或单体寿司结构域的非共价组装形成,并命名为IL-15/SuIL-15Rα-dFc和IL-15/SuIL-15Rα-mFc,分别。两种IL-15复合物在巴斯德毕赤酵母中表达(P.pastoris),并对其活性和半衰期进行了评估和比较。药代动力学分析显示,IL-15/SuIL-15Rα-dFc的半衰期为14.26h,IL-15/SuIL-15Rα-mFc的半衰期为9.16h,其比商业重组人IL-15(rhIL-15)的0.7小时半衰期长得多。静脉注射两种IL-15复合物的小鼠治疗导致NK细胞显著增加,NKT细胞,和记忆CD8+T细胞,rhIL-15治疗后未观察到。用两种IL-15复合物处理来自健康供体的人外周血单核细胞(PBMC)产生增强的NK和CD8+T细胞活化和增殖,这与rhIL-15的效果相当。
结论:这些发现表明,在巴斯德毕赤酵母中产生的IL-15/SuIL-15Rα-dFc和IL-15/SuIL-15Rα-mFc表现出有效的活性和延长的半衰期,并可能在进一步的研究和应用中作为免疫疗法的超级激动剂。
BACKGROUND: Interleukin-15 (IL-15) is a critical cytokine for the development, proliferation, and function of natural killer (NK) cells, NKT cells, and CD8+ memory T cells and has become one of the most promising protein molecules for the treatment of cancer and viral diseases. However, there are several limitations in applying IL-15 in therapy, such as its low yield in vitro, limited potency, and short half-life in vivo. To date, there are several recombinant IL-15 agonists based on configurational modifications that are being pursued in the treatment of cancer, such as ALT-803, which are mainly produced from mammalian cells.
RESULTS: In this study, we designed two different forms of the IL-15 complex, which were formed by the noncovalent assembly of IL-15 with dimeric or monomeric sushi domain of IL-15 receptor α (SuIL-15Rα)-IgG4 Fc fusion protein and designated IL-15/SuIL-15Rα-dFc and IL-15/SuIL-15Rα-mFc, respectively. The two IL-15 complexes were expressed in Pichia pastoris (P. pastoris), and their activities and half-lives were evaluated and compared. Pharmacokinetic analysis showed that IL-15/SuIL-15Rα-dFc had a half-life of 14.26 h while IL-15/SuIL-15Rα-mFc had a half-life of 9.16 h in mice, which were much longer than the 0.7-h half-life of commercial recombinant human IL-15 (rhIL-15). Treatment of mice with intravenous injection of the two IL-15 complexes resulted in significant increases in NK cells, NKT cells, and memory CD8+ T cells, which were not observed after rhIL-15 treatment. Treatment of human peripheral blood mononuclear cells (PBMCs) from healthy donors with the two IL-15 complexes yielded enhanced NK and CD8+ T cell activation and proliferation, which was comparable to the effect of rhIL-15.
CONCLUSIONS: These findings indicate that the IL-15/SuIL-15Rα-dFc and IL-15/SuIL-15Rα-mFc produced in P. pastoris exhibit potent activities and prolonged half-lives and may serve as superagonists for immunotherapy in further research and applications.