■NK细胞可以通过自然细胞毒性和抗体依赖性细胞介导的细胞毒性(ADCC)介导肿瘤细胞杀伤,通过IgGFc受体CD16A(FcγRIIIA)介导的抗肿瘤机制。CD16A多态性赋予IgG亲和力增加,与淋巴瘤单克隆抗体治疗期间的临床结果呈正相关,通过ADCC连接增加的结合亲和力和增加的治疗潜力。我们以前曾报道过FcγR融合CD64/16A由CD64(FcγRI)的胞外区组成,一种通常由髓样细胞表达的高亲和力Fc受体,和CD16A的跨膜/细胞质区域,创造一种高效的新型活化融合受体。这里,我们评估了表达CD64/16A的工程诱导多能干细胞(iPSC)衍生的NK(iNK)细胞的治疗潜力,具有多抗原靶向潜力的抗体武装细胞治疗产品。
iNK细胞由被工程化以表达CD64/16A和用于细胞因子独立性的白介素(IL)-15/IL-15Rα融合(IL-15RF)蛋白的iPSC产生。使用辐照的K562-mbIL21-41BBL饲养细胞扩增iNK细胞和外周血NK细胞,以使用Raji淋巴瘤细胞系进行体外和体内测定。通过IncuCyte测定并使用具有高循环水平的人IgG的异种移植小鼠模型实时评估ADCC。
■我们的数据表明表达CD64/16A的iNK细胞可以介导针对人B细胞淋巴瘤的有效抗肿瘤活性。特别是,(I)在次优条件下,包括低抗体浓度和低效应物与靶标之比,iNK-CD64/16A细胞介导ADCC,(ii)iNK-CD64/16A细胞可以预先加载肿瘤靶向抗体(武装)以引发ADCC,(iii)武装的iNK-CD64/16A细胞可以用额外的抗体重新利用以靶向新的肿瘤抗原,和(iv)冷冻保存,武装的iNK-CD64/16A能够在饱和水平的人IgG下在肿瘤异种移植模型中持续ADCC。
■iNK-CD64/16A细胞允许灵活使用抗体(抗体武装和抗体靶向),和“现成的”多抗原识别平台,以克服表达固定抗原受体的过继细胞疗法的局限性,导致由于抗原逃逸变体而导致癌症复发。
UNASSIGNED: NK cells can mediate tumor cell killing by natural cytotoxicity and by antibody-dependent cell-mediated cytotoxicity (ADCC), an anti-tumor mechanism mediated through the IgG Fc receptor CD16A (FcγRIIIA). CD16A polymorphisms conferring increased affinity for IgG positively correlate with clinical outcomes during monoclonal antibody therapy for lymphoma, linking increased binding affinity with increased therapeutic potential via ADCC. We have previously reported on the FcγR fusion CD64/16A consisting of the extracellular region of CD64 (FcγRI), a high-affinity Fc receptor normally expressed by myeloid cells, and the transmembrane/cytoplasmic regions of CD16A, to create a highly potent and novel activating fusion receptor. Here, we evaluate the therapeutic potential of engineered induced pluripotent stem cell (iPSC)-derived NK (iNK) cells expressing CD64/16A as an \"off-the-shelf\", antibody-armed cellular therapy product with multi-antigen targeting potential.
UNASSIGNED: iNK cells were generated from iPSCs engineered to express CD64/16A and an interleukin (IL)-15/IL-15Rα fusion (IL-15RF) protein for cytokine independence. iNK cells and peripheral blood NK cells were expanded using irradiated K562-mbIL21-41BBL feeder cells to examine in in vitro and in vivo assays using the Raji lymphoma cell line. ADCC was evaluated in real-time by IncuCyte assays and using a xenograft mouse model with high circulating levels of human IgG.
UNASSIGNED: Our data show that CD64/16A expressing iNK cells can mediate potent anti-tumor activity against human B cell lymphoma. In particular, (i) under suboptimal conditions, including low antibody concentrations and low effector-to-target ratios, iNK-CD64/16A cells mediate ADCC, (ii) iNK-CD64/16A cells can be pre-loaded with tumor-targeting antibodies (arming) to elicit ADCC, (iii) armed iNK-CD64/16A cells can be repurposed with additional antibodies to target new tumor antigens, and (iv) cryopreserved, armed iNK-CD64/16A are capable of sustained ADCC in a tumor xenograft model under saturating levels of human IgG.
UNASSIGNED: iNK-CD64/16A cells allow for a flexible use of antibodies (antibody arming and antibody targeting), and an \"off-the-shelf\" platform for multi-antigen recognition to overcome limitations of adoptive cell therapies expressing fixed antigen receptors leading to cancer relapse due to antigen escape variants.