Convergence Medicine Research Center, Asan Medical Center, Seoul, Republic of Korea.
College of Veterinary Medicine, Chonnam National University, Gwangju, Republic of Korea.
Front Immunol. 2024 Jul 26;15:1365946. doi: 10.3389/fimmu.2024.1365946. eCollection 2024.
Humanized mouse models to recapitulate human biological systems still have limitations, such as the onset of lethal graft-versus-host disease (GvHD), a variable success rate, and the low accessibility of total body irradiation (TBI). Recently, mice modified with the CD47-SIRPA axis have been studied to improve humanized mouse models. However, such trials have been rarely applied in NOD mice. In this study, we created a novel mouse strain, NOD-CD47Rag2IL-2rγ (RTKO) mice, and applied it to generate humanized mice.
Four-week-old female NOD-Rag2IL-2rγ (RID) and RTKO mice pre-conditioned with TBI or busulfan (BSF) injection were used for generating human CD34+ hematopoietic stem cell (HSC) engrafted humanized mice. Clinical signs were observed twice a week, and body weight was measured once a week. Flow cytometry for human leukocyte antigens was performed at intervals of four weeks or two weeks, and mice were sacrificed at 48 weeks after HSC injection.
For a long period from 16 to 40 weeks post transplantation, the percentage of hCD45 was mostly maintained above 25% in all groups, and it was sustained the longest and highest in the RTKO BSF group. Reconstruction of human leukocytes, including hCD3, was also most prominent in the RTKO BSF group. Only two mice died before 40 weeks post transplantation in all groups, and there were no life-threatening GvHD lesions except in the dead mice. The occurrence of GvHD has been identified as mainly due to human T cells infiltrating tissues and their related cytokines.
Humanized mouse models under all conditions applied in this study are considered suitable models for long-term experiments based on the improvement of human leukocytes reconstruction and the stable animal health. Especially, RTKO mice pretreated with BSF are expected to be a valuable platform not only for generating humanized mice but also for various immune research fields.
recapitulate 重现；humanized mouse models 人源化小鼠模型；limitations 局限性；lethal graft-versus-host disease (GvHD) 致命的移植物抗宿主病；a variable success rate 成功率不稳定；total body irradiation (TBI) 全身照射。人源化小鼠模型仍然存在一些局限性，如致命的移植物抗宿主病（GvHD）的发作、成功率不稳定和全身照射（TBI）的低可及性。最近，研究人员利用 CD47-SIRPA 轴对小鼠进行了修饰，以改进人源化小鼠模型。然而，这种试验在 NOD 小鼠中很少应用。在这项研究中，我们创建了一种新型小鼠品系，即 NOD-CD47Rag2IL-2rγ（RTKO）小鼠，并将其应用于生成人源化小鼠。
使用 4 周龄雌性 NOD-Rag2IL-2rγ（RID）和 RTKO 小鼠，经 TBI 或白消安（BSF）预处理，生成人 CD34+造血干细胞（HSC）移植的人源化小鼠。每周观察两次临床症状，每周测量一次体重。每四周或两周进行一次人白细胞抗原流式细胞术检测，HSC 注射后 48 周处死小鼠。
在移植后 16 至 40 周的很长一段时间内，所有组的 hCD45 百分比大多维持在 25%以上，RTKO BSF 组的维持时间最长、比例最高。RTKO BSF 组的人白细胞重建，包括 hCD3，也最为显著。所有组中只有两只小鼠在移植后 40 周前死亡，除死亡小鼠外，没有危及生命的 GvHD 病变。GvHD 的发生主要归因于人类 T 细胞浸润组织及其相关细胞因子。
根据人白细胞重建的改善和动物健康的稳定，本研究应用的所有条件下人源化小鼠模型被认为是适合长期实验的模型。特别是，用 BSF 预处理的 RTKO 小鼠不仅有望成为生成人源化小鼠的有价值平台，而且有望成为各种免疫研究领域的有价值平台。
