DataSheet_1_Myeloid and dendritic cells enhance therapeutics-induced cytokine release syndrome features in humanized BRGSF-HIS preclinical model.docx

ObjectivesDespite their efficacy, some immunotherapies have been shown to induce immune-related adverse events, including the potentially life-threatening cytokine release syndrome (CRS), calling for reliable and translational preclinical models to predict potential safety issues and investigate their rescue. Here, we tested the reliability of humanized BRGSF mice for the assessment of therapeutics-induced CRS features in preclinical settings.
MethodsBRGSF mice reconstituted with human umbilical cord blood CD34+ cells (BRGSF-CBC) were injected with anti-CD3 antibody (OKT3), anti-CD3/CD19 bispecific T-cell engager Blinatumomab, or VISTA-targeting antibody. Human myeloid and dendritic cells’ contribution was investigated in hFlt3L-boosted BRGSF-CBC mice. OKT3 treatment was also tested in human PBMC-reconstituted BRGSF mice (BRGSF-PBMC). Cytokine release, immune cell distribution, and clinical signs were followed.
ResultsOKT3 injection in BRGSF-CBC mice induced hallmark features of CRS, specifically inflammatory cytokines release, modifications of immune cell distribution and activation, body weight loss, and temperature drop. hFlt3L-boosted BRGSF-CBC mice displayed enhanced CRS features, revealing a significant role of myeloid and dendritic cells in this process. Clinical CRS-managing treatment Infliximab efficiently attenuated OKT3-induced toxicity. Comparison of OKT3 treatment’s effect on BRGSF-CBC and BRGSF-PBMC mice showed broadened CRS features in BRGSF-CBC mice. CRS-associated features were also observed in hFlt3L-boosted BRGSF-CBC mice upon treatment with other T-cell or myeloid-targeting compounds.
ConclusionsThese data show that BRGSF-CBC mice represent a relevant model for the preclinical assessment of CRS and CRS-managing therapies. They also confirm a significant role of myeloid and dendritic cells in CRS development and exhibit the versatility of this model for therapeutics-induced safety assessment.

研究目标：尽管部分免疫疗法已展现出显著疗效，但现有研究表明其可诱发免疫相关不良反应，其中包括潜在致命性的细胞因子释放综合征（cytokine release syndrome, CRS），因此亟需可靠且可转化的临床前模型，以预测潜在安全性风险并探究其救治方案。本研究旨在验证人源化BRGSF小鼠（humanized BRGSF mice）用于临床前评估治疗诱导的CRS特征的可靠性。
研究方法：将接种人脐带血CD34+细胞（human umbilical cord blood CD34+ cells）的BRGSF小鼠（记为BRGSF-CBC小鼠）分别注射抗CD3抗体（OKT3，anti-CD3 antibody）、抗CD3/CD19双特异性T细胞衔接蛋白（bispecific T-cell engager）博纳吐单抗（Blinatumomab）以及靶向VISTA的单克隆抗体。此外，本研究在经人Flt3配体（hFlt3L）强化的BRGSF-CBC小鼠中，探究了人源髓系细胞与树突状细胞的作用；同时在接种人外周血单个核细胞（peripheral blood mononuclear cell, PBMC）的BRGSF小鼠（记为BRGSF-PBMC小鼠）中测试了OKT3的治疗效果。研究人员对细胞因子释放情况、免疫细胞分布以及临床体征进行了动态监测。
研究结果：在BRGSF-CBC小鼠中注射OKT3可诱导CRS的标志性特征，具体包括炎性细胞因子释放、免疫细胞分布与活化状态改变、体重下降以及体温降低。经hFlt3L强化的BRGSF-CBC小鼠则展现出更为显著的CRS特征，揭示了髓系细胞与树突状细胞在此过程中的关键调控作用。临床常用CRS管理药物英夫利昔单抗（Infliximab）可有效减轻OKT3诱导的毒性反应。对比OKT3对BRGSF-CBC与BRGSF-PBMC小鼠的作用效果发现，BRGSF-CBC小鼠的CRS特征更为广泛。此外，在经hFlt3L强化的BRGSF-CBC小鼠中，给予其他靶向T细胞或髓系细胞的化合物后，同样观察到了CRS相关特征。
研究结论：本研究结果表明，BRGSF-CBC小鼠可作为可靠的临床前模型，用于评估治疗诱导的CRS及CRS管理疗法。同时，本研究证实了髓系细胞与树突状细胞在CRS发生发展中的重要作用，并展示了该模型在治疗诱导的安全性评估中的通用性。