Umirolimus

体内模型小鼠NK细胞的发育、功能特性的调节、记忆样特征的获得与NK细胞受体等多个方面均呈现和人类的同源性。主要发展变迁：nu/nu裸鼠：1962年发现的自发突变nu/nu裸鼠缺乏胸腺，因此具有T细胞缺陷和B细胞功能受损，但保留了巨噬细胞和NK细胞功能水平。SCID小鼠：另一种包含常染色体隐性纯合子Prkdscd突变体导致严重的联合免疫缺陷(SCID)的小鼠模型为被称为SCID小鼠。相对nu/nu裸鼠，SCID小鼠还减少了NK细胞数量。部分SCID小鼠的表型是“leaky”的，幼鼠可以随机产生一些功能性B细胞和T细胞的克隆。NOG小鼠和NSG小鼠：NSG和NOG相似，截断了IL2受体伽马链细胞内信号域。NSG和NOG小鼠缺乏成熟的T、B细胞、NK细胞和补体，巨噬细胞和树突状细胞也有缺陷，例如普通人源化NSG小鼠中，人NK细胞的频率低于生理水平。NK细胞发育的减少可能是由于人类淋巴或NK细胞祖细胞与受体微环境之间的物种屏障。NOD-SCID小鼠：是通过将C.B-17 Prkdccid雄性与非肥胖型糖尿病(NOD)/ShiLtd Sz雌性杂交所产生的品系。NOD小鼠模型本身具有NK细胞亚群天然免疫缺陷的特点，将SCID突变转移到NOD背景中则能够消除SCID模型表型“泄露”的缺点。NOD-SCID小鼠缺乏T和B淋巴细胞，表现为NK细胞功能降低，异种移植植入率增加。NOD-SCID小鼠再分别与NOG小鼠或NSG小鼠回交后，IL-2受体共同伽马链被截断或缺失，从而能进一步提高人源细胞的植入率。局限性：小鼠寿命较短，一般为7-8个月，会频繁自发发展胸腺淋巴瘤；非人源化的患者来源的肿瘤异种移植(PDX)似乎受到不同移植肿瘤碎片中TIL成分的可能变异性的限制。人源化小鼠：在小鼠体内传代两代后，小鼠的间质可以取代人的间质，容易发生人肿瘤成分与小鼠肿瘤相关细胞之间的串扰。因此需要开发人源化小鼠模型。hu-BLT小鼠：由人源胎肝和胸腺组织在小鼠肾包膜中移植而建立。hu-BLT小鼠模型显示了人类免疫细胞库的完全重建，其T细胞能够装载HLA-II和HLA-I限制性的特异性反应。局限性：产生的NK细胞数量相对较少，功能较差。细胞因子：单纯人源化小鼠模型中，细胞因子在免疫低下的小鼠中可能表达水平极差。同时，鼠源细胞因子和人源细胞因子的差异也明显。因此出现了转基因表达人类细胞因子的小鼠模型。NOG-hIL-2 Tg小鼠：人脐血来源的HSCs可以成熟并分化为表达IL-2激活表型的KIR+NK细胞。NOG-hIL-15 Tg小鼠：高水平的IL-15可以支持从转移的人PBMC中获得的NK细胞的存活。hIL-7和hIL-15双敲入 NSG小鼠：hIL-56xhIL-94 KI NSG人源化小鼠模型中，BM CD94+CD16+细胞的百分比为42.6%，脾CD94+CD16+细胞为73.6%， PB CD94+CD16+ 细胞百分比为83.8%。普通NSG人源化小鼠的对应数据则为28.8%、27.2%和40.7%。Front. Immunol.体外模型对于实体瘤而言，3D培养物体外模型能比2D培养物更好地表现NK细胞介导的肿瘤监测和治疗反应。 3D培养物包括基于支架的培养物、无支架培养物和类器官。在肿瘤的背景下，“球状体”和“类器官”之间的界限变得不那么清晰，因此下文将其统称为用于将肿瘤组织概括为“肿瘤球体”的3D模型。Front. Immunol.肿瘤球体3D模型的培养方法包括：（1）旋转培养物：在旋转烧瓶中放置肿瘤细胞悬浮液，持续搅拌以促进细胞聚集。根据每种细胞类型的粘附性，球体在几天或几周内形成。植入小鼠前需将旋转培养产生的球体暴露在同种异体淋巴细胞培养中。优点：可以灵活控制球体的数量；简单易用，成本效益高。缺点：孵育时间和最佳搅拌速度均取决于细胞类型；同一批操作下产生的球体形状和大小不均匀；不能直接监测球体的形成过程。（2）液体覆盖法：将细胞悬浮液接种到标准培养板中，用琼脂糖或聚HEMA等非粘附性涂层进行预处理，通过防止细胞与培养板粘连来间接促进球体的形成，培养时间约为数天。NK细胞可与肿瘤球体共培养，研究其在体外的侵袭和杀伤能力。缺点：仅依赖于细胞自我聚集能力，球体形成成功率低，通常需要添加细胞外基质；常用塑料表面的U形和光学性质与高质量和高分辨率的成像不兼容，仍然需要样品转移。（3）悬滴培养法：将细胞悬浮液滴放到颠倒的标准培养板上。表面张力和重力迫使每一滴在几天内形成一个单一的球体。缺点：悬滴法并没有完全解决细胞系之间的异质结构完整性问题，相比液体覆盖法更容易出现松散聚集体的情况。（4）基于3D Biomatrix和InSphero平板和无支架长期高通量微柱-微孔夹心平台：通过将电池悬浮液转移到阵列板的入口处，从而形成多个液滴。液态库可防止液滴蒸发。在球体形成后，通过在入口顶部移液或通过离心法将每一滴移位到ULA板的单孔中。该悬挂液滴过程派生的椭球体和液体覆盖法效果相同。（5）基于支架的微流体平台：该微流控装置由充满I型胶原三维水凝胶的中央腔室、悬挂液滴衍生的球状体和NK细胞组成。腔室两边的腔体上涂有内皮细胞，以模仿血管。通过腔体，灌注含有IL-2缀合的CD16- EpCAM双特异性抗体溶液。球状体能够引发肿瘤细胞的缺氧反应。通过横向血管灌注抗体或直接嵌入水凝胶，可以用于研究抗体的动态及其对NK细胞ADCC能力的影响。 OncoImmunology缺点：基于支架的球体培养物是研究白细胞迁移和组织浸润的生物学相关系统，但它们通常与高通量筛选和活细胞成像不兼容。再加上从水凝胶中回收细胞的过程非常费力，限制其大规模应用。（6）小型化微流体平台MIVO：3D细胞载藻酸盐水凝胶衍生的球体被转移到MIVO设备的顶部腔室中。NK细胞悬浮液通过在含有球体的小室下运行的毛细血管进行灌流，允许NK细胞通过跨孔膜迁移并渗入肿瘤球体。优点：通过移液可以轻松回收细胞和培养基以进行细胞和蛋白质组分析；终点成像可以直接在芯片上进行。缺点：NK细胞粘附和浸润的动态不能完全通过实时成像来跟踪，并且球体培养不能直接在微芯片上进行。（7）超声驻波(USW)诱导的微孔芯片：将细胞接种到覆盖有非粘性涂层的硅微孔阵列芯片中，并通过USW诱导细胞聚集来获得球状体的形成。超短波照射导致每个微孔中心形成单一椭球体。当USW关闭时，细胞ECM蛋白的产生和紧密的细胞间连接的形成继续，从而实现长期的球体培养。一旦球体形成，NK细胞就可以被接种到超短波照射下的孔中，以促进NK细胞与球体的相互作用。NK细胞在肿瘤球体中的浸润和杀伤的特征可以通过成像直接在芯片内进行，也可以在芯片外通过从肿瘤球体中提取样本来进行。优点：该芯片与高分辨率活细胞成像兼容；长时间的USW连续暴露对细胞的作用较为温和；能够诱导细胞聚集并在每个孔中形成单一、均匀和致密的球体；较小型，材料需求低。缺点：可以并行测试的条件数量少；可以从芯片中检索以进行进一步分析的细胞数量较低。参考文献：Carannante V, Wiklund M and Önfelt B (2023) In vitro models to study natural killer cell dynamics in the tumor microenvironment. Front. Immunol. 14:1135148. doi: 10.3389/fimmu.2023.1135148Parodi M, Astigiano S,et al. (2023) Murine models to study human NK cells in human solid tumors. Front. Immunol. 14:1209237. doi: 10.3389/fimmu.2023.1209237Masashi Matsuda,et al.Human NK cell development in hIL-7 and hIL-15 knockin NOD/SCID/IL2rgKO mice. Life Science Alliance Apr 2019, 2 (2) e201800195; DOI: 10.26508/lsa.201800195Jose M. Ayuso, Regan Truttschel ,et al.(2019) Evaluating natural killer cell cytotoxicity against solid tumors using a microfluidic model, OncoImmunology, 8:3, DOI: 10.1080/2162402X.2018.1553477

SINGAPORE, Feb. 9, 2015 /PRNewswire/ -- Biosensors International has announced completion of patient enrollment in LEADERS Free Japan, a revolutionary trial involving BioFreedom, the company's novel polymer and carrier-free drug-coated stent (DCS).   LEADERS Free is the world's first prospective, randomised double-blind clinical trial employing only a one-month course of dual anti-platelet therapy (DAPT) after implantation of an active stent. The trial is focused on patients at high risk of bleeding, and has been designed to confirm that BioFreedom is as safe as a bare-metal stent (BMS) in this patient group, while delivering the anti-restenotic benefit of a drug-eluting stent (DES).  LEADERS Free Japan, a prospective, multi-centre open-label trial, is applying the same patient selection criteria and duration of DAPT as LEADERS Free, but with simply a BioFreedom treatment arm.   The objective of LEADERS Free Japan is to confirm that the safety and efficacy of BioFreedom in Japanese patients is equivalent to that observed in patients of other ethnicities, as assessed in the active (BioFreedom) arm of LEADERS Free. Safety is being measured by the composite of cardiac death, myocardial infarction and definite/probable stent thrombosis at one year, and efficacy by the incidence of clinically driven target lesion revascularization at one year. LEADERS Free Japan has enrolled 140 patients identified as having a high risk of bleeding, from 12 centres across the country. All patients are being prescribed only one month of DAPT.  "I am delighted to have completed patient enrollment in this groundbreaking study," commented Principal Investigator Dr. Shigeru Saito, Shonan Kamakura General Hospital, Kanagawa, Japan. "It is a unique clinical trial, not only for the stent itself but for the unprecedented trial design and the challenging patient population. We expect to gain valuable scientific and clinical findings from the trial, potentially showing the BioFreedom technology offers unique clinical benefits for our patients." "We hope that the results from LEADERS Free Japan will show, for the first time, that a drug-coated stent can be used safely and effectively with only one month of DAPT in Japanese patients at high risk of bleeding," added Dr Philip Urban, Principal Investigator for LEADERS Free. LEADERS Free has enrolled 2466 patients identified as having a high risk of bleeding from 68 sites across Europe, Asia, Australia and Canada.  Patients in both arms of the trial are being prescribed only one month of DAPT.  Primary endpoint data is expected later this year, and follow up is planned out to two years.   BioFreedom represents the latest development in Biosensors' stent technology, featuring an abluminal coating of Biolimus A9 (BA9) without the use of a polymer or other carrier. BA9 is a highly lipophilic anti-restenotic drug developed by Biosensors specifically for use with stents. LEADERS Free Japan will be the first clinical trial ever conducted by Biosensors of a BA9-coated stent in Japan. In its First in Man ("FIM") study, treatment with BioFreedom demonstrated excellent 12-month late lumen loss and sustained safety up to five years, including absence of definite and/or probable stent thrombosis. BioFreedom has received CE Mark approval and is currently available in select markets. Biosensors has also received conditional IDE approval to conduct a US-based clinical trial of BioFreedom, designed to collect additional safety and effectiveness data. Media/Investor Relations Contact Tel: (65) 6213 5777 Email: ir@biosensors.com About Biosensors International Group, Ltd Biosensors International develops, manufactures and markets innovative medical devices for interventional cardiology and critical care procedures. With the BioMatrix family of drug-eluting stents and the Axxess self-expanding bifurcation stent, we are a leader in the global coronary stent market. These stents incorporate Biolimus A9 (BA9), an anti-restenotic drug developed specifically for use with stents and patented by Biosensors, together with a unique abluminal biodegradable polymer coating, which fully degrades into carbon dioxide and water after six to nine months as it releases BA9. The BioMatrix family features workhorse stent platforms for a broad range of lesions, and Axxess employs a self-expanding stent platform specifically designed for treating bifurcation lesions. The BioFreedom drug-coated stent, which has received CE Mark approval, underscores our technology leadership in the field of coronary stents.  BioFreedom is the world's first polymer and carrier -free stent with BA9. Chroma, a cobalt chromium bare-metal stent featuring an innovative platform design, offers exceptional deliverability without any compromise on radial strength or recoil. Our drug-eluting balloon range complements the stent portfolio and offers interventional cardiologists a broader range of treatment options.    For more information, please visit To view the original version on PR Newswire, visit: SOURCE Biosensors International Group, Ltd. Help employers find you! Check out all the jobs and post your resume.