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肿瘤免疫治疗是继手术、放疗和化疗后出现的一种新的治疗方法,能够克服放化疗杀伤正常细胞的缺点。免疫细胞在肿瘤的免疫治疗中居于核心地位,细胞的成熟状态、引入途径、迁移和归巢能力都将影响免疫治疗的效果,阐明免疫细胞在体内的迁移途径及迁移特性有助于人们更深入地理解免疫系统与肿瘤的作用机制。因此,我们需要一种无创的、可重复的并且能够实时监测体内细胞活动的成像方法。在体运用成像技术示踪免疫细胞虽然困难重重,但近些年来仍然取得了一定的进展。
分子和细胞影像技术将生物技术和成像方法有机地结合起来,监测生理和病理状态下体内分子和细胞的变化情况。该技术是对活体内分子和细胞以及体内生物学变化和细胞过程进行的一种无创的、可重复的成像技术[1],主要涉及以下两个方面[2]:一是对比剂、示踪剂和报告探针相关技术,二是成像技术。目前,研究较为广泛的分子和细胞影像技术主要有PET、SPECT、荧光显像和MRI。PET和SPECT具有较高的灵敏度,但空间分辨率差。荧光成像是细胞水平研究的重要工具,灵敏度高、价格便宜、操作简单,但是其空间分辨率差,活体成像效果受组织穿透深度的限制,目前仍无商用的基于荧光成像的临床诊断仪器。MRI克服了荧光显像、PET与SPECT的缺点,具有优异的空间分辨率,显像不受组织深度的限制。随着高场强MRI和新型对比剂的出现,MRI灵敏度不佳的缺点也随之克服。利用MRI监测体内标记细胞的迁移途径不仅作为一种研究方法,而且作为一种潜在的临床诊断工具,受到越来越广泛的关注。
目前,研究最多的细胞MRI对比剂是超顺磁性对比剂,主要包括超顺磁性氧化铁纳米颗粒(superparamagnetic iron oxide nanoparticles,SPION)[3]、超小超顺磁性氧化铁纳米颗粒(ultrasmall superparamagnetic iron oxide nano-particles,USPION)[4]和微小氧化铁颗粒(micron-sized iron oxide particles,MPIO)[5]等。另外,还有单晶氧化铁颗粒(monocrystalline iron oxide particles,MION)[4]和交叉结合氧化铁(cross-linked iron oxides,CLIO)[4]等。不同对比剂MRI信号特征各不相同,如氧化铁纳米颗粒在T2加权呈低信号,钆离子螯合物T1加权上呈高信号,从而根据不同的信号特征监测免疫细胞的生物学分布以及它们在靶器官的定位。
细胞标记技术可以分为两大类:直接标记和间接标记。直接标记是示踪某种特定细胞最常用的方法。在直接标记中,免疫细胞直接内化标记物。免疫细胞在体外用标记探针,如荧光物质、放射性示踪剂或顺磁性纳米颗粒进行标记后回输体内,分别用荧光显像、PET/SPECT或MRI进行体内示踪。直接标记的优势在于操作简单,标记探针能够与特异的靶细胞结合或者能够容易地穿透细胞膜。直接标记的缺陷: ①标记水平取决于细胞的标记物摄取能力。②只能用来在体示踪终末分化细胞,如树突状细胞(dendritic cells,DCs)和巨噬细胞,而不能长时间监测体内细胞的活性和增殖能力。③可能会影响细胞的迁移、活性、功能、增殖以及分化能力。利用转染介质(transfection agents)(如多聚L-赖氨酸、鱼精蛋白硫酸盐等)[6]、电穿孔技术(electroporation)[7]、HIV-1反式作用因子肽(HIV-1 transactivator peptides,HIV-1-TAT)[8]修饰颗粒表面可以更有效地进行细胞标记。另外,细胞标记效率还与细胞类型有关,如吞噬细胞容易内化纳米颗粒,而非吞噬细胞则需要多聚L-赖氨酸或鱼精蛋白硫酸盐等带正电载体辅助纳米颗粒的内化。间接标记需要进行基因修饰,表达可被探测到的报告蛋白或产生酶促反应,目前应用较少。本文重点介绍直接标记法细胞MRI在体示踪DCs、T淋巴细胞、巨噬细胞和自然杀伤(natural killer,NK)细胞。
细胞磁共振成像技术在体示踪免疫细胞的研究进展
Advances in tracking immunocytes using cellular magnetic resonance imaging in vivo
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摘要: 肿瘤免疫治疗是继手术、放疗和化疗后出现的一种新的治疗方法。在体示踪免疫细胞有助于指导肿瘤的免疫治疗并预测和评估其治疗效果。细胞磁共振成像技术运用特殊的对比剂,能够无创、实时、可重复地监测体内细胞的活动。近年来,研究者对应用细胞磁共振成像技术在体示踪免疫细胞进行了大量的研究并取得了一定的进展,该文将就这一研究进展作一综述。Abstract: Tumor immunotherapy is a new treatment modality following surgical resection, chemotherapy and radiotherapy.In vivo tracking immunocyte helps to direct immunotherapy, as well as predict and assess the treatment effect.Cellular magnetic resonance imaging, applying specific contrast agents, is a non-invasive imaging modality capable of monitoring the real-time migration of cells in vivo repeatedly.These years, a lot of related studies have been conducted and certain research progress has been achieved.This article reviews the advances in the study of immunocytes tracking using cellular magnetic resonance image in vivo.
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Key words:
- Magnetic resonance imaging /
- Immunocytes /
- Tracking /
- Contrast agents /
- In vivo
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[1] Bulte JW, Kraitchman DL.Iron oxide MR contrast agents for molecular and cellular imaging[J].NMR Biomed, 2004, 17(7): 484-499. [2] Luciqnani G, Ottobrini L, Martelli C, et al.Molecular imaging of cell-mediated cancer immunotherapy[J].Trends Biotechnol, 2006, 24(9): 410-418. [3] Li L, Jiang W, Luo K, et al.Superparamagnetic iron oxide nanoparticles as MRI contrast agents for non-invasive stem cell labeling and tracking[J].Theranostics, 2013, 3(8): 595-615. [4] Li M, Kim HS, Tian L, et al.Comparison of two ultrasmall superparamagnetic iron oxides on cytotoxicity and MR imaging of tumors[J].Theranostics, 2012, 2(1): 76-85. [5] Valable S, Barbier EL, Bernaudin M, et al.In vivo MRI tracking of exogenous monocytes/macrophages targeting brain tumors in a rat model of glioma[J].Neuroimage, 2008, 40(2): 973-983. [6] Arbab AS, Yocum GT, Kalish H, et al.Efficient magnetic cell labeling with protamine sulfate complexed to ferumoxides for cellular MRI[J].Blood, 2004, 104(4): 1217-1223. [7] Wang L, Wang Z, Frank TG, et al.Rapid and efficient cell labeling with a MRI contrast agent by electroporation in the presence of protamine sulfate[J].Nanomedicine(Lond), 2009, 4(3): 305-315. [8] Lewin M, Carlesso N, Tung CH, et al.Tat peptide-derivatized magnetic nanoparticles allow in vivo tracking and recovery of progenitor cells[J].Nat Biotechnol, 2000, 18(4): 410-414. [9] Langenkamp A, Messi M, Lanzavecchia A, et al.Kinetics of dendritic cell activation: impact on priming of TH1, TH2 and nonpolarized T cells[J].Nat Immunol, 2000, 1(4): 311-316. [10] Figdor CG, de Vries IJ, Leaterhuis WJ, et al.Dendritic cell immunotherapy: mapping the way[J].Nat Med, 2004, 10(5): 475-480. [11] de Vries IJ, Leaterhuis WJ, Barentsz JO, et al.Magnetic resonance tracking of dendritic cells in melanoma patients for monitoring of cellular therapy[J].Nat Biotechnol, 2005, 23(11): 1407-1413. [12] Aspord C, Laurin D, Janier MF, et al.Paramagnetic nanoparticles to track and quantify in vivo immune human therapeutic cells[J].Nanoscale, 2013, 5(23): 11409-11415. [13] Rohani R, de Chickera SN, Willert C, et al.In vivo cellular MRI of dendritic cell migration using micrometer-sized iron oxide(MPIO)particles[J].Mol Imaging Biol, 2011, 13(4): 679-694. [14] Liu L, Ye Q, Wu Y, et al.Tracking T-cells in vivo with a new nano-sized MRI contrast agent[J].Nanomedicine, 2012, 8(8): 1345-1354. [15] Shapiro EM, Medford-Davis LN, Fahmy TM, et al.Antibody-mediated cell labeling of peripheral T cells with micron-sized iron oxide particles (MPIOs)allows single cell detection by MRI[J].Contrast Media Mol Imaging, 2007, 2(3): 147-153. [16] Petry KG, Boiziau C, Dousset V, et al.Magnetic resonance imaging of human brain macrophage infiltration[J].Neurotherapeutics, 2007, 4(3): 434-442. [17] Figueiredo S, Cutrin JC, Rizzitelli S, et al.MRI tracking of macrophages labeled with glucan particles entrapping a water insoluble paramagnetic Gd-based agent[J].Mol Imaging Biol, 2013, 15(3): 307-315. [18] Jinushi M, Takehara T, Tatsumi T, et al.Negative regulation of NK cell activities by inhibitory receptor CD94/NKG2A leads to the altered NK cell-induced modulation of dendritic cell functions in chronic hepatitis C virus infection[J].J Immunol, 2004, 173(10): 6072-6081. [19] Farag SS, Caliqiuri MA.Human natural killer cell development and biology[J].Blood Rev, 2006, 20(3): 123-137. [20] Albertsson PA, Basse PH, Hokland M, et al.NK cells and the tumour microenvironment: implications for NK-cell function and anti-tumour activity[J].Trends Immunol, 2003, 24(11): 603-609. [21] Mallett CL, McFadden C, Chen Y, et al.Migration of iron-labeled KHYG-1 natural killer cells to subcutaneous tumors in nude mice, as detected by magnetic resonance imaging[J].Cytotherapy, 2012, 14(6): 743-751. [22] Meier R, Golovko D, Tavri S, et al.Depicting adoptive immunotherapy for prostate cancer in an animal model with magnetic resonance imaging[J].Magn Reson Med, 2011, 65(3): 756-763.
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