人肺树突状细胞：空间分布与表型鉴定支气管活检采用免疫组化和流式细胞仪
Summary
Lung-resident immune cells, including dendritic cells (DCs) in humans, are critical for defense against inhaled pathogens and allergens. However, due to the scarcity of human lung tissue, studies are limited. This work presents protocols to process human mucosal endobronchial biopsies for studying lung DCs using immunohistochemistry and flow cytometry.
Abstract
The lungs are constantly exposed to the external environment, which in addition to harmless particles, also contains pathogens, allergens, and toxins. In order to maintain tolerance or to induce an immune response, the immune system must appropriately handle inhaled antigens. Lung dendritic cells (DCs) are essential in maintaining a delicate balance to initiate immunity when required without causing collateral damage to the lungs due to an exaggerated inflammatory response. While there is a detailed understanding of the phenotype and function of immune cells such as DCs in human blood, the knowledge of these cells in less accessible tissues, such as the lungs, is much more limited, since studies of human lung tissue samples, especially from healthy individuals, are scarce. This work presents a strategy to generate detailed spatial and phenotypic characterization of lung tissue resident DCs in healthy humans that undergo a bronchoscopy for the sampling of endobronchial biopsies. Several small biopsies can be collected from each individual and can be subsequently embedded for ultrafine sectioning or enzymatically digested for advanced flow cytometric analysis. The outlined protocols have been optimized to yield maximum information from small tissue samples that, under steady-state conditions, contain only a low frequency of DCs. While the present work focuses on DCs, the methods described can directly be expanded to include other (immune) cells of interest found in mucosal lung tissue. Furthermore, the protocols are also directly applicable to samples obtained from patients suffering from pulmonary diseases where bronchoscopy is part of establishing the diagnosis, such as chronic obstructive pulmonary disease (COPD), sarcoidosis, or lung cancer.
Introduction
肺是在与外部环境的连续接触，并且高度暴露于既无害颗粒和微生物有能力引起的疾病。因此，它是免疫系统装入针对入侵病原体有效的免疫反应的关键，但要保持耐受吸入抗原不引起疾病是同样重要的。为了提供有效的免疫监视，呼吸系统衬有免疫细胞，包括树突细胞（DC）的网络。 DC是专业的抗原呈递细胞与激活幼稚T细胞的独特能力。在人的肺部，驻留的DC遇到抗原，然后进程并将其输送到肺引流淋巴结以供呈现给和活化的T细胞1，2，3的。
在人类的免疫系统，DCS可分为几个子集，具有次方CT但重叠的功能：CD1C +和CD141 +骨髓DC（的MDC）和CD123 +浆的DC（PDC上）4，5。而在人DCs最详细的知识从血液中的研究茎，现在明显的是，人体肺部也怀有DC亚群与T细胞刺激能力6，7，8，9的罕见群体。然而，积累的数据表明，免疫细胞，包括树突状，不同在它们的频率，表型，和功能取决于它们的解剖位置10。因此，为了研究免疫细胞从相关组织，以了解它们对局部免疫和容忍的贡献是重要的。总之，这强调需要解决肺部疾病时，研究肺居民的DC，尽管血液DC是更容易使用和访问在人类。
在人类研究肺驻留的DC的首批研究采用免疫组织化学11，12，13主要依靠形态和单标记物，如HLA-DR和CD11c的表达，在组织切片。与此相反，最近的研究通常是在流式细胞依靠分析来研究不同的免疫细胞亚群。然而，由于很难找到唯一地标识特定的DC子集的单个细胞表面标记物，研究的潜在的限制施加仅四色流式细胞仪是包含具有类似表型标记如树突细胞群的风险。例如，CD11c的是在所有的骨髓DC和广大单核细胞表达。另一方面，在研究中采用更先进的流式细胞仪面板，从患者的外科手术切除非癌肺组织中通常使用外部参照“> 10，14，15，16，虽然目前还不清楚这些稀有人群是否真正代表的DC存在于正常人。总体而言，研究在很大程度上是由于一个事实，即手术切除或整个人类的肺组织是稀缺的限制。
为了克服这些限制，这项工作介绍了如何执行空间分布及区议会在从谁接受支气管镜检查健康志愿者获得支气管粘膜活检表型鉴定的详细分析。几个小活检可以从每个单独的收集和随后可以嵌入用于切片和免疫组织化学或酶促消化先进流式细胞分析分析。在从支气管镜检查获得的支气管活检的形式使用的肺组织赋予使得能够执行ST的优点UDY上健康的志愿者，不像肺部开放手术，对于明显的原因，被限制为那些需要开胸手术的患者。此外，从健康志愿者支气管期间被取样的组织是生理上正常的，而相比之下，肺组织的非患部患者肺部疾病。另一方面，在活检小和检索单元的汇集几个活检即使当数，限制了可进行分析的类型。
虽然目前的工作重点是对DC，描述可以直接扩展的方法，包括其他（免疫）利益驻留在人体黏膜肺组织细胞。此外，该协议也直接适用于从肺部疾病，其中支气管镜检查是确立诊断，如慢性阻塞性肺疾病（COPD），结节病，或者肺癌的一部分的患者获得的样品。
Protocol
Representative Results
Discussion
本文介绍了如何利用免疫组织化学生成健康人肺组织居民DC的详细的空间和表型鉴定和支气管镜检查期间收集支气管粘膜活检流式细胞仪。在以下各段中的协议的关键步骤中详细讨论。
关键步骤议定书
切片和免疫组化：这是至关重要的，当不使用它们（步骤2.5），以保持活检块在-20℃。温馨块有时会变得柔软，不会一节为好。此外，保持块在-20℃将保留抗?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
笔者想感谢谁临床资料已经促成了这一研究志愿者。我们也感谢工作人员在公共卫生与临床医学，医学/呼吸内科的科，大学医院，于默奥（Norrlands universitetssjukhus）部的所有临床资料的收集。
这项工作得到了补助金从瑞典研究理事会，瑞典心肺基金会，瑞典战略研究基金会，并卡罗琳斯卡医学院AS-S支持。
Materials
| Bronchoscopy | |||
| Bronchoscope BF1T160 | Olympus | BF1T160 | |
| Light source | Olympus | Exera CV-160 | |
| Fenestrated forceps | Olympus | FB21C | Used to take biopsies |
| Bite Block | Conmed | 1429 | 20x27mm |
| Glucose 25% | 500mL intravenous | ||
| Glycopyrronium bromide 0.2mg/mL | Intravenous. Prevents mucus/saliva secretion | ||
| Mixt. Midazolam 1mg/mL p.o | Can be used for extra relaxation | ||
| Lidocaine, 40mg/mL | Mouth and throat administration / Gargled | ||
| Lidocaine 100mg/ml spray | Administered to back of throat | ||
| Lidocaine 20mg/ml spray | Administered via bronchoscope to airways | ||
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| GMA processing and embedding | |||
| Glass vials | 5mL | ||
| Acetone | Sigma-Aldrich | 32201-1L | |
| Molecular sieves, 4A | Alfa Aesar | 88120 | 3-4mm diameter pellets |
| Phenylmethylsulfonyl fluoride | Sigma-Aldrich | P-7626 | 0.035g/100ml acetone |
| Iodoacetamide | Sigma-Aldrich | I-6125 | 0.37g/100ml acetone |
| Polythene-flat TAAB embedding capsules | TAAB laboratories | C094 | x500 8mm diameter, polythene, flat-bottom capsules |
| Capsule holder | TAAB laboratories | C054 | Holds 25 8mm capsules |
| JB-4 GMA embedding kit | Polysciences | 00226 | Contains JB-4 Solution A (0026A-800), JB-4 solution B (0026B-3.8), benzoyl peroxide (02618-12) |
| Methyl benzoate | Sigma-Aldrich | 27614-1L | |
| Silica gel with humidity indicator | Scharlau | GE0043 | 2.5-6mm |
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| GMA sectioning | |||
| Glass microscope slides | ThermoFisher Scientific | 10143562CEF | Cut edges, frosted end |
| Poly-L-Lysine solution | Sigma-Aldrich | P8920-500mL | 1:10 for working solution |
| Sheet glass strips for ultramicrotomy | Alkar | ||
| Tween 20 | Sigma-Aldrich | P2287 | Wash solution (0.1% Tween20) |
| LKB 7800B Knifemaker | LKB | ||
| Capsule splitter | TAAB laboratories | C065 | |
| Carbon steel single edge blades | TAAB laboratories | B054 | |
| Vice | |||
| Ammonia, 25% | VWR | 1133.1000 | 2mL in 1L, 1:500 (0.05%) |
| Microtome | Leica | Leica RM 2165 | |
| Light source | Leica | Leica CLS 150 XE | |
| Microscope with swing arm stand | Leica | Leica MZ6 | |
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| GMA Immunohistochemistry | |||
| Diamond tipped pen | Histolab | 5218 | |
| Hydrogen peroxide 30% solution | AnalaR Normapur | 23619.264 | |
| Sodium azide | Sigma-Aldrich | S8032 | |
| Tris | Roche | 10708976001 | |
| Sodium chloride | VWR chemicals | 27810.295 | |
| Bovine serum albumin | Millipore | 82-045-2 | Probumin BSA diagnostic grade |
| Dulbecco's modified eagle medium (DMEM) | Sigma-Aldrich | D5546 | |
| Anti-human CD45 antibody | BioLegend | 304002 | Mouse monoclonal, clone HI30, isotype IgG1k. Working concentration of 500 ng/ml |
| Anti-human CD1a antibody | AbD Serotech | MCA80GA | Mouse monoclonal, clone NA1/34-HLK, isotype IgG2a. Working concentration of 10 µg/ml |
| Mouse monoclonal IgG1 isotype control | Abcam | ab27479 | |
| Mouse monoclonal IgG2a isotype control | Dako | X094301-2 | |
| Vectastain ABC Elite standard kit | Vector Labs | PK-6100 | |
| AEC (3-amino-9-ethylcarbazole) peroxidase substrate kite | Vector Labs | SK-4200 | |
| Mayers haematoxylin | HistoLab | 01820 | |
| Permanent Aqueous Mounting Medium | AbD Serotech | BUF058C | |
| Drying oven | |||
| DPX permanent mounting solution | VWR | 360292F | |
| Light microscope | Leica | Leica DMLB | |
| Microscope camera | Leica | Leica DFC 320 | |
| Analysis software | Leica | Leica Qwin V3 | |
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| Enzymatic digestion | |||
| Hank's Balanced Salt Solution (HBSS) | Sigma-Aldrich | 55021C | |
| Dithiothreitol (DTT) | Sigma-Aldrich | DTT-RO | |
| Collagenase II | Sigma-Aldrich | C6885 | |
| DNase | Sigma-Aldrich | 10104159001 ROCHE | |
| RPMI 1640 | Sigma-Aldrich | R8758 | |
| Forceps | |||
| Platform rocker | Grant instruments | PMR-30 | |
| 50 mL conical tubes | Falcon | 14-432-22 | |
| 40 µm cell strainer | Falcon | 352340 | |
| Name of Reagent/ Equipment | Company | Catalog Number | Comments/Description |
| Flow cytometry | |||
| Phosphate Buffered Saline (PBS) | |||
| LIVE/DEAD Aqua fixable dead cell stain kit | Life Technologies | L34957 | |
| CD45 | BD | 555485 | |
| CD3 | BD | 557757 | |
| CD20 | BD | 335829 | |
| CD56 | Biolegend | 318332 | |
| CD66abce | Miltenyi | 130-101-132 | |
| HLA-DR | BD | 555813 | |
| CD14 | BD | 557831 | |
| CD16 | Biolegend | 302026 | |
| CD11c | BD | 560369 | |
| CD1c | Miltenyi | 130-098-009 | |
| CD141 | Miltenyi | 130-090-514 | |
| CD103 | Biolegend | 350212 | |
| Paraformaldehyde | Sigma-Aldrich | F8775 | |
| LSR II Flow cytometer | BD | Flow cytometer | |
| FlowJo | FlowJo | Software for analysis |
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