胸腺小体在胸腺发育中的形态发生及其功能探讨

用组织化学与免疫组织化学技术对８例人胎的胸腺进行研究，观察在其发育过程中胸腺小体的形态变化有增殖细胞核抗原，花生凝集素和细胞角蛋白等的表达特征。结果显示：胸腺小体是在胸腺发育阶段由胸腺上皮细胞呈同心圆状排列而成，且胎儿胸中单个和融合状的胸腺小体部较成体胸明显增多。围成胸腺小体的上皮细胞从周边中央，角蛋白明显减少，增殖能力逐渐减弱，表现为逐渐退化的过程。证实胸腺小体是处理退变的上皮细胞的场所。另外，     

胸腺微环境及其作用

胸腺是Ｔ淋巴细胞分化发育的场所，胸腺微环境由胸腺基质细胞、细胞外基质和细胞因子等构成。在胸腺基质细胞中，上皮细胞最多，分布最广。上皮细胞的分化、成熟和增殖依赖于胸腺内发育阶段的各Ｔ细胞亚群。位于胸腺内不同区域的基质细胞在Ｔ细胞发育的不同阶段起重要作用。血胸屏障是胸腺微环境中一个特殊结构，前Ｔ细胞可通过粘附分子，在趋化因子等作用下穿过血胸屏障进入胸腺，在胸腺内完成其分化发育过程。     

人胎儿胸腺内CD80和癌胚抗原的表达及定位

目的 探讨人胎儿胸腺内CD80和癌胚抗原(CEA)的表达水平及定位与胎儿发育的关系. 方法自附属医院妇产科收集流产死亡的胎儿12例,其中,小于4个月的4例列为早期,5个月的8例列为晚期.早晚期标本各分为两等份,一份制备冷冻切片进行HE染色、α-醋酸萘酯酶(ANAE)组织化学染色、CD80及CEA免疫组织化学染色,另一份以Trizol提取蛋白后进行CD80的免疫印迹和CEA的酶联免疫吸附测定(ELISA)检测. 结果 早期胎儿胸腺髓质发育差,晚期胎儿胸腺CD80阳性网状上皮细胞可分为6型:Ⅰ型扁平细胞分布于被膜内面和小梁表面;Ⅱ型呈小星形分布于皮质内;Ⅲ型及Ⅳ型呈扁平状,位于皮髓质交界处;Ⅴ型呈大星形状,突起多而细长相连成网状;Ⅵ型位于哈氏小体.在胎儿胸腺髓质网孔处可见ANAE点型(CD+CD8-)和散粒型(CD4-CD8+)细胞各呈丛状分布.早期组CEA阳性分布于髓质上皮细胞和哈氏小体,晚期组CEA阳性更集中于哈氏小体.CD80的免疫印迹和CEA的ELISA检测皆显示晚期组表达高于早期组. 结论 研究结果提示,人胎儿胸腺内CD80和CEA的表达及定位与胎儿胸腺细胞的发育及功能密切相关.     

化生性胸腺瘤临床病理分析

目的探讨化生性胸腺瘤的临床病理特点。方法应用光镜、免疫组织化学(EnVision法)染色[单克隆抗体选用AE1/AE3、波形蛋白、上皮膜抗原(EMA)、CD3、CD5、CD20、CD34、CD57、CD99、末端脱氧核苷酸转移酶(TdT)、HMBE-1、calretinin、p53和Ki-67]和透射电镜观察3例化生性胸腺瘤的组织学特点、免疫学表型和超微结构。结果3例化生性胸腺瘤均为女性,年龄为33、58和45岁。组织学表现为双相分化特征,上皮细胞区域与梭形细胞区域交错分布并相互移行。上皮细胞区域的细胞轻度异型,有核沟和核内假包涵体,核分裂象罕见,呈岛状和条索状排列并相互吻合;梭形区域细胞形态温和,未见核分裂象,排列成束状或席纹状结构。免疫组织化学染色:上皮细胞区域AE1/AE3强阳性表达,不表达波形蛋白和CD5,Ki-67指数3%~5%;梭形细胞区域波形蛋白弥漫表达,EMA阳性,不表达CD5和CD20;间质淋巴细胞CD3阳性,不表达TdT和CD99。超微结构示上皮细胞区域细胞间有桥粒和半桥粒结构,而梭形细胞区域缺乏。结论化生性胸腺瘤是一类罕见的具有独特临床病理特征的良性或低度恶性胸腺上皮来源肿瘤。     

实验性糖尿病大鼠胸腺的免疫组化研究

<正> 胰岛素依赖型糖尿病的发病与胸腺T细胞亚群分化异常有关,但对其在发病过程中的分化规律和作用机理尚未完全清楚.本实验给予SD大鼠一次性腹腔注射链脲佐菌素(STZ,65mg/kg)以诱导实验性糖尿病,做常规形态学及免疫组织化学染色观察实验性糖尿病状态下大鼠胸腺的形态结构、胸腺上皮细胞角蛋白(CK)表达及胸腺细胞表面CD4、CD8分子表达的变化.结果表明:本实验所诱导的实验性糖尿病大鼠均均出现典型的糖尿病症状,血糖值均在20.25mmol/L以上,远高于糖尿病大鼠的血糖标准值16.0mmol/L,说明本实验所用的建模方法效果较好.糖尿病大鼠胸腺发生病理性萎缩,CK8+的胸腺皮质上皮细胞相互联结构成的网中存在空洞状缺失,胸腺细胞表面的CD4、CD8表达呈区域状分布,主要分布于胸腺皮质部,髓质部较少见阳性反应细胞.结论:STZ诱导的实验性糖尿病大鼠伴有胸腺萎缩、胸腺皮质上皮缺失及胸腺细胞表面CD4、CD8的表     

化生性胸腺瘤2例临床病理分析

目的：探讨化生性胸腺瘤的临床及病理学特征。方法：应用光镜及免疫组织化学方法观察2例化生性胸腺瘤的组织学特点及免疫学表型,并复习相关文献。结果：2例均为男性,年龄55岁及56岁。组织学肿瘤显示双相分化特点,上皮细胞区域与梭形细胞区域交错分布并相互移行。上皮细胞呈相互吻合的束状、岛状及宽大的梁状排列,细胞轻度异型,可见核沟及核内假包涵体,偶见核分裂像;梭形细胞呈短束状或席纹状排列,细胞温和,未见核分裂像。免疫表型：上皮细胞区域CK19和AE1/AE3呈强阳性表达,上皮膜抗原（epithelial membrane antigen,EMA）弱阳性;梭形细胞区域表达Vimentin、Bcl-2及CD99,AE1/AE3局灶阳性,EMA弱阳性。两种区域中Ki67指数均〈5%。间质淋巴细胞CD3、CD5、CD20阳性,不表达Td T和CD99。结论：化生性胸腺瘤是一种罕见的良性或低度恶性胸腺肿瘤,诊断依靠病理组织学和免疫组织化学标记,完整切除预后良好。     

mLAIR-1分子在小鼠胸腺中的分布

目的 研究mLAIR-1分子在小鼠胸腺中的分布.方法 RT-PCR法检测mLAIR-1基因在正常小鼠胸腺细胞的表达,通过流式细胞术分析mLAIR-1在胸腺细胞发育不同阶段表达的变化,并采用免疫组织化学染色从形态学上观察mLAIR-1在胸腺的分布.结果 RT-PCR和流式细胞术的结果表明mLAIR-1在小鼠胸腺中有表达,尤其是在CD4-CD8-双阴性和CD4-CD8 单阳性阶段表达水平较高.免疫组化的结果显示该分子在胸腺的皮质区和髓质区均有表达,在皮髓质交界处以及髓质区表达更为明显.结论 mLAIR-1在小鼠胸腺细胞上有着明确的分布,并且在胸腺细胞分化发育的不同阶段具有不同的表达格局,提示该分子在胸腺的发育过程中可能有比较重要的作用.     

胸腺上皮细胞的发育分化及其分子调控

T细胞在胸腺中发育成熟依赖特殊的微环境,而胸腺上皮细胞(TECs)是微环境中最重要的成分之一.TECs主要分为皮质上皮细胞(cTECs)和髓质上皮细胞(mTECs),分别介导胸腺细胞的阳性选择和阴性选择过程.cTECs和mTECs来源于共同的胸腺上皮干细胞(TEPCs),经过一系列发育过程,最终分化为功能及表型成熟的TECs.TECs发育分化过程除受到自身内在基因如转录因子Foxn1和Aire的调控以外,还需要与间质细胞、胸腺细胞相互作用,接受外源信号如TNFR家族成员RANK、CD40和LTβR信号的调节,这些信号尤其对mTECs的发育至关重要.而成纤维细胞生长因子(FGFs)和Wnt通路则对TECs的扩增和功能维持非常重要.本文综述了TECs发育分化过程以及参与调控该过程的信号分子通路.     

胸腺上皮细胞的起源与分化

胸腺提供复杂的微环境来调节T细胞的存活、分化、选择和迁移,是T细胞发育、分化和成熟的场所也是自身免疫耐受的中心。胸腺上皮细胞包括胸腺皮质上皮细胞和髓质上皮细胞,其来源于内胚层,并由胸腺上皮祖细胞分化而来。胸腺上皮细胞的分化空间结构的建立有赖于转录因子和信号通路分子在胸腺上皮细胞不同时段复杂的分子调控。胸腺上皮细胞成熟过程也是胸腺上皮细胞一系列特异性表面标记分子的变化过程,对胸腺上皮细胞特异标记分子的研究是分析胸腺上皮细胞复杂分化过程的重要工具。本文重点探讨胸腺上皮细胞起源发展模型及分化过程中分子调控作用,以期更好的理解胸腺上皮细胞如何成为能够支持T细胞分化的特异哺育者。     

乳腺癌转移至胸腺瘤内一例

胸腺瘤是前纵隔内常见的原发肿瘤,但是其内继发肿瘤转移比较罕见。现报道1例发生于前纵隔的瘤对瘤转移——乳腺癌转移至B2型胸腺瘤内。患者女,55岁,因"发现纵隔肿物2年,近期肿物增大1个月"就诊。肿物最大径6 cm,有包膜,灰白色、实性、质地坚实。显微镜下,绝大部分区域形态符合B2型胸腺瘤,即在大量未成熟淋巴细胞背景上散在巢团状分布肿瘤性上皮细胞,上皮细胞呈圆形或多角形,细胞核大而疏松,可见核仁。但局部可见形态与以上形态完全不同的小灶上皮细胞巢,巢内细胞较胸腺瘤上皮细胞大,呈圆形或多边形,异型性明显,核质比大,染色质粗糙,核仁明显,免疫组织化学表达广谱细胞角蛋白、细胞角蛋白7、雌激素受体、GATA3和GCDFP15,且上皮细胞膜抗原部分阳性。诊断为(前纵隔)乳腺癌转移至B2型胸腺瘤内。     

Thymic epithelial cells expressed unusual follicular dendritic cell markers: thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue

Described herein is a case of thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. Using immunohistochemical double staining it was found that most of the thymic lymphoid follicles in this case possessed cytokeratin-positive and follicular dendritic cell (FDC) marker-positive cells. Moreover, using immunoelectron microscopy it was confirmed that some of the double-positive cells were thymic epithelial cells. The candidate of cytokeratin subtype expressed on the double-positive cells was cytokeratin 1 (CK1), which was expressed only by the epithelium of Hassall's corpuscles in thymuses from age-matched patients with myasthenia gravis. The present case indicates a possibility that some thymic epithelial cells become FDC, although it was uncertain whether they were derived from the epithelia of Hassall's corpuscles or whether they were at the same differentiation stage as Hassall's corpuscles.     

Localization of HIV-1 in human thymic implant in SCID-hu mice after intravenous inoculation

Human immunodeficiency virus type 1 (HIV-1) was immunohistochemically and ultrastructurally localized in human thymus implants in SCID-hu mice 3 weeks after intravenous (i.v.) inoculation of the virus. A viral antigen (gp120) was predominantly distributed in and around the epithelial cells in Hassall's corpuscles as demonstrated by fluorescence immunohistochemistry. Occasional solitary round cells positive for the viral antigen but negative for cytokeratin were detected in the perivascular areas. Ultrastructural examinations clearly revealed a number of mature viral particles in the intercellular spaces of the Hassall's corpuscles. Thus the present study indicates the possibility that thymic epithelial cells in Hassall's corpuscles act as a target and/or reservoir in an early stage of HIV infection.     

Establishment of a murine thymic epithelial cell line capable of inducing both thymic nurse cell formation and thymocyte apoptosis

A thymic epithelial cell (TEC) line (B/c. TEC-L1) was established from a normal thymus of a 4-week BALB/c mouse. The B/c. TEC-L1 had an epithelial morphology showing a contact-inhibited cobblestone-like arrangement with occasional desmosome-like structures at the adjacent cellular membranes. B/c.TEC-L1 cells showed positive staining for desmosomal glycoprotein, cytokeratin, thymosin alpha 1 beta 3, and I-Ad, and MHC class I antigens. The doubling time was 24 hours, and the chromosome number ranged from 52 to 78 with the mode of 70. Coculture of B/c.TEC-L1 cells with syngeneic, peanut agglutinin-agglutinated (PNA+) thymocytes in suspension at 37 degree C was followed by the formation of TEC thymocyte rosettes, after which the reconstitution of thymic nurse cells ensued. At 4 degrees C, PNA+ thymocytes bound to the B/c.TEC-L1 cell but did not form thymic nurse cells. PNA- thymocytes, although to a lesser degree than PNA+ cells, bound to the TECs at 37 degrees C, but at 4 degrees C few cells bound to the TECs. Allogeneic thymocytes also bound to the TECs at 37 degrees C. When the PNA+ thymocytes were cultured on the B/c.TEC-L1 monolayer, the small ones chiefly adhered on the surface of the TECs, while underneath the TECs the relatively large thymocytes (including cells in mitosis) predominated. Although the PNA- thymocytes bound to the surface of the monolayer within a few hours after coculture, by 24 hours nearly all cells disappeared. It is presumed that the thymocytes creeping underneath the B/c.TEC-L1 monolayer and those enveloped within the thymic nurse cell reconstituted in the suspension culture; both may be placed in circumstances analogous to the thymic microenvironment, wherein immature thymocytes appear to contact TECs directly and to be exposed to higher concentrations of thymic hormones and other soluble factors. Additionally, cell death in the PNA+ thymocytes was also observed in the coculture with B/c.TEC-L1 cells. The PNA+ cells revealed the morphological changes termed "apoptosis" characterized by chromatin condensation and nuclear fragmentation.     

Immunohistochemical demonstration of H antigen, peanut agglutinin receptor, and Saphora japonica receptor expression in infant thymuses and thymic neoplasias.

Ten infant thymuses and 13 primary thymic tumors obtained from archived paraffin-embedded tissue were examined for the presence of tissue blood group O antigen (H), peanut agglutinin receptor antigen (PNA-r), Saphora japonica agglutinin receptor antigen (SJA-r), carcinoembryonic antigen (CEA), cytokeratin (CK), and epithelial membrane antigen (EMA). In the thymuses studied, Hassall's corpuscles contained abundant immunoreactive CK, PNA-r, and H antigens, whereas CEA, SJA-r, and EMA were present focally in Hassall's corpuscles. Immunoreactive CK, PNA-r, and CEA were demonstrated focally in the subcapsular region, cortical nurse cells, and subcapsular-perivascular monocytic cells, respectively. PNA-r was present in all 12 epithelial type tumors, including all eight thymomas. CEA was present in nine tumors, including six thymomas. Six thymomas contained H antigen and SJA-r; five continued CK and EMA. SJA-r and EMA were also present in one carcinoid tumor of thymic origin. In epithelial thymomas, the antigens stained nests of epithelial cells resembling the pattern of staining in Hassall's corpuscles. Membrane staining of spindle cells of both spindle cell and epithelial thymomas was less intense than staining of epithelial type cells.     

Identification of acid cysteine proteinase inhibitor (cystatin A) in the human thymus

Background: Acid cysteine proteinase inhibitor (ACPI, also called cystatin A) is a protein that is present in the epithelial cells of the skin and in the dendritic reticulum cells of lymphoid tissues. In this study the presence and cellular localization of ACPI in the thymus was investigated. Methods: The cellular and topographical location of ACPI was immunohistochemically demonstrated in the normal thymus of man. Results: ACPI was found in the cells of the-Hassall's corpuscles and in many medullary cells. Most of these cells were epithelial cells, as shown by the results of immunohistochemical cytokeratin and epithelial membrane antigen stainings. Also, some individual cytokeratin negative but S-100 positive medullary reticular dendritic cells were stained with ACPI. Conclusions: The finding that ACPI is constantly present in the thymus at restricted and specific cellular locations leads to the suggestion that protease inhibitors may play a role in specific thymic functions. © 1994 Wiley-Liss, Inc.     

The cytoarchitecture of the human thymus detected by monoclonal antibodies

Seven monoclonal antibodies were produced against human thymic stromal cells. The monoclonal antibodies were put into two groups depending on whether the cells they detected were keratin-positive or -negative. Demonstrated in the keratin-negative group were a granular reticular meshwork, a stellate population predominantly in the medulla, and secretory cells associated with Hassall's corpuscles. In the keratin-positive group we showed two extensive epithelial networks, a trabecular and rare medullary epithelial population, and thymus-specific epithelium restricted to the subcapsule and the medulla. A novel finding was that some of the monoclonal antibodies and also OKM1 identified keratin-negative cells within Hassall's corpuscles, which implies that there are macrophages associated with these structures. The monoclonal antibodies should prove useful for separating and classifying subpopulations of stromal cells and also for monitoring changes in the thymic architecture in different thymic pathologies.     

Primary polyoma virus-induced murine thymic epithelial tumors. A tumor model of thymus physiology.

Thymic tumors were induced in C3'/Bittner mice by neonatal inoculation with polyoma virus. The objective of this study was to identify the phenotypes of the cells within the tumors and to attempt to determine the origin of the neoplastic cell population(s). At the ultrastructural level, the neoplastic cells resembled normal thymic epithelium with tonofilaments and desmosomes. Immunoperoxidase staining demonstrated the presence of cytokeratin, Iak, -beta 2-microglobulin, -asialo-GM1, the thymic cortical epithelial marker ER-TR4, and the medullary epithelial marker ER-TR5. Islands of normal cortical thymocytes supported by residual normal cortical epithelium and acid phosphatase-positive cortical macrophages were interspersed in the tumors. Residual islands of normal medullary architecture with nonspecific esterase-positive IDCs were rarely identified in tumors. Most lymphocytes in the tumors were normal immature cortical thymocytes with the phenotype Tdt+, PNA+, Thy 1.2bright, Ly-1dull, H-2Kkdull, ThB+, J11d+, and Lyt-2+L3T4+. Lymphocytes in the tumors were steroid-sensitive like normal thymocytes. The proportions of Lyt-2+L3T4- and Lyt-2-L3T4+ cells were generally larger in the tumors than in normal thymus and reflected the higher frequency of lymphocytes in the tumors capable of proliferating in vitro in response to Con A plus IL-2. The data were consistent with the hypothesis that the neoplasia originates from thymic epithelium that is interspersed with normal, developing thymic lymphocytes.     

Structural heterogeneity and immunohistochemical profile of Hassall corpuscles in normal human thymus.

The study was conducted on 27 specimens of normal thymus, removed during surgery for cardiovascular malformations. Biopsies were processed using current histological techniques, and the samples were stained using morphological and immunohistochemical methods (cytokeratin profile, vimentin, S100, CD45, CD20, CD3, CD68, CD34 protein, chromogranin A, neuronal-specific enolase, desmin). Microscopic examination focused on the structure and immunohistochemical profile of Hassall corpuscles, beginning from the hypothesis that the epithelial cells of these structures, characteristic for the thymus, participate in the negative and positive selection of thymocytes. Morphological assessment revealed the existence of four different types of Hassall corpuscles: juvenile, immature, mature and senescent. The lymphocyte-rich variant was identified in 25.92% of the cases with ages ranging between 7 days and 12 years. From the immunohistochemical point of view, the following reactions were negative: cytokeratins 7 and 8, vimentin, desmin, CD3, CD68, CD34 and neuron-specific enolase. Isolated positive chromogranin cells were found in two cases, and positive intracorpuscular CD20 cells in one case. Polyclonal cytokeratins were positive in all instances in the epithelial cells of the Hassall corpuscles, with higher intensity in high-molecular weight cytokeratin, strongly expressed in mature corpuscles. All specimens had positive S100 cells in the corpuscles, distributed among the epithelial cells, with dendritic morphology, in great numbers in juvenile and immature forms. Morphological and immunohistochemical results (corpuscle variants, the presence of positive S100 cells, concentration of positive CD20 and CD3 cells around the corpuscles) suggest the active involvement of epithelial cells of Hassall corpuscles in modulating the differentiation of thymocytes at the medullar level, a process that is mediated by protein S100 positive corpuscular dendritic cells.     

小牛胸腺激肽在体外对小鼠胸腺细胞表面花生凝集素受体的影响

本文报道用异硫氰酸荧光素标记的花生凝集素(FTTC-PNA)来测定经小牛胸腺激肽诱导后小鼠胸腺细胞表面PNA受体的变化。小牛胸腺激肽与胸腺细胞在完全RPMI-1640培养液中,置37℃温育20小时,随后洗涤细胞两次,加FITC-PNA,置0～4℃保温2小时,再洗涤以除去未结合的FITC-PNA,用半乳糖与胸腺细胞上的FITC-PNA结合并使之洗脱下来,最后用MPF-4荧光分光光度计测定荧光度,以表示结合在细胞PNA受体上FITC-PNA的量,从而反映PNA受体的变化情况。我们研究了胸腺激肽与胸腺细胞的温育时间、不同剂量及酸、碱、热和酶处理后的胸腺激肽对PNA受体的影响。且比较了小牛脾、肾制剂和胸腺激肽的生物活性。实验结果得出经胸腺激肽温育后的胸腺细胞,其表面FITC-PNA的结合量要比对照组降低16～19％。     

Cytoskeletal proteins in thymic epithelial cells of the Australian lungfish Neoceratodus forsteri

The vertebrate thymus consists of distinctive subpopulations of epithelial cells that contain a diverse repertoire of cytoskeletal proteins. In this study of the thymus in the Australian lungfish, Neoceratodus forsteri , immunohistochemistry was used to distinguish the cytoskeletal proteins present in each class of thymic epithelial cell. A panel of antibodies (Abs), each specific for a different cytoskeletal polypeptide (keratins, vimentin, desmin, actin and tubulins), was used on paraffin and ultrathin resin sections of thymus. Ab AE I (reactive against human type I cytokeratins (CK) 14, 16 and 19) selectively stained the cytoplasm of capsular, trabecular and the outermost epithelial cells of Hassall's corpuscles. Anti-CK 10 Abs strongly labelled the capsular epithelial cells and less than 20% of cortical and medullary epithelial cells. The anti-50-kDa desmin Ab did not react with any thymic cells, whereas the anti-53-kDa desmin Ab labelled some capsular, cortical and medullary thymic epithelial cells. The anti-vimentin Ab stained most of the capsular and ~60% of the cortical epithelium. Thymic nurse cells and Hassall's corpuscles were found to be devoid of actin, which was strongly detected in medullary and perivascular epithelium. Both α and β tubulins were detected in all thymic cells. This study extends the concept of thymic epithelial heterogeneity. The complexity of thymic epithelium in N. forsteri may indicate a relationship between thymic epithelial subpopulations and the thymic microenvironment. These data identify anti-keratin Abs as a valuable tool for studying differentiation and ontogeny of the thymic epithelium in N. forsteri .