乙型肝炎病毒嗜肝结合位点与受体的研究进展

众多学者对HBV嗜肝性机制得出共识:HBV膜蛋白直接与肝细胞膜上相应的受体结合,继而膜融合,通过胞饮作用内吞入胞;或者HBV与细胞外液中某一中介分子结合形成复合体,再与肝细胞膜上其相应的受体结合入胞.但目前仍不能确定膜受体及中介分子是什么.现就近年来HBV嗜肝机制研究综述如下.     

散发性戊型肝炎肝组织细胞学观察

目的 观察散发性戊型病毒性肝炎组织细胞学特征。方法 收集18例散发性戊型病毒性肝炎穿刺肝组织进行详尽的光、电镜观察。结果 18例肝组织均呈急性肝炎的典型病变，较其它型病毒性肝炎相对特征性病变为：肝细胞变性明显，细胞连接面多数呈分离状态，毛细胆管微绒毛多数脱失，腔扩大，腔内存积细颗粒絮状物。病变重者，肝细胞核浓缩，粗面内质网（RER）扩张，核糖体脱失，被Kupffer细胞包围、吞噬，或坏死的肝细胞堕入窦周间隙，胞质内见多数溶酶体。变性乃至坏死的肝细胞旁常见淋巴细胞包围，且淋巴细胞伸出伪足状窦起与肝细胞接触，肝细胞往往出现胞膜部分脱失，浸润于肝细胞的淋巴细胞胞质中偶见圆形或杆状的致密颗粒。汇管区炎及周围炎突出，以淋巴细胞、浆细胞为主的单个核细胞向小叶内溢入。结论 散发性戊型病毒型肝炎有其相对病理学特征；细胞免疫性损伤可能是散发性戊型肝炎的主要肝损伤机制。     

乙型肝炎患者外周血T淋巴细胞亚群的检测

乙型病毒性肝炎(乙肝)的肝细胞损害和炎症反应是免疫细胞作用于肝细胞的结果,以T淋巴细胞破坏已感染乙型肝炎病毒(HBV)的肝细胞的作用最为重要.我们对乙肝患者外周血T淋巴细胞亚群和e抗原系统之间的关系进行了探讨.     

乙丁型肝炎病毒感染树鼠句肝组织Fas和ICE的表达

目的探讨乙型并丁型肝炎病毒感染树鼠句肝组织中Fas和ICE表达与HDV感染之间的关系。方法采用免疫组织化学技术对45份HDV/HBV感染树鼠句肝组织中HDAg、Fas和ICE的表达进行了检测。结果45份肝组织中有39份可检出Fas(阳性率86.7%),有43份可检出ICE(阳性率95.6%)。Fas和ICE在肝细胞质和(或)膜上表达,以肝细胞质内表达为主。HDAg表达与Fas和ICE表达之间有显著相关性(χ2值为29.2和36.2,P＜0.01),HDAg表达越强,Fas和ICE表达也越强。结论肝细胞内的HDAg表达可诱导Fas和ICE的表达。     

免疫性和酒精性肝纤维化大鼠肝脏细胞质膜的蛋白质组学研究

目的 研究肝纤维化的发生机制,寻找新的与肝纤维化相关的生物学标志物. 方法将48只大鼠分为乙醇组、免疫组和对照组,分别进行乙醇灌胃、猪血清注射与等渗盐水注射处理.采用James's网状染色法染色并检测处理后第2、4、6、8周大鼠肝脏的病理学变化.将处理后第2、4、6、8周的各组大鼠分别处死4只后取肝,并将肝脏组织作匀浆处理,通过2次蔗糖密度梯度离心获得细胞质膜组分,用Western blot法检测细胞质膜的纯度.提取肝脏细胞质膜蛋白质,通过双向凝胶电泳分析各个时期的大鼠肝脏细胞质膜蛋白质,差异蛋白质点在酶解后经戴安纳升级液相色谱Ultimate 3000串联布鲁克高容量离子阱质谱HCT进行鉴定.并对被鉴定的差异蛋白质进行功能和定位的分类分析. 结果大鼠肝脏细胞质膜得到了有效富集.双向凝胶电泳分析第2周和第8周的大鼠肝细胞质膜蛋白质,共找到87个差异蛋白质点,这些蛋白质点经过质谱鉴定后对应于30个非冗余蛋白质,包括膜联蛋白A2,细胞支架角蛋白8和18. 结论膜联蛋白A2、细胞支架角蛋白8和18等蛋白质可成为肝纤维化诊断的新标志物.     

疟原虫纳虫空泡膜功能及其相关蛋白的研究进展

疟疾是威胁全球人类健康的重要传染病之一。如何抑制疟疾的传播,仍然是一个亟待解决的问题。当疟原虫入侵宿主细胞后,会在胞内生长、繁殖,造成严重的病理损伤。而纳虫空泡膜作为宿主细胞与疟原虫直接接触的界面,对疟原虫生存状态有重要意义。本文简要介绍了疟原虫纳虫空泡膜的形成及其与疟原虫细胞质质膜、管状囊泡网络之间的关联,对红内期、肝内期与有性期纳虫空泡膜相关蛋白及其功能进行归纳总结,并对疟疾防治策略提出了展望。     

外泌体在白血病细胞增殖中的作用

<正>外泌体又被称为胞外体,是活细胞分泌在体液中的一种纳米级的、膜包被小泡,直径约为30~120 nm,表面富含胆固醇、神经鞘磷脂、神经酰胺等脂类物质,携带亲本细胞来源的蛋白质、mRNA、microRNA、DNA等分子信息,是细胞间信息交流与的物质传递的载体~([1~3])。外泌体来源于活细胞胞质内、晚期内吞体的膜性囊泡,其融合为多囊体后与细胞质膜融合释放到细胞外~([4])。外泌体广泛存在于血液、唾液、尿液、脑脊液以及胸水、腹水等体液中,不     

细胞间黏附分子-1/淋巴细胞功能相关抗原-1在乙型肝炎发病机制中的作用

目的　探讨细胞间黏附分子 1/淋巴细胞功能相关抗原 1(ICAM 1/LFA 1)在乙型肝炎发病机制中的作用。方法　用免疫组化检测 11例正常人和 70例HBV感染者肝内ICAM 1、LFA 1和CD8表达状况 ,并用免疫组化双重染色技术研究HBV感染者肝内ICAM 1与LFA 1双重表达状况。结果　在炎症坏死区 ,LFA 1阳性淋巴细胞浸润在ICAM 1阳性肝细胞周围 ,部分与ICAM 1阳性肝细胞紧密接触 ,LFA 1阳性淋巴细胞周围存在坏死细胞碎片和损伤的肝细胞。结论　ICAM 1/LFA 1参与介导淋巴细胞与肝细胞间黏附 ,在慢性乙型肝炎和重型乙型肝炎免疫发病机制中起重要作用。     

肝细胞治疗肝衰竭的机理及临床意义

近十余年来许多学者致力于肝细胞治疗实验性肝衰竭的研究,发现移植或输注肝细胞或再生肝胞质液(Cytosol)可显著提高肝衰动物的存活率。苏联和日本学者已将动物的肝细胞输入人体来代替失去功能的肝     

可活化诱导的淋巴细胞凋亡在乙型肝炎慢性化机制中的作用

目的 探讨可活化诱导的淋巴细胞凋亡在慢性乙型肝炎（乙肝）发病机制中的作用。方法 应用流式细胞仪对乙肝外周血淋巴细胞的凋亡进行检测，乙型肝炎病毒（HBV）DNA定量检测采用斑点杂交法。结果 与正常对照组比较，可活化诱导的淋巴细胞凋亡在慢性乙肝患者明显升高，而在重型肝炎则降低，差异有显著性；急性肝炎则无。可活化诱导的淋巴细胞凋亡在丙氨酸转氨酶（ALT）下降期明显高于上升期，但与肝内炎症分级并无明显相关性。乙肝外周血淋巴细胞的凋亡比例与血清HBV DNA含量呈正相关。结论（1）可活化诱导的淋巴细胞凋亡可能参与乙肝的慢性化；（2）外周血淋巴细胞的凋亡与血清HBV DNA水平有关。     

Hepatocellular expression of lymphocyte function-associated antigen 3 in chronic hepatitis.

T lymphocyte-mediated cytolytic immune reactions are considered a major cause of hepatocyte injury in chronic viral and autoimmune hepatitis. To further investigate local immune responses, we studied the expression of lymphocyte antigens and cell-cell interaction molecules known to be involved in effector-target cell interactions by light and electron microscopy in liver biopsy specimens from patients with chronic viral and autoimmune hepatitis. CD8+ lymphocytes were found to be the predominant population of cells in the inflammatory infiltrate in chronic hepatitis B and non-A, non-B hepatitis. In contrast, CD4+ cells constituted a comparably higher proportion of cells and were more numerous than CD8+ cells in chronic autoimmune hepatitis. In both viral and autoimmune hepatitis, a substantial portion of lymphocytes expressed activation antigens such as T11/3 (CD2R) and IL-2-R (CD25). Lymphocyte function-associated antigen-3 (CD58), which mediates lymphocyte adhesion and activation and is the natural ligand of the CD2/T11 lymphocyte surface receptor, could be demonstrated on endothelial cells and hepatocytes. Hepatocellular lymphocyte function-associated antigen-3 expression in chronic hepatitis showed membranous and cytoplasmic staining of hepatocytes and had a positive correlation with the degree of inflammatory activity. These results suggest that effector-target interactions between hepatocytes and lymphocytes mediated by the lymphocyte function-associated antigen-3/CD2 pathway play a role in chronic inflammatory liver disease. Possible functional consequences of this interaction include enhancement of antigen-specific immune reactions and antigen-independent mechanisms of T cell activation, which may contribute considerably to the degree of inflammatory activity and tissue damage in chronic hepatitis.     

Immunohistochemical investigation of hepatitis B virus associated antigens, HLA antigens and lymphocyte subsets in type B chronic hepatitis

HLA antigens, hepatitis B virus (HBV)-associated antigens and lymphocyte subsets in liver tissue from 35 patients with HBs antigenemia were studied using an immunoperoxidase double staining method and immunoelectron microscopy in order to clarify the immune mechanism of hepatocyte lysis in type B hepatitis. Immune light and electron microscopy using monoclonal antibodies to lymphocyte subsets revealed that infiltrating lymphocytes in the areas of piecemeal necrosis and focal necrosis were predominantly CD8-positive, showing direct contact with hepatocytes. In contrast, CD4(+) cells were infrequently observed in necrotizing inflammatory lesions. HLA-A,B,C antigens were mainly found on hepatocytes in areas of piecemeal necrosis and focal necrosis, in association with CD8(+) lymphocyte infiltration. HLA-DR antigens were demonstrated on a few hepatocytes in the same lesions. In cases of CAH with serum HBeAg positive, HLA-A,B,C, antigens and HBV antigens simultaneously demonstrated on the same hepatocytes. Especially, hepatocytes expressing both HLA-A,B,C antigen and HBsAg on the plasma membrane showed direct contact with CD8(+)lymphocytes. This finding fulfilled the morphological requirements for HBsAg as a target antigen. On the other hand, HBcAg was hardly demonstrated in the liver cell membrane but was demonstrated mainly in the cytoplasm. Compared with the nuclear localization of HBcAg in cases of NSR, cytoplasmic localization of this antigen may be associated with membranous expression of new antigens induced by HBV infection.     

Immunohistochemical investigation of hepatitis B virus associated antigens,HLA antigens and lymphocyte subsets in type B chronic hepatitis

HLA antigens, hepatitis B virus (HBV)-assodated antigens and lymphocyte subsets in liver tissue from 35 patients with HBs antigenemia were studied using an immunoperoxidase double staining method arid immunoelectron microscopy in order to clarify the immune mechanism of hepatocyte lysis in type B hepatitis. Immune light and electron microscopy using monoclonal antibodies to lymphocyte subsets revealed that infiltrating lymphocytes in the areas of piecemeal necrosis and focal necrosis were predominantly CD8-positive, showing direct contact with hepatocytes. In contrast, CD4(+) cells were infrequently observed in necrotizing inflammatory lesions. HLA-A,B,C antigens were mainly found on hepatocytes in areas of piecemeal necrosis and focal necrosis, in association with CD8(+) lymphocyte infiltration. HLA-DR antigens were demonstrated on a few hepatocytes in the same lesions. In cases of CAH with serum HBeAg positive, HLA-A,B,C, antigens and HBV antigens simultaneously demonstrated on the same hepatocytes. Especially, hepatocytes expressing both HLA-A,B,C antigen and HBsAg on the plasma membrane showed direct contact with CD8(+) lymphocytes. This finding fullfilled the morphological requirements for HBsAg as a target antigen. On the other hand, HBcAg was hardly demonstrated in the liver cell membrane but was demonstrated mainly in the cytoplasm. Compared with the nuclear localization of HBcAg in cases of NSR, cytoplasmic localization of this antigen may be associated with membranous expression of new antigens induced by HBV infection.     

Expression of leukocyte adhesion molecules in the liver of patients with chronic hepatitis B virus infection.

Virus-specific T-cell responses are believed to be involved in the pathogenesis of liver cell injury secondary to hepatitis B virus infection. In this study, liver biopsy specimens from patients with chronic hepatitis B virus infection were analyzed for expression of two major pathways of adhesion used by cytotoxic T cells to interact with target cells. The lymphocyte function-associated antigen 3 was found preferentially expressed on hepatocytes of patients with active hepatitis B virus replication, whereas the expression of the intercellular adhesion molecule 1 on hepatocytes seemed more closely related with inflammatory activity. Adhesion molecules were also highly expressed on T lymphocytes found in areas of piecemeal and spotty necrosis, indicating the presence of antigen-specific "memory" T cells at the site of hepatocellular injury. This study suggests that the expression of the lymphocyte function-associated antigen 3 on hepatocytes may be important for viral elimination. The coordinate expression of the intercellular adhesion molecule 1 may regulate inflammatory response and enhance viral antigen presentation to T cells. Conversely, the absence of hepatocyte adhesion molecules might be a favorable factor for viral persistence.     

Liver morphology in marmosets infected with epidemic non-A, non-B hepatitis in India

In this study the morphological changes in the livers of marmosets inoculated with stool extracts from epidemic non-A, non-B hepatitis patients in India were examined. The histologic changes of epidemic non-A, non-B hepatitis in marmosets consisted mainly of round cell infiltration in the portal tracts, spotty liver cell necrosis, sinusoidal lymphocyte infiltration, and Kupffer cell mobilization. By electron microscopy, liver cells from infected marmosets showed cisternal dilation of the endoplasmic reticulum, irregularly-shaped nucleus, and disorganization of the mitochondrial cristae. In some areas interaction of lymphocytes with hepatocytes was observed. Similar observations have been made in type B hepatitis infection, presumably due to liver cell damage mediated by immune mechanisms. The result of our study is also compatible with the interpretation that the liver cell damage in this experimental model may be mediated by immune mechanisms.     

Hepatic expression of intercellular adhesion molecule-1 (ICAM-1) in viral hepatitis B

The in situ distribution patterns of intercellular adhesion molecule-1 and human leukocyte antigen-DR antigens were studied in serial sections of 61 liver biopsy specimens from patients with hepatitis B virus infection using immunohistochemical techniques. In addition, the topographical relationship between the display of HBcAg on one hand and the expression of intercellular adhesion molecule-1 by hepatocytes on the other was analyzed with a double-staining immunohistochemical procedure in 14 selected liver biopsy samples showing chronic persistent or chronic active hepatitis and signs of active hepatitis B virus replication as reflected by the presence of variable amounts of HBcAg in a nuclear or cytoplasmic pattern of immunoreactivity. Coexpression of intercellular adhesion molecule-1 and human leukocyte antigen-DR antigens by hepatocytes correlated positively with the site and extent of the inflammatory infiltrate, which was composed of lymphocytes expressing lymphocyte function-associated antigen-1. In healthy HBsAg-positive carriers without inflammatory liver disease, no intercellular adhesion molecule-1 or human leukocyte antigen-DR expression was found on hepatocytes; in acute hepatitis, intercellular adhesion molecule-1 and human leukocyte antigen-DR were strongly expressed throughout the liver parenchyma on liver cell membranes and on sinusoidal lining cells. In chronic persistent and chronic active hepatitis and in active cirrhosis, intercellular adhesion molecule-1 and human leukocyte antigen-DR showed membranous positivity on focal clusters of hepatocytes in areas of periportal or intraacinar inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunoelectron microscopic observations on the inflammatory infiltrates and HLA antigens in hepatitis B and non-A, non-B

The present knowledge of the inflammatory reaction occurring in situ during hepatitis B favors a T cell-dependent MHC-restricted immune response. However, the reports in the literature are primarily based on the application of monoclonal antibodies directed at different lymphocyte subsets which discern only lymphocytic phenotypes and do not reflect the actual situation adequately. Therefore, we investigated the liver biopsies of patients with hepatitis B (28 patients) and non-A, non-B (21 patients) by immunoelectron microscopy with monoclonal antibodies directed at lymphocyte subtypes (pan-B, pan-T, T8, T4 and NKH1) and at activation epitopes (IL-2 receptor, TA1 and T11/3) as well, in order to determine the phenotype in association with the activation status of the lymphocytes that are in close contact with hepatocytes; thus, establishing an effector-target cell relationship on the ultrastructural level. We were able to confirm the central role of T8 lymphocytes being the predominant type of lymphocytes in close contact with liver cells in the space of Disse. A certain percentage of these cells expressed "activation" markers as IL-2 receptor, TA1 and T11/3. In acute hepatitis, the NK lymphocytes made up a fifth of all lymphocytes, whereas their number dropped below 10% in the chronic stage. There was a vague correlation between the inflammatory activity of the disease and the expression of HLA antigens (both classes I and II) on inflammatory cells and also on hepatocytes. The results did not show significant differences between hepatitis B and non-A, non-B.(ABSTRACT TRUNCATED AT 250 WORDS)     

T-lymphocyte cytotoxicity to HBsAg-coated target cells in hepatitis B virus infection

The cytotoxic effect of peripheral lymphocytes on chicken red blood cells (ChRBC) coated with purified hepatitis B surface antigen (HBsAg) has been studied as an in vitro parameter of cell-mediated immunity in acute and chronic infection with hepatitis B virus. Using this technique, the mean cytotoxic index of lymphocytes from patients with acute hepatitis B (29·13 ± 20·88) was significantly higher than that obtained with lymphocytes from control subjects (6·53 ± 3·75). Only 33·3% of the patients with HBsAg-positive chronic active hepatitis exhibited lymphocyte cytotoxicity to HBsAg-coated target cells and the mean cytotoxic index (11·66 ± 6·60) was in these cases significantly lower than that found in acute hepatitis B. Healthy chronic carriers of HBsAg failed to show lymphocyte cytotoxicity to target cells. The effector cells detected in acute hepatitis B by this in vitro assay have been demonstrated to be T-lymphocytes, as T-cell depleted subpopulations lacked cytotoxic activity. Target cell lysis could be blocked by addition of HBsAg-coated unlabelled ChRBC as well as of purified HBsAg in the culture tubes. It is suggested that damage to the liver cells in acute hepatitis B is related to the presence of cytotoxic T-lymphocytes reacting with HBsAg on the surface of infected hepatocytes. An inadequate lymphocyte response to the antigen may be responsible for the persistence of the infection in the liver with varied clinical manifestations and associated hepatic lesions.     

Immunohistochemical study of the distribution of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 in chronic type B hepatitis

The expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) in the livers of 11 patients with chronic hepatitis B was studied immunohistochemically by light and electron microscopy to clarify the role of these adhesion molecules in tissue damage in chronic hepatitis B. On hepatocytes, ICAM-1 expression was confined to the bile canalicular surface when the liver inflammation was mild. In contrast, when the liver inflammation was severe, ICAM-1 was distributed on the entire surface of the hepatocyte, including the sinusoidal and lateral membranes; lymphocytes which were mostly positive for LFA-1, were often observed invading deeply among these hepatocytes. The degree of ICAM-1 expression on the hepatocytes was also related to the expression of HLA class 1 antigen. In liver showing diffuse expression of ICAM-1 on the hepatocytes, strong expression of HLA class 1 antigen was observed, and amounts of HBV in the liver were decreased. Diffuse expression of ICAM-1 and HLA class 1 antigen was mostly observed after acute exacerbation of liver inflammation. These results suggest that the ICAM-1/LFA-1 pathway is involved in the immunological mechanism, responsible for liver cell damage in chronic hepatitis B.