首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 442 毫秒
1.
Human hepatitis B virus (HBV) is a member of the family Hepadnaviridae, and causes acute and chronic infections of the liver. The hepatitis B surface antigen (HBsAg) contains the large (L), middle (M), and small (S) surface proteins. The L protein consists of the S protein, preS1, and preS2. In HBsAg, the preS domain (preS1 + preS2) plays a key role in the infection of hepatocytic cells by HBV and has several immunogenic epitopes. Based on these characteristics of preS, several preS-based diagnostic and therapeutic materials and systems have been developed. PreS1-specific monoclonal antibodies (e.g., MA18/7 and KR127) can be used to inhibit HBV infection. A myristoylated preS1 peptide (amino acids 2-48) also inhibits the attachment of HBV to HepaRG cells, primary human hepatocytes, and primary tupaia hepatocytes. Antibodies and antigens related to the components of HBsAg, preS (preS1 + preS2), or preS1 can be available as diagnostic markers of acute and chronic HBV infections. Hepatocyte-targeting delivery systems for therapeutic molecules (drugs, genes, or proteins) are very important for increasing the clinical efficacy of these molecules and in reducing their adverse effects on other organs. The selective delivery of diagnostic molecules to target hepatocytic cells can also improve the efficiency of diagnosis. In addition to the full-length HBV vector, preS (preS1 + preS2), preS1, and preS1-derived fragments can be useful in hepatocyte-specific targeting. In this review, we discuss the literature concerning the applications of the HBV preS domain in bio- and nanotechnology.  相似文献   

2.
Insights into the early infection events of the human hepatitis B (HBV) and hepatitis delta virus (HDV) have been limited because of the lack of a cell culture system supporting the full replication cycle for these important pathogens. The human hepatoma cell line HepaRG allows the experimental induction of a differentiated state, thereby gaining susceptibility toward HBV and HDV infection. We recently identified HBV envelope protein-derived lipopeptides comprising amino acids 2 though 48 of the preS-domain of the L-surface protein, which block infection already at picomolar concentrations. To map the responsible sequence for the peptides' activity we describe an Escherichia coli expression system that permits myristoylation and investigated recombinant HBVpreS-GST fusion proteins with deletion- and point-mutations for their ability to prevent HBV and HDV infection. We found that (1) a myristoylated HBVpreS/2-48-GST fusion protein efficiently interferes with HBV infection of HepaRG cells; (2) deletions and point mutations in the highly conserved preS1 sequence between amino acids 11 through 21 result in the loss of infection inhibition activity; (3) hepatitis B viruses carrying single amino acid exchanges within this region lose infectivity; and (4) HDV infection of HepaRG cells can be inhibited by myristoylated HBVpreS peptides with the same specificity. In conclusion, HBV and HDV use at least one common step to enter hepatocytes and require a highly conserved preS1-sequence within the L-protein. This step is exceptionally sensitive toward inactivation by acylated HBVpreS1 peptides, which therefore represent a novel group of entry inhibitors that could be used for the treatment of hepatitis B and D.  相似文献   

3.
Hepatitis B virus (HBV), the prototype of the family Hepadnaviridae is an organ and species-specific human pathogen. Although our knowledge about the molecular biology of this highly liver-specific virus has increased, the mechanism of attachment and entry into its host cell, the differentiated hepatocytes is still enigmatic. Numerous potential cellular binding sites for the 3 HBV-surface proteins have been described in the past, but none of them have been proven to be a functional receptor. The difficulty in studying attachment and entry of HBV was mainly due to the lack of an easily accessible in vitro infection system. For over 20 years, primary human hepatocytes from surgically excised liver specimens were the only in vitro model, while the available hepatoma cell lines were not susceptible to HBV. Surprisingly, primary hepatocyte cultures from Tupaias (tree shrews) turned out to be susceptible for HBV. Using Tupaia hepatocytes we were able to determine the neutralising capacity of monoclonal and polyclonal antibodies against HBV. Mapping of the neutralising epitopes and inhibition of infection by competing preS1 lipopeptides enabled us and others to identify amino acids 9-18 of the preS1 domain as conserved minimal attachment site and amino acids 28-48 as accessory binding sites. Based on these data it should be possible to identify the cellular receptors for this attachment site. Furthermore we could distinguish between preS1-dependent attachment and subsequent S domain-dependent steps in the infection process. Not all S-binding antibodies are able to neutralize the infectivity. This should be considered when the protective efficacy of HBV vaccine induced antibodies is determined.  相似文献   

4.
The T-cell response to hepatitis B virus envelope antigens was studied in 11 hepatitis B vaccine recipients; 7 were selected to analyze the fine specificity of the T-cell response to the preS1 antigen. Four distinct T-cell epitopes were identified by peripheral blood lymphomononuclear cell stimulation with a panel of short synthetic peptides covering the preS1 sequence. The immunodominance of the preS1 epitopes included within peptides 21-30 and 29-48 was shown by their capacity to restimulate an HLA class II restricted proliferative response of T cells primed with the whole preS1 antigen. Conversely, peptide-specific T cells selected by peripheral blood lymphomononuclear cell stimulation with peptides 21-30 and 29-48 were able to recognize the native preS1 molecule, confirming that these epitopes are actually generated by the intracellular processing of preS1. Finally, amino acid residues essential for T-cell activation by peptide 21-30 were identified using 10 analogues of the stimulatory peptide containing single alanine substitutions. These results may be relevant to the design of efficient synthetic vaccines against hepatitis B virus infection.  相似文献   

5.
NACA as a Potential Cellular Target of Hepatitis B Virus PreS1 Protein   总被引:3,自引:0,他引:3  
The mechanisms of the attachment and penetration of hepatitis B virus remain obscure. It has been demonstrated that the preS1 region is essential for viral assembly and infectivity, however, as its cellular receptor has still not been identified unequivocally, we used a yeast two-hybrid system to screen the cellular proteins that can interact with preS1 protein. The protein recovered from a human liver cDNA library was nascent polypeptide-associated complex α polypeptide. The interaction between preS1 and nascent polypeptide-associated complex α polypeptide was verified by mating experiment and coimmunoprecipitation of COS7 cell lysates expressing both proteins. Based on these results, we speculate that nascent polypeptide-associated complex α polypeptide is a functional target of hepatitis B virus preS1 protein in cells.This work was supported by Grant C0310018 from the Natural Science Foundation of Fujian Province.Dan Li and Xiao Zhong Wang contributed equally to this work.  相似文献   

6.
The immunopathogenesis of hepatitis B e antigen (HBeAg) negative chronic hepatitis B (CHB) virus (HBV) infection has not been adequately investigated. We studied the cellular immune responses of peripheral lymphocytes using proliferating assays, intracellular cytokine staining (ICS) and ELISPOT interferon-gamma (IFN-gamma) assays after non-specific and specific stimulation with whole HBV proteins and synthetic peptides. Thirty patients with HBeAg negative CHB, eleven HBsAg inactive carriers, nine patients with acute hepatitis B and 22 healthy controls were included in the study. Patients with HBeAg negative CHB demonstrated an increased number of peripheral CD8+ T cells while their peripheral blood mononuclear cells showed increased proliferation after in vitro stimulation with overlapping hepatitis B core derived peptides and an envelope derived epitope (HBs 182-191 aa), similar to those observed in acute hepatitis B. Using ICS, we found an expanded population of IFN-gamma producing T lymphocytes, CD4+ and CD8+, after non-specific stimulation, in HBeAg negative CHB compared to all other groups. HBeAg negative CHB and acute hepatitis B patients had a similarly increased number of core specific T cells measured by the IFN-gamma assays. Inactive HBsAg carriers showed minimal proliferative responses overall while they exhibited an increased number of envelope specific effector T cells (measured by ICS). In conclusion, we showed that overall CD4+ T cell responses from patients with HBeAg negative CHB were comparable to those of acute hepatitis B, while inactive HBsAg carriers despite their limited proliferative capacity the effector activity of their peripheral T cells was maintained.  相似文献   

7.
乙型肝炎病毒表面抗原一级结构多态性的初步研究   总被引:8,自引:3,他引:5  
目的 研究慢性乙型肝炎患者体内乙型肝炎病毒(HBV)表面抗原一级结构的多态性。方法 设计特异性引物,自7例慢性乙型肝炎患者血清中扩增S基因全长或全基因组片段,TA克隆法克隆到T载体中,随机选择克隆测序。结果 共20个克隆被测序。20个克隆全S蛋白的总一致率仅为32.0%,13株全长为401氨基酸残基的克隆氨基酸一致效率为82.5%。患者血清中发现2株克隆编码截短型表面抗原中蛋白,在前S1或前S2的免疫决定区或可能的肝细胞结合部位均发现缺失突变。结论 慢性乙肝患者体内存在HBV准种群,病毒编码的截短型表面抗原中蛋白可为HBV诱导原发性肝癌提供一种途径,应加强对HBsAg一级结构多态性的研究。  相似文献   

8.
Hepatitis B virus (HBV) infection is still a major public health problem worldwide. Although much information about the molecular biology of HBV has been gained in the last decades, little is known about the mechanism of attachment and penetration of the HBV particle into human hepatocytes. The HBV envelope proteins are important for the interaction between the HBV particle and the hepatocyte plasma membrane. Although initially it was suggested that the preS2 domain could act, via polymerized human serum albumin, as an attachment site to human hepatocytes, in recent years other observations showed that the preS1 domain is probably the most important attachment site to human hepatocytes. However, controversial findings on cellular proteins for binding to the preS1 domain has been described, namely the IgA-, the IL6-, the asialoglycoprotein receptor and GAPD. Although the preS1 attachment site may be important, apo H has been shown to bind specifically to small HBsAg. Recently, we have identified human liver Annexin V as a specific small HBsAg-binding protein. In a preliminary report, the direct involvement of human Annexin V in the initial step of HBV infection has been desmonstrated. A rat hepatoma cell line, which does not express human Annexin V and which is not infectable by HBV, gained the ability to become infected by HBV after transfection with human Annexin V. This result may facilitate the progress of HBV receptor research and elucidate the molecular mechanism of the initial step of HBV infection.  相似文献   

9.
The Myr47 lipopeptide, consisting of hepatitis B virus (HBV) pre-S1 domain (myristoylated 2–48 peptide), is an effective commercialized anti-HBV drug that prevents the interaction of HBV with sodium taurocholate cotransporting polypeptide (NTCP) on human hepatocytes, an activity which requires both N-myristoylation residue and specific amino acid sequences. We recently reported that Myr47 reduces the cellular uptake of HBV surface antigen (HBsAg, subviral particle of HBV) in the absence of NTCP expression. In this study, we analyzed how Myr47 reduces the cellular uptake of lipid nanoparticles (including liposomes (LPs) and HBsAg) without NTCP expression. By using Myr47 mutants lacking the HBV infection inhibitory activity, they could reduce the cellular uptake of LPs in an N-myristoylation-dependent manner and an amino acid sequence-independent manner, not only in human liver-derived cells but also in human non-liver-derived cells. Moreover, Myr47 and its mutants could reduce the interaction of LPs with apolipoprotein E3 (ApoE3) in an N-myristoylation-dependent manner regardless of their amino acid sequences. From these results, lipopeptides are generally anchored by inserting their myristoyl residue into the lipid bilayer and can inhibit the interaction of LPs/HBsAg with apolipoprotein, thereby reducing the cellular uptake of LPs/HBsAg. Similarly, Myr47 would interact with HBV, inhibiting the uptake of HBV into human hepatic cells, while the inhibitory effect of Myr47 may be secondary to its ability to protect against HBV infection.  相似文献   

10.
HBV属嗜肝DNA病毒科,可引起人类急性和慢性肝炎,甚至肝硬化、肝癌。目前的抗病毒药物因不能彻底清除肝细胞内HBV,故很难达到治愈的效果。近年来,HBV持续感染的机制受到广泛关注,主要涉及宿主与病毒两方面,从病毒方面展开,主要阐述了cccDNA、HBV颗粒和HBV自身组分维持HBV持续感染的相关研究进展。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号