酿酒酵母表达的人类免疫缺陷症病毒包膜多肽不同区段的抗原性和免疫原性

人类免疫缺陷症病毒(HIV)SF2株的包膜(env)基因已预测出来。其感染细胞中160千道尔顿(KDa)糖蛋白(gp160)为env糖蛋白的前体,其氨基末端为gp120,羧基末端为gp41。gp120介导HIV与易感的辅助/诱导T细胞表面的病毒受体T4抗原结合。作者用基因工程方法在酵母中表达了HIV-SF2 env基因的不同区段,并研究其多肽的免疫原性。     

席氏丰岑变种中能结合HIV gp41的酚类化合物

HIV 包膜蛋白由表面糖蛋白 gp120和跨膜糖蛋白 gp41组成,它在病毒与细胞融合和病毒进入宿主细胞过程中起重要作用。gp120与靶细胞受体的相互作用引起 gp41构象改变,导致少部分 gp41穿过细胞膜引起 HIV与细胞融合;在构象改变时,gp41的卷曲螺旋区域就会暴露出来,因此,能够有力结合该     

病毒样颗粒以及基于DNA的候选艾滋病疫苗

体液免疫和细胞免疫应答对于控制人类免疫缺陷病毒 ( HIV)的感染和复制是至关重要的。因此 ,作者利用杆状病毒表达系统建立了含有高水平 Env蛋白的 HIV和猴免疫缺陷病毒 ( SIV)病毒样颗粒 ( VLP)生产系统。这些截短的 Env蛋白能被高效地裂解为gp1 2 0和 gp4 1。可溶性 CD4分子 ( s CD4 )与VLP以 1∶ 1 0的比例结合 ,而且 VL P与s CD的结合呈 Env蛋白依赖性。另外 ,HIV的 Env能有效地转运到细胞表面导致细胞融合。进一步研究发现含有来源于嗜 T细胞病毒 ( BH1 0 ) Env蛋白的 VL P是利用 CX-CR4诱导细胞凋亡 ,而含有来源于双…     

重组可溶性CD4分子体外可阻断HIV感染

T细胞表面糖蛋白CD4(T4)是人体免疫缺陷病毒Ⅰ型(HIV-1)的细胞受体.HIV-1为引起获得性免疫缺陷综合征(艾滋病)的病毒之一.通过CD4和病毒外壳糖蛋白(gp 102)的复合免疫沉降作用以及利用重组gp102为结合探针进行的实验,表明CD4对HIV的识别可能受制于gp102.从仓鼠稳定卵巢传代细胞群的培养液中纯化得到的重组可溶性CD4分子,对病毒分子的复制和病毒诱导的细胞损伤均有很强的抑制     

作用于HIV gp120的进入抑制剂研究进展

HIV-1病毒为包膜病毒,其感染靶细胞的第一步是由HIV包膜蛋白表面亚基gp120与靶细胞上的CD4分子和辅助受体（趋化因子受体CCR5或CXCR4等）结合,导致gp41的构型发生改变,启动病毒包膜与靶细胞膜的融合。与gp120相结合的一些抗体、蛋白、多糖、多肽和小分子化合物,都可能影响HIV-1病毒包膜和靶细胞膜融合的过程,从而起到抗HIV-1病毒的作用。该文对近年来以HIV gp120为靶点的HIV进入抑制剂的研究进展进行综述。     

应用HIV抗体初筛检测3000例患者临床分析

自 198 1年美国首次报告艾滋病 (AIDS)以来 ,我国近年来AIDS流行已进入快速增长阶段 ,静脉注射毒品为人类免疫缺陷病毒 (HIV)感染的主要途径外 ,性接触传播、输注HIV感染供血血源也是不容忽视的传播途径。为加强HIV感染者的检测 ,我们应用HIV抗体初筛检测 30 0 0患者 ,兹将结果报道与分析如下。对象与方法一、对象本院普通门诊、性病门诊及住院患者血清 30 0 0份 ,其中男 890例、女 2 110例 ,男女之比 0 4 2∶1,年龄 4～ 72岁 ,平均年龄 35 5岁。初筛临床标准 :( 1)发热 1个月以上 ;( 2 )近期 ( 3～ 6个月 )体重下降 10 %以上 ;(…     

NCI研制有效的抗HIV抗体

到目前为止 ,病毒进入是人类免疫缺陷病毒 (HIV)研究界重点研究的课题 ,因此针对病毒进入细胞时的疾病阶段的生物技术的问世仅是时间问题。最近美国国立癌症研究所 (NCI)报道了一种抗体疗法 ,它能有效抗各型 HIV及其亚型。　　此抗体 (其实为抗体片段或 Fab)称为 X5 ,其有效的原因是它能针对 HIV高度保守的细胞靶向机理。为了感染细胞 ,病毒形成一种由包膜蛋白 (Env) gp12 0表位及细胞 CD4和 CCR5受体组成的复合体。当这 3种组分结合时 ,Env发生构象变化 ,并进入能与 X5结合的过渡状态 (这种状态在所有 HIV株中均高度保守 )。体外…     

HIV蛋白酶抑制剂与细胞凋亡

HIV感染人体后造成大量CD4 + T淋巴细胞的凋亡 ,从而破坏免疫系统 ,使机体无法抵抗病毒的入侵 ,导致免疫缺陷。目前的药物靶点都针对病毒本身 ,无法清除体内储存病毒的感染细胞 ,而HIV蛋白酶抑制剂治疗HIV/AIDS患者后可以减少HIV感染引起的细胞凋亡 ,帮助机体恢复免疫功能 ,并且这种作用与其抑制病毒的作用是相独立的 ,这提示了可以通过免疫重建的策略来治疗AIDS。本文综述了HIV蛋白酶抑制剂的研究和发展概况 ,其作用特点以及对细胞凋亡的影响。明确HIV蛋白酶抑制剂与细胞凋亡的关系 ,可以启发新的思路从细胞着手 ,通过恢复机体的免疫能力来对抗病毒 ,从根本上治疗AIDS。     

AMD3100在造血干/祖细胞动员中的作用机制及应用进展

20多年前，人们发现了一种polyoxometalate能降低人类获得性免疫缺陷综合征（AIDS）患者体内的人类免疫缺陷病毒（HIV）病毒水平^[1]，并逐渐研究出与之结构相似、安全有效的AMD3100，并发现它能特异性拮抗CXCR4，阻断后者参与的生理过程。由此，人们发现了AMD3100介入了造血干/祖细胞动员、HIV病毒进入T细胞、炎症、类风湿关节炎、哮喘和血管损伤等方面的作用。     

贵州省HIV/AIDS患者合并梅毒感染病毒载量与T淋巴细胞亚群相关性分析

目的 分析贵州省近3年人类免疫缺陷病毒(HIV)/艾滋病(AIDS)患者合并梅毒感染病毒(HIV-RNA)载量与T淋巴细胞亚群之间的相关性。方法 选取2019年1月1日—2021年12月31日在贵阳市公共卫生救治中心新确诊且未进行抗逆转录病毒治疗(ART)的HIV/AIDS患者2 869例。根据患者梅毒检测结果,分为单纯HIV感染组2 289例、HIV/梅毒现症感染组333例和HIV/梅毒既往感染组247例。比较3组患者一般人口学资料及实验室检测指标基线数据的差异,并分析HIV不同组间各自HIV-RNA载量与T淋巴细胞亚群的相关性。结果 HIV/梅毒现症感染组的年龄小于单纯HIV感染组和HIV/梅毒既往感染组,男性占比高于单纯HIV感染组和HIV/梅毒既往感染组(P<0.05)。HIV/梅毒现症感染组的HIV-RNA载量低于单纯HIV感染组,CD4⁺T细胞、CD8⁺T细胞、CD3⁺T细胞均高于单纯HIV感染组(P<0.05);HIV/梅毒既往感染组的HIV-RNA载量高于HIV/梅毒现症感染组,CD4     

Inhibitors of the entry of HIV into host cells

The development of mechanistic insight into the process by which HIV enters host cells has revealed a panoply of targets that offer considerable potential as sites for pharmacological intervention. The gp120/gp41 protein complex, expressed on the virion surface, mediates HIV entry by a process initiated by the engagement of the host cell receptor CD4. Subtle conformational changes triggered by this interaction expose elements of gp120 to the seven-transmembrane, G protein-coupled chemokine receptors CCR5 or CXCR4 expressed on host cells, a contact that relieves constraints imposed on gp41 by gp120. This leads to a major conformational rearrangement of gp41, which results in the insertion of the fusion peptide into the host cell membrane and the assembly of the amino terminus heptad repeat into a trimeric form that is subsequently recognized by the carboxy terminal heptad repeat. The latter process leads to juxtaposition of the viral and host cell membranes, a prelude to fusion. The most prominent strategies and targets that are actively being exploited as drug discovery opportunities are inhibition of the attachment of HIV to host cells, blockade of chemokine receptors and interference with the function of gp41. Inhibitors of each of these steps in the HIV entry process with potential clinical relevance are reviewed in the context of their status in the drug development process. The most significant entity to emerge from this area of research to date is enfuvirtide, a 36-amino acid derivative that interferes with the function of gp41. Enfuvirtide is the first HIV entry inhibitor to be granted a license for marketing (it was approved in the US and Europe in March 2003), and its introduction portends the beginning of what promises to be an exciting new era of HIV therapy.     

A post-CD4-binding step involving interaction of the V3 region of viral gp120 with host cell surface glycosphingolipids is common to entry and infection by diverse HIV-1 strains

The V3-loop region in the envelope protein gp120 of HIV is critical for viral infection, but its interaction with the target cells is not clear. Using synthetic peptides, representing linear V3 sequences as reagents, we obtained evidence to show inhibition of infection by both T-cell- and macrophage-tropic strains of human immunodeficiency virus type 1 (HIV-1) (X4 and R5, respectively), without interfering with gp120-CD4 interaction, by the V3 peptides through binding to host cell membrane glycosphingolipids (GSL). Synthetic peptides mimicking the central 15-21 amino acid sequence of the V3-loop region in both X4 and R5 strains of HIV-1 competed with and blocked the entry of both types of HIV isolates. These HIV-inhibitory V3 peptides exhibited specific binding to target cells that was not competed by antibodies to either the primary receptor CD4 or the co-receptors CXCR-4 and CCR5. However, R15K, the V3 peptide from HIV-1 IIIB gp120 exhibited specific binding to three distinct cell surface GSL: GM3, Gb3, and GalCer. Further, R15K inhibited GSL binding of gp120 from both HIV-1 IIIB (X4, Gb3-binding strain) and HIV-1 89.6 (X4R5, GM3-binding strain). Together, these results suggest a critical V3-mediated post-CD4-binding event involving cell surface GSL binding represented by the HIV-inhibitory V3 peptides, that is common for the entry of diverse HIV-1 strains and may be targeted for the development of novel HIV therapeutics aimed at blocking viral entry.     

Cell cycle dysregulation during HIV infection: perspectives of a target based therapy

Human immunodeficiency virus (HIV) infection is characterized by a severe depletion of both CD4+ and CD8+ T cells, representing the result of virus-mediated killing of infected lymphocytes and the programmed cell death (apoptosis) of the uninfected bystander cells. Since only a small fraction of T lymphocytes are depleted by viral killing, apoptosis represents one of the most important mechanism of T cell death during HIV infection. Several apoptotic pathways can be triggered by the different stimuli: persistent T lymphocyte activation; altered death receptor (Fas, TNF-R, TRAIL R1-R2) membrane expression; viral proteins as well as gp120, Tat, and Nef; host factors such as the unbalance of cytokine synthesis by lymphocyte. Nevertheless, new evidences have demonstrated that the persistent HIV induced T cell activation and proliferation cause a cell cycle dysregulation resulting in a 5-fold increase in apoptotic cells. This perturbation represents a link between HIV infection, T cell activation, accelerated cell turnover and increased apoptosis and may thus represent a new therapeutic target. In fact, Interleukin-2 administration reverts such a cell cycle dysregulation and reduces activation induced T cell apoptosis. Herein we analyze the main HIV-related mechanisms of host cell death, that are dysregulation of the cell cycle and apoptosis induction of T lymphocytes. Finally, the role of cytokines at the site of infection and their association with apoptosis will be discussed to get insights into the immunological perturbations accounting for an accelerated disease progression. Current therapeutic approaches and strategies, like HAART and recombinant cytokines, that may, successfully, improve the immune-system dysregulation, are also discussed.     

Cyanovirin-N binds to the viral surface glycoprotein,GP1,2 and inhibits infectivity of Ebola virus

Ebola virus (Ebo) causes severe hemorrhagic fever and high mortality in humans. There are currently no effective therapies. Here, we have explored potential anti-Ebo activity of the human immunodeficiency virus (HIV)-inactivating protein cyanovirin-N (CV-N). CV-N is known to potently inhibit the infectivity of a broad spectrum of HIV strains at the level of viral entry. This involves CV-N binding to N-linked high-mannose oligossacharides on the viral glycoprotein gp120. The Ebola envelope contains somewhat similar oligosaccharide constituents, suggesting possible susceptibility to inhibition by CV-N. Our initial results revealed that CV-N had both in vitro and in vivo antiviral activity against the Zaire strain of the Ebola virus (Ebo-Z). Addition of CV-N to the cell culture medium at the time of Ebo-Z infection inhibited the development of viral cytopathic effects (CPEs). CV-N also delayed the death of Ebo-Z-infected mice, both when given as a series of daily subcutaneous injections and when the virus was incubated ex vivo together with CV-N before inoculation into the mice. Furthermore, similar to earlier results with HIV gp120, CV-N bound with considerable affinity to the Ebola surface envelope glycoprotein, GP(1,2). Competition experiments with free oligosaccharides were consistent with the view that carbohydrate-mediated CV-N/GP(1,2) interactions involve oligosaccharides residing on the Ebola viral envelope. Overall, these studies broaden the range of viruses known to be inhibited by CV-N, and further implicate carbohydrate moieties on viral surface proteins as common viral molecular targets for this novel protein.     

Simian immunodeficiency virus is susceptible to inhibition by carbohydrate-binding agents in a manner similar to that of HIV: implications for further preclinical drug development

Carbohydrate-binding agents (CBAs), such as the plant lectins Hippeastrum hybrid agglutinin (HHA) and Urtica dioica agglutinin (UDA), but also the nonpeptidic antibiotic pradimicin A (PRM-A), inhibit entry of HIV into its target cells by binding to the glycans of gp120. Given the high sequence identity and similarity between the envelope gp120 glycoproteins of HIV and simian immunodeficiency virus (SIV), the inhibitory activity of a variety of CBAs were evaluated against HIV-1, HIV-2, and SIV. There seemed to be a close correlation for the inhibitory potential of CBAs against HIV-1, HIV-2, and SIV replication in cell culture and syncytia formation in cocultures of persistently SIV-infected HUT-78 cell cultures and uninfected CEM cells. CBAs also inhibit transmission of the SIV to T lymphocytes after capture of the virus by dendritic cell-specific ICAM3-grabbing nonintegrin (DC-SIGN)-expressing cells. A total of 8 different SIV strains were isolated after prolonged HHA, UDA, and PRM-A exposure in virus-infected cell cultures. Each virus isolate consistently contained at least 2 or 3 glycan deletions in its gp120 envelope and showed decreased sensitivity to the CBAs and cross-resistance toward all CBAs. Our data revealed that CBAs afford SIV and HIV-1 inhibition in a similar manner regarding prevention of virus infection, DC-SIGN-directed virus capture-related transmission, and selection of drug-resistant mutant virus strains. Therefore, SIV(mac251)-infected monkeys might represent a relevant animal model to study the efficacy of CBAs in vivo.     

Apoptosis and HIV infection: about molecules and genes

During the evolution, the immune system has developed several strategies to fight viral infections. Apoptosis, autophagy and necrosis are different types of cell death that play a main role in the interactions between infective agents and the host, since they are often important defence mechanisms that have to avoid the spreading of the infection. In turn, viruses have evolved numerous ways to evade the host immune system by influencing the behaviour and functionality of several components. HIV infects and kills CD4+ T helper lymphocytes, preferentially those that are antigen-specific, but also encodes proteins with apoptotic capacities, including gp120, gp160, Tat, Nef, Vpr, Vpu, Vif and, last but not least, the viral protease. This latter protein can kill infected and uninfected lymphocytes through the action of several host molecules, mainly members of the tumor necrosis factor family, or via the mitochondrial apoptotic pathway. The proinflammatory state that is characteristic of both the acute and chronic phase of HIV infection facilitates cell death, and is an additional cause of immune damage. Potent antiretroviral drugs that are largely use in therapy can reduce apoptosis by different mechanisms, that not only include the diminished production of the virus by infected cells and the subsequent reduction of inflammation, but also a direct action on the viral protease. The role of the host genetic background is finally crucial in understanding the process of cell death in HIV infection.     

A simple screening system for anti-HIV drugs: syncytium formation assay using T-cell line tropic and macrophage tropic HIV env expressing cell lines--establishment and validation.

The first step in cellular entry of HIV involves binding of the viral envelope glycoprotein complex (gp120/gp41) to specific receptor molecules on the target cells. The cell-cell fusion (syncytium formation) between env expressing cells and CD4+ cells mimics the viral infection of the host cells. To search for anti-HIV substances preventing this process, we constructed the recombinant cell lines, HeLa/CD4/Lac-Z and HeLa/T-env/Tat for T-cell tropic (HIV-1(NL4-3)) system, and HOS/CD4/CCR5/Lac-Z and HeLa/M-env/Tat for macrophage tropic (HIV-1(SF162)) system. When each pair of cells were co-incubated for 20 hours, the multinuclear giant cells (syncytia) were formed and beta-galactosidase was expressed. These systems are less biohazardous because no infectious virus particles are used. Their validity in screening for anti-HIV substances which inhibit syncytium formation was confirmed using various known HIV entry inhibitors.