细胞内生成的抗整合酶单链抗体阻断HIV—1复制的实验研究

通通细胞内表达抗ＨＩＶ－１整合酶单链抗体（ＩＮ－ｓＦｖ）基因,阻断病毒基因组与缩主细胞基因组的整合,进而抑制病毒复制,探讨该基因载体在ＮＩＶ－１感染基因治疗中应用的意义。方法用带有ＩＮ－ｓＦｖ基因的逆转录病毒表达载体ｐＳＬＸＣＭＶ／ＩＮｓＦＶ转染ＰＡ３１７包装细胞,并用包装后含有目的基因的逆转录病毒转导ＳｕｐＴ１细胞及外周血单个核细胞（ＰＢＭＣ）。以ＨＩＶ－１ＮＬ４－３病毒株感染表达ＩＮ－ｓＦｖ的     

SDF1基因一个多态位点在中国人群中的分布

关于趋化因子受体与人免疫缺陷病毒（ｈｕｍａｎｉｍｍｕｎｏｄｅｆｉｃｉｅｎｃｙｖｉｒｕｓ，ＨＩＶ）的相关性研究于１９９５年起步，迅速成为当前ＨＩＶ研究热点。１９９６年，Ｏｂｅｒｌｉｎ等［１］和Ｂｌｅｕｌ等［２］发现了基质细胞衍生因子（ｓｔｒｏｍａｌｄｅｒｉｖｅｄｆａｃｔｏｒ１，ＳＤＦ１）作为趋化因子受体ＣＸＣＲ４的配体在ＣＤ＋淋巴细胞和ＨＩＶ１的融合中起作用，它是嗜淋巴细胞ＨＩＶ１株感染的体外潜在抑制因子，可阻断ＨＩＶ１侵入人体的通路。本实验的目的是观察ＳＤＦ１基因多态性在中国不同地区汉族…     

趋化因子受体HIV-1

β－趋化因子受体５（ＣＣＲ５）是近年来新克隆的趋化因子受体超基因家族的一个重要成员之一,由于它的被发现才使人们认识到ＨＩＶ－１ 的感染除了Ｔ 细胞上的ＣＤ４＋ 外还有另一条通过巨噬细胞表面辅助受体ＣＣＲ５ 介导的传播途径。本文就近年来有关趋化因子受体基因家族的组成成员、结构与功能、不同人种的基因型、ＨＩＶ－１ 与细胞表面辅助受体ＣＣＲ５ 的结合,进入机理及阻断ＨＩＶ－１ 感染的可能途径作一详要的综述     

人源抗人免疫缺陷病毒1型噬菌体抗体库的构建及筛选

目的构建人免疫缺陷病毒１型（ＨＩＶ－１）特异性噬菌体抗体库，制备人源抗ＨＩＶ－１ｇｐ１２０单克隆抗体。方法以半巢式聚合酶链反应（ＰＣＲ）从ＨＩＶ－１感染者外周血单个核淋巴细胞中扩增抗体重链Ｆｄ和轻链（ｋ）基因，与噬菌体载体ｐＣｏｍｂ３连接，构建噬菌体抗体Ｆａｂ组合文库。对抗体库进行３轮吸附－洗脱－扩增的亲和选择后，以ＥＬＩＳＡ法筛选抗ＨＩＶ－１ｇｐ１２０噬菌体抗体，并进行ＤＮＡ序列分析和Ｆａｂ的可溶性表达。结果半巢式ＰＣＲ有效地扩增出Ｆｄ和ｋ基因，以此构建成容量为１９５×１０７的噬菌体抗体库。３轮亲和选择使特异性抗体得到高度富集，抗ＨＩＶ－１ｇｐ１２０噬菌体抗体阳性克隆占３２％。对一阳性克隆抗体基因ＣＨ１和ＣＬ部分ＤＮＡ序列进行了测定，并在大肠杆菌表达出可溶性Ｆａｂ。结论抗ＨＩＶ－１特异性噬菌体抗体库的构建和人源抗ＨＩＶ－１ｇｐ１２０单克隆抗体的制备为今后筛选抗ＨＩＶ中和抗体奠定了基础，具有重要的应用价值。     

抗人免疫缺陷病毒1型gp120人源单链抗体的表达

目的研究人源抗人免疫缺陷病毒１型（ＨＩＶ－１）ｇｐ１２０单链抗体（ＳｃＦｖ）。方法以人工合成的ＨＩＶ－ｌｇｐ１２０Ｖ３环多肽为抗原，利用噬菌体抗体库技术，筛选含有抗－ｇｐ１２０ＳｃＦｖ基因的噬菌体，提取质粒，转化大肠杆菌ＨＢ２１５１，表达可溶性ＳｃＦｖ。结果经ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｒｎｂｌｏｔ分析，表达产物分子量为２８ｋＤ左右，且具有ｃ－ｍｙｃ活性；ＥＬＩＳＡ和Ｄｏｔｂｌｏｔ结果表明，可溶性ＳｃＦｖ具有较好的抗原结合活性和较强的特异性；竞争性ＥＬＩＳＡ实验结果进一步证明表达产物的特异抗－ｇｐ１２０活性。结论该技术便捷有效，可大量获得人源抗ＨＩＶ抗体片段，为进一步研究抗ＨＩＶ抗体的生物活性和ＨＩＶ感染诊治打下基础     

人类免疫缺陷病毒包膜糖蛋白V3区对细胞结合能力的研究

目的：研究人类免疫缺陷病毒（ＨＩＶ）不同亲嗜株包膜糖蛋白Ｖ３区结合于靶细胞的能力。方法：合成来源于不同嗜性ＨＩＶ－１Ｖ３区的生物素标记和非标记的多肽。采用流式细胞计数分析生物素化的 Ｖ３多肽对细胞的结合能力以及细胞表面的结合配体。结果：ＨＩＶ－１Ｘ４　亲嗜株ＩＩＩＢＶ３区能结合于多种细胞的表面，包括辅助受体ＣＸＣＲ４；竞争实验结果显示蛋白酶抑制剂能抑制该结合。Ｒ５亲嗜株 ＡＤＡ Ｖ３区只极微弱地结合于外周血单核细胞和表达ＣＣＲ５ 的人星形胶质细胞表面。结论：不同嗜性ＨＩＶ－１Ｖ３区结合于细胞表面的能力不同从亲嗜株Ｖ３区直接结合于细胞表面并被其自身所增强，其靶分子至少包括辅助受体 ＣＸＣＲ４和蛋白酶分子；而Ｒ５亲嗜株 ＡＤＡ Ｖ３区则不结合于 ＣＣＲ５和蛋白酶。     

针对HIV—1进入细胞过程的抑制研究进展

ＨＩＶ１进入宿主细胞的过程可简单归纳为：ＨＩＶ１首先通过其囊膜糖蛋白复合物ｇｐ１２０ｇｐ４１中的ｇｐ１２０与靶细胞上的受体ＣＤ４结合，使得ｇｐ１２０的构象发生改变，并继而与靶细胞上的辅受体ＣＸＣＲ４或ＣＣＲ５结合，结果导致ｇｐ４１的构型改变，暴露出其融合肽并插入到宿主细胞膜，从而启动病毒膜与细胞膜的融合，完成病毒进入宿主细胞的感染过程。１针对ＨＩＶ１ｇｐ１２０与ＣＤ４结合反应的抑制剂１．１可溶性ＣＤ４片段及其衍生物早期研究曾证明重组表达的可溶性ＣＤ４片段对体外培养的ＨＩＶ１具有明显的抑制活性，在…     

硫酸酯化箬叶多糖抗HIV-1机制的初步研究

目的 探讨硫酸脂化箬液多糖（Ｓ－ＩＴＰＳ）抗ＨＩＶ的机制,为进一步开发该药提供理论依据。方法 于病毒接种前,接种同时及接种后分别在培养细胞（ＭＴ－４）中加入硫酸脂化箬叶多糖（Ｓ－ＩＴＰＳ）,在Ｓ－ＩＴＰＳ存在或不存在的条件下培养１￣４周。终点以病毒半数感染量（ＴＣＩＤ５０法）,细胞病变（ＣＰＥ）,ＭＴＴ染色细胞保护率（ＭＴＴ法）及培养上清中的ｐ２４抗原滴度９ＥＬＩＳＡ法）作为评价指标,判断药效,分     

人粒细胞巨噬细胞集落刺激因子在重组痘苗病毒中的 …

目的 观察人ＧＭ－ＣＳＦ（粒细胞－巨噬细胞集落刺激因子）对重组痘苗病毒免疫效果的影响。方法 大鼠体内观察。结果 从核酸和蛋白水平均证实重组痘苗病毒ＲＶＪＳＢ１１７５Ｄ／ＧＭ－ＣＳＦ可同时表达ＧＭ－ＣＳＦ及ＨＳＶ－１ｇＤ（单纯疱疹病毒ｇＤ糖蛋白），但ＲＶＪＳＢ１１７５Ｄ／ＧＭ－ＣＳＦ免疫大鼠产生的抗－ＨＳＶ１ｇＤ特异性抗体水平与ＲＶＪＳＢ１１７５Ｄ组相比无显著性差异。结论 人ＧＭ－ＣＳＦ在大鼠体内对     

HLA多态性与HIV感染及AIDS发病相关性的研究

为研究人类白细胞抗原（ＨＬＡ）和人免疫缺陷病毒（ＨＩＶ）易感性的关系，本文分析比较了以下三组人群的ＨＬＡ表型频率和单倍型频率：①１７２例正常人；②１７例血清ＨＩＶ阴性高危人群；③１８０例血清ＨＩＶ阳性患者，其中２１例发展为艾滋病（ＡＩＤＳ），３７例６个月内ＣＤ４＋淋巴细胞降低至少２０％（ＣＤ４ｄｅｃｌｉｎｅ）。在１７２例对照和１８０例血清ＨＩＶ阳性受试者的比较中发现，其ＨＬＡ表型频率和单倍型频率没有显著差别，提示ＨＩＶ感染与ＨＬＡ无关联。然而，ＨＬＡ－Ｂ２１、ＨＬＡ－Ｂ８、ＨＬＡ－Ｂ３５表型及ＨＬＡ－Ａ１－Ｂ８、ＨＬＡ－Ｂ８－ＤＲ３、ＨＬＡ－Ａ１－Ｂ８－ＤＲ３单倍型与ＣＤ４阳性淋巴细胞下降，或与血清ＨＩＶ感染发展成ＡＩＤＳ病显著相关。１７例ＨＩＶ血清阴性高危人群中，无一携带单倍型ＨＬＡ－Ａ１－Ｂ８－ＤＲ３，提示该单倍型可能与ＨＩＶ感染的抗性相关。     

The influence of CD4 and CXCR4 on maedi-visna virus-induced syncytium formation

CD4 is the principal binding site for human and simian immunodeficiency virus (HIV/SIV) receptor interactions and the a chemokine receptor CXCR4 has been implicated as a primordial lentivirus receptor. This study sought to determine the relevance of CD4 and CXCR4 in virus-receptor interactions for the prototype lentivirus, maedi-visna virus (MVV) of sheep. Neither CD4 nor alpha/beta chemokine receptors represent principal receptors for MVV since human osteosarcoma cells devoid of these molecules were susceptible to productive infection. Interestingly, the presence of either CD4 and/or CXCR4 on indicator cells dramatically enhanced MVV-induced cell fusion (syncytium formation) for three independent virus strains. Syncytium formation results from virus-receptor interactions and can be inhibited by receptor ligands. However, neither SDF-la that binds CXCR4 nor recombinant gp120 (rgp120) that binds CD4 could specifically inhibit the observed enhancement of MVV-induced cell fusion under conditions that significantly reduced HIV-1-induced cell fusion. Our observations suggest that CD4 and CXCR4 may represent optional auxiliary components of an MVV receptor (or receptor complex) that facilitate MVV-mediated membrane fusion events, a feature important for virus entry. This potential accessory role for CXCR4 in MW receptor interactions may reflect the distant relationship between the ovine (MVV) and the human/feline lentiviruses (HIV/FIV).     

Functional HIV CXCR4 coreceptor on human epithelial Langerhans cells and infection by HIV strain X4

HIV can cross the intact epithelium of genital mucosae via Langerhans cells. Fresh Langerhans cells are known to express CD4 and CCR5. The presence of CXCR4 on the surface of cultured but not freshly isolated Langerhans cells has been described. In the present study, we demonstrate that CXCR4 was expressed by fresh Langerhans cells isolated and purified from epidermis. However, the percentage of Langerhans cells expressing CXCR4 or CCR5 increased during maturation of the cells in culture, especially in the presence of exogenous granulocyte-macrophage colony-stimulating factor. To determine whether CXCR4 was functional, freshly isolated Langerhans cells were infected with HIV LAI, a T-cell-tropic strain, and p24 protein production was measured in culture supernatants. p24 production was observed when infected Langerhans cells were cocultured with SupT1 cells. However, the presence of HIV provirus DNA was evidenced within the infected Langerhans cells by nested PCR. Ultrastructural studies confirmed the formation of syncytia when Langerhans cells were cocultured with SupT1 cells. Preincubation of Langerhans cells with azidothymidine or SDF-1-alpha, a natural ligand for CXCR4, prevented infection. These data demonstrated that CXCR4 is present on the surface of Langerhans cells freshly isolated from human skin epidermis and that this expression is functional.     

CD4+ NK cells can be productively infected with HIV, leading to downregulation of CD4 expression and changes in function

NK cells mediate the innate immune response, and HIV-infected individuals demonstrate altered NK cell phenotype and function. We find that CD4+ NK cells are susceptible to HIV infection; this could account for the NK cell dysfunction seen in HIV-infected individuals. CD4+ NK cells express CXCR4 and can be infected with X4-tropic viruses and some primary R5-utilizing viral isolates. Treatment with the CXCR4 ligands AMD3100 and SDF-1α partially blocks infection with X4-tropic virus, treatment with anti-CCL Igs upregulates CCR5 surface expression and enables infection with HIV-Bal. HIV infection of NK cells results in CD4 downregulation and the production of infectious virus. HIV-infected CD4+ NK cells mediate NK cell cytotoxicity, however, HIV infection is associated with decreased chemotaxis towards IL-16. Thus, HIV infection of CD4+ NK cells could account for the NK cell dysfunction observed in HIV-infected individuals. Furthermore infected NK cells could serve as a viral reservoir of HIV in vivo.     

Downregulation of CCR5 on activated CD4 T cells in HIV-infected Indians

BACKGROUND: HIV infection in India is unique as it occurs predominantly by CCR5-utilizing isolates that exhibit no co-receptor switch. OBJECTIVES: To study HIV-1 co-receptor dynamics on T cells and monocytes following viral infection. STUDY DESIGN: HIV co-receptor expression was evaluated by flow cytometry on various cell subsets in HIV-infected Indians and in vitro in human peripheral blood mononuclear cells infected with CCR5- or CXCR4-utilizing HIV-1. Transfection of the T cell line CEM-CCR5 (which expresses CD4, CCR5 and CXCR4) with HIV-1 Nef or Vpu expression vectors, or treatment with recombinant soluble gp120 from CCR5- and CXCR4-tropic HIV-1, was carried out to determine their effects on co-receptor expression. RESULTS: Indian HIV patients had fewer CD4(+)CCR5(+) T cells and CCR5-expressing activated CD4(+) T cells, but higher CXCR4-expressing activated CD4(+) T cells compared with controls. Expression of CCR5 was not different on monocytes in HIV patients as compared to controls. The CCR5 downregulation on T cells was HIV infection specific and was governed by the co-receptor-utilization phenotype of the virus. The Nef and soluble gp120 proteins induced CCR5 downregulation, the latter in a co-receptor-utilization phenotype specific manner. CONCLUSIONS: The HIV-1 co-receptor dynamics in Indian patients is distinct from western patients and depends upon the virus surface protein. We propose this to be a viral survival strategy.     

Raft localization of CXCR4 is primarily required for X4-tropic human immunodeficiency virus type 1 infection

Human immunodeficiency virus type 1 (HIV-1) infection is initiated by successive interactions of viral envelope glycoprotein gp120 with two cellular surface proteins, CD4 and chemokine receptor. The two most common chemokine receptors that allow HIV-1 entry are the CCR5 and CXCR4. The CD4 and CCR5 are mainly localized to the particular plasma membrane microdomains, termed raft, which is rich in glycolipids and cholesterol. However, the CXCR4 is localized only partially to the raft region. Although the raft domain is suggested to participate in HIV-1 infection, its role in entry of CXCR4-tropic (X4-tropic) virus is still unclear. Here, we used a combination of CD4-independent infection system and cholesterol-depletion-inducing reagent, methyl-β-cyclodextrin (MβCD), to address the requirement of raft domain in the X4-tropic virus infection. Treatment of CD4-negative, CXCR4-positive human cells with MβCD inhibited CD4-independent infection of the X4-tropic strains. This inhibitory effect of the cholesterol depletion was observed even when the CXCR4 was over-expressed on the target cells. Soluble CD4-induced infection was also inhibited by MβCD. The MβCD had no effect on the levels of cell surface expression of CXCR4. In contrast to these infections, MβCD treatment did not inhibit CD4-dependent HIV-1 infection in the wild type CD4-expressing cells. This study and previous reports showing that CD4 mutants localized to non-raft domains function as HIV-1 receptor indicate that CXCR4 clustering in the raft microdomains, rather than CD4, is the key step for the HIV-1 entry.     

Mouse serum factor(s) down-modulate the CD4 and CXCR4 molecules on human T cells conferring resistance to HIV infection in NOG mice

Human cells have developed innate immunity, exploiting several means to block virus infection, and viruses have evolved diverse strategies to resist these. We show here that the human immunodeficiency virus 1 (HIV-1) could neither progressively infect engrafted human leukemic T cells nor repress their growth in NOG mice. However, ED-40515(–) cells infected with HIV-1 before inoculation were found to significantly delay the onset of tumor growth and increased the survival period of NOG mice. ED-40515(–) tumor cells showed resistance to HIV-1 which was apparently correlated with the down-regulation of CD4 and CXCR4 molecules in NOG mice. Serum from three different mouse strains, including NOG, retained a suppressive effect on the CD4 molecule of ED-40515(–) cells in vitro. ED-40515(–) cells obtained from mice re-expressed CD4 and CXCR4 molecules upon in vitro culture and were again successfully infected with HIV-1. These findings indicate that HIV-1 may initially successfully delay or regress tumor growth in NOG mice, but eventually fails to do so because of the evolution of HIV-resistant cells due to a rapid down-modulation of CD4 and CXCR4. Our data also demonstrated that some unknown soluble factor(s) present in mouse serum was responsible for conferring resistance to HIV infection to human T cells.Grant sponsor: supported by grants from the Ministry of Education, Science and Culture and Ministry of Health, Labor and Welfare of Japan.     

Selective HIV-1-induced downmodulation of CD4 and coreceptors

Summary.  CD4 and members of the chemokine receptor family are required for infection of host cells, in vitro and in vivo, by the human immunodeficiency virus type-1. Although it is established that HIV-1 gp120 interacts with CD4 and the coreceptors CCR5 or CXCR4 at the plasma membrane during HIV entry, longer-term interactions taking place between these molecules and HIV Env are less well understood. We have measured the cell surface expression of CD4, CCR5 and CXCR4 on a CD4⁺/CXCR4⁺CCR5⁺ T cell line following infection by cell line-adapted X4 and primary X4, X4R5 and R5 viruses. We report a selective downmodulation of CD4 by X4 and R5X4 viruses, but not by R5 viruses. None of the viruses tested significantly reduced CXCR4 expression at any time after infection. CCR5 protein and mRNA expression was eliminated by chronic infection with R5 viruses. These results indicate that chronic HIV-1 infection has distinct effects on CD4 and coreceptor membrane expression that depends on viral origin and coreceptor usage. Accepted October 25, 1999     

Epitope mapping and characterization of a novel CD4-induced human monoclonal antibody capable of neutralizing primary HIV-1 strains

Human immunodeficiency virus (HIV-1) enters target cells by binding its gp120 exterior envelope glycoprotein to CD4 and one of the chemokine receptors, CCR5 or CXCR4. CD4-induced (CD4i) antibodies bind gp120 more efficiently after CD4 binding and block the interaction with the chemokine receptor. Examples of CD4i antibodies are limited, and the prototypes of the CD4i antibodies exhibit only weak neutralizing activity against primary, clinical HIV-1 isolates. Here we report the identification of a novel antibody, E51, that exhibits CD4-induced binding to gp120 and neutralizes primary HIV-1 more efficiently than the prototypic CD4i antibodies. The E51 antibody blocks the interaction of gp120-CD4 complexes with CCR5 and binds to a highly conserved, basic gp120 element composed of the beta 19-strand and surrounding structures. Thus, on primary HIV-1 isolates, this gp120 region, which has been previously implicated in chemokine receptor binding, is accessible to a subset of CD4i antibodies.     

早、中、晚孕期胎盘因子对人外周血淋巴细胞CD4、CCR5和CXCR4表达的影响

目的 通过研究早、中、晚孕期胎盘因子(PF)对人外周血淋巴细胞(PBLs)中CD4、CCR5和CXCR4表达的作用,探讨PF在人免疫缺陷病毒-1(HIV-1)垂直传播中的作用及其机理.方法 制备早、中、晚孕期PF.分离人外周血单个核细胞,并分别与相对浓度为25%的早、中、晚孕期PF作用,培养24 h后收集细胞,荧光抗体标记,流式细胞术检测外周血淋巴细胞(PBLs)中CD4、CCR5和CXCR4表达,以及CD4 T细胞中CCR5 细胞、CXCR4 细胞、CCR5 CXCR4 细胞所占的百分率.结果 各孕期PF均可显著降低PBLs中CCR5的表达,其中早孕期PF的作用明显强于中、晚孕期PF的作用;各孕期PF组CD4 T细胞中CCR5 细胞的百分率均显著低于对照组,早孕期PF组CD4 T细胞中CCR5 细胞的百分率明显低于中、晚孕期PF组;各孕期PF组CD4 T细胞中CCR5 CXCR4 细胞的百分率均显著低于对照组,早孕期PF组CD4 T细胞中CCR5 CXCR4 细胞的百分率显著低于晚孕期PF组.结论 各孕期PF均可显著降低PBLs中CCR5的表达,以及CD4 T细胞中CCR5 细胞和CCR5 CXCR4 细胞的百分率,早孕期PF作用最强,中、晚孕期PF效应相当,PF可能通过抑制R5病毒的人胞而具有抗R5病毒的作用,并可能在阻断HIV-1宫内感染中具有重要作用.