排序方式: 共有36条查询结果,搜索用时 15 毫秒
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Zhou T Xu L Dey B Hessell AJ Van Ryk D Xiang SH Yang X Zhang MY Zwick MB Arthos J Burton DR Dimitrov DS Sodroski J Wyatt R Nabel GJ Kwong PD 《Nature》2007,445(7129):732-737
The remarkable diversity, glycosylation and conformational flexibility of the human immunodeficiency virus type 1 (HIV-1) envelope (Env), including substantial rearrangement of the gp120 glycoprotein upon binding the CD4 receptor, allow it to evade antibody-mediated neutralization. Despite this complexity, the HIV-1 Env must retain conserved determinants that mediate CD4 binding. To evaluate how these determinants might provide opportunities for antibody recognition, we created variants of gp120 stabilized in the CD4-bound state, assessed binding of CD4 and of receptor-binding-site antibodies, and determined the structure at 2.3 A resolution of the broadly neutralizing antibody b12 in complex with gp120. b12 binds to a conformationally invariant surface that overlaps a distinct subset of the CD4-binding site. This surface is involved in the metastable attachment of CD4, before the gp120 rearrangement required for stable engagement. A site of vulnerability, related to a functional requirement for efficient association with CD4, can therefore be targeted by antibody to neutralize HIV-1. 相似文献
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Earl PL Americo JL Wyatt LS Eller LA Whitbeck JC Cohen GH Eisenberg RJ Hartmann CJ Jackson DL Kulesh DA Martinez MJ Miller DM Mucker EM Shamblin JD Zwiers SH Huggins JW Jahrling PB Moss B 《Nature》2004,428(6979):182-185
The potential use of smallpox as a biological weapon has led to the production and stockpiling of smallpox vaccine and the immunization of some healthcare workers. Another public health goal is the licensing of a safer vaccine that could benefit the millions of people advised not to take the current one because they or their contacts have increased susceptibility to severe vaccine side effects. As vaccines can no longer be tested for their ability to prevent smallpox, licensing will necessarily include comparative immunogenicity and protection studies in non-human primates. Here we compare the highly attenuated modified vaccinia virus Ankara (MVA) with the licensed Dryvax vaccine in a monkey model. After two doses of MVA or one dose of MVA followed by Dryvax, antibody binding and neutralizing titres and T-cell responses were equivalent or higher than those induced by Dryvax alone. After challenge with monkeypox virus, unimmunized animals developed more than 500 pustular skin lesions and became gravely ill or died, whereas vaccinated animals were healthy and asymptomatic, except for a small number of transient skin lesions in animals immunized only with MVA. 相似文献
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The objectives of this study were to compare vegetative and reproductive growth characters of bitterbrush ( Purshia tridentata Pursh) stands as they relate to browsing levels. Growth characters were measured on 10 ecologically diverse stands in southwestern Montana on which browsing ranged from 0% to 60% of all current annual long shoot (LS) growth. Bitterbrush plants exhibited both twig-level and plant-level responses to browsing. Total bud density per plant was similar for browsed and unbrowsed sites, but differed ( P P P P P < 0.05). Our data suggest that long-term unbrowsed plants should not be used as a standard for comparison with normally browsed plants. 相似文献
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本通过对几种拆分手性药物的方法的列举,比较几种方法,详细介绍了几种方法的特点,以及它们的不同作用。各个方法中又列出了不同的线索,根据这些线索来研究这几种拆分的方法,它们的优缺点以及针对这些缺点的解决方法,最后给出了几个典型的用该方法的实验,以辨别它们的效用。 相似文献