Prophylactic and therapeutic efficacy of human monoclonal antibodies against H5N1 influenza.
Prophylactic and therapeutic efficacy of human monoclonal antibodies against H5N1 influenza.
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DOI：
10.1371/journal.pmed.0040178
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发表时间：
2007-05
期刊：
影响因子：
3.1
通讯作者：
Suguitan, A. L.
中科院分区：
文献类型：
--
作者：
Simmons, C. P.;Bernasconi, N. L.;Suguitan, A. L.
需要新的预防和治疗战略，以防治人类感染高致病性禽流感H5N1病毒。我们产生了中和性抗h5n1人单克隆抗体（mab），并在小鼠感染模型中测试了它们的预防和治疗效果。我们使用Epstein-Barr病毒使感染高致病性H5N1病毒后康复的越南成年人的记忆B细胞永生。用病毒中和试验筛选B细胞系上清液。克隆了分泌中和抗体的B细胞系，纯化了单克隆抗体。通过体外中和试验检测了这些抗体对不同H5N1毒株的交叉反应性，并在小鼠体内检测了它们的预防和治疗作用。在体外，fl3.14和FLD20.19单克隆抗体均能中和I和II进化枝病毒，而fl5.10和FLD21.140单克隆抗体仅能中和I进化枝病毒。在体内，FLA3.14和FLA5.10以剂量依赖的方式保护A/Vietnam/1203/04 （H5N1）攻毒小鼠免于死亡。单抗预防提供了统计学上显著的肺病毒滴度降低，减少了肺部相关炎症，并限制了病毒的肺外传播。治疗剂量的fl3.14、fl5.10、FLD20.19和FLD21.140至少在感染A/Vietnam/1203/04 （H5N1）后72小时内具有强大的保护作用。单克隆抗体fl3.14、FLD21.140和FLD20.19在体内也具有治疗活性，而非fl5.10。这些研究证明了一个概念，即具有中和活性的全人单克隆抗体可以从恢复期患者的外周血中迅速产生，并且这些单克隆抗体在小鼠模型中对预防和治疗H5N1感染有效。一组中和的、交叉反应的单克隆抗体可能对预防或辅助治疗H5N1流感人间病例有用。Cameron Simmons及其同事在小鼠模型中证明，具有中和活性的人单克隆抗体可以从恢复期患者的外周血中迅速产生，并有效地预防和治疗H5N1感染。每年，数百万人感染流感，这是一种鼻子、喉咙和呼吸道的病毒性疾病。虽然大多数人会康复，但流感爆发（流行病）每年造成约50万人死亡。流感流行的发生是因为免疫系统对病毒蛋白（抗原）做出反应的微小但频繁的变化，这意味着一年产生的免疫反应只能在明年提供部分预防流感的保护。人类流感病毒偶尔也会出现主要的抗原变化。人们对这些病毒（通常起源于动物或鸟类）几乎没有免疫力，所以这些病毒可以引发致命的大流行——全球流行病。1918/9年的西班牙流感、1957年的亚洲流感和1968年的香港流感都导致数百万人死亡。专家认为，另一场大流行早该到来，可能是由H5N1禽流感病毒引发的。H5N1这个名字表明，这种禽流感病毒携带5型血凝素和1型神经氨酸酶，这是两种主要的流感抗原。H5N1能迅速杀死受感染的禽类，目前在世界各地的禽类中存在，自1997年以来，它已造成258例人类流感病例和153例死亡。人们通过与受感染的禽类密切接触而感染H5N1，但幸运的是，H5N1很少在人与人之间传播。H5N1可能随时获得在人与人之间传播的能力并引发人类流感大流行。一些H5N1病毒对用于治疗流感的抗病毒药物具有耐药性，并且在人类大流行H5N1毒株的出现和有效对抗它的疫苗的批量生产之间不可避免地会有几个月的滞后。因此，需要新的预防和治疗策略来对抗人感染H5N1。一种可能是被动免疫疗法，即用能够阻止H5N1感染细胞的抗体（即所谓的中和抗体）对患者进行治疗。在这项研究中，这组科学家产生了中和性人类单克隆抗体（实验室生产的含有一种人类抗体的制剂），并测试了它们在感染H5N1的小鼠中阻止病毒生长的能力。感染H5N1病毒后存活下来的患者会产生中和抗体，因此研究人员从患者的血液中分离出产生这些抗体的免疫细胞并使其永生。他们分别培养每个细胞，并纯化细胞产生的抗体。然后在实验室中测试了这些单克隆抗体对H5N1和其他流感病毒的中和能力。研究人员确定了几种能够中和患者最初感染的H5N1毒株的病毒，并选择了两种进行进一步研究。在试管中，这四种抗体中和了密切相关的H5N1病毒和一种来自不同谱系（进化支）的H5N1病毒，除了最初的H5N1病毒外，这种病毒也引起人类疾病，尽管效力不同。在小鼠身上，在感染前一天或感染后一到三天给予这种抗体，可以保护小鼠免受原始病毒的感染。三种抗体也在一定程度上保护小鼠免受来自不同分支的H5N1病毒的侵害。最后，研究人员表明，抗体通过限制病毒复制、减少病毒在肺部的有害影响和阻止病毒从肺部扩散来保护小鼠。这些结果表明，如果（或当）禽流感开始在人间流行，用人单克隆抗体进行被动免疫治疗可以帮助抗击H5N1禽流感。被动免疫疗法已经被用于预防其他几种病毒的感染。此外，在西班牙流感大流行期间，这种方法的一种原始形式——用恢复期患者的血浆（血液的液体部分）对患者进行早期治疗——使死亡率降低了一半。大量的纯单克隆抗体可以相对容易地制备用于临床，并且本研究表明一些单克隆抗体可以中和来自不同进化支的H5N1病毒。然而，研究人员发出了警告：在被动免疫疗法能够帮助阻止H5N1大流行之前，他们警告说，必须对单克隆抗体进行测试，看它们是否不仅可以中和所有目前传播的H5N1病毒，还可以中和任何可能在抗原性上不同的新出现的大流行病毒。请通过本摘要的在线版本http://dx.doi.org/10.1371/journal.pmed.0040178访问这些网站。美国疾病控制和预防中心为患者和专业人员提供的流感信息，包括禽流感的主要事实美国国家过敏和传染病研究所季节性、禽流感和大流行性流感专题报道世界卫生组织流感概况和禽流感信息，包括人类确诊病例的最新数字英国卫生保护局季节性、禽流感、以及关于被动免疫和单克隆抗体的大流行性流感维基百科页面（注：维基百科是一个任何人都可以编辑的在线百科全书）
New prophylactic and therapeutic strategies to combat human infections with highly pathogenic avian influenza (HPAI) H5N1 viruses are needed. We generated neutralizing anti-H5N1 human monoclonal antibodies (mAbs) and tested their efficacy for prophylaxis and therapy in a murine model of infection. Using Epstein-Barr virus we immortalized memory B cells from Vietnamese adults who had recovered from infections with HPAI H5N1 viruses. Supernatants from B cell lines were screened in a virus neutralization assay. B cell lines secreting neutralizing antibodies were cloned and the mAbs purified. The cross-reactivity of these antibodies for different strains of H5N1 was tested in vitro by neutralization assays, and their prophylactic and therapeutic efficacy in vivo was tested in mice. In vitro, mAbs FLA3.14 and FLD20.19 neutralized both Clade I and Clade II H5N1 viruses, whilst FLA5.10 and FLD21.140 neutralized Clade I viruses only. In vivo, FLA3.14 and FLA5.10 conferred protection from lethality in mice challenged with A/Vietnam/1203/04 (H5N1) in a dose-dependent manner. mAb prophylaxis provided a statistically significant reduction in pulmonary virus titer, reduced associated inflammation in the lungs, and restricted extrapulmonary dissemination of the virus. Therapeutic doses of FLA3.14, FLA5.10, FLD20.19, and FLD21.140 provided robust protection from lethality at least up to 72 h postinfection with A/Vietnam/1203/04 (H5N1). mAbs FLA3.14, FLD21.140 and FLD20.19, but not FLA5.10, were also therapeutically active in vivo against the Clade II virus A/Indonesia/5/2005 (H5N1). These studies provide proof of concept that fully human mAbs with neutralizing activity can be rapidly generated from the peripheral blood of convalescent patients and that these mAbs are effective for the prevention and treatment of H5N1 infection in a mouse model. A panel of neutralizing, cross-reactive mAbs might be useful for prophylaxis or adjunctive treatment of human cases of H5N1 influenza. Cameron Simmons and colleagues provide proof of concept that human monoclonal antibodies with neutralizing activity can be rapidly generated from peripheral blood of convalescent patients and are effective in preventing and treating H5N1 infection in a mouse model. Every year, millions of people catch influenza, a viral disease of the nose, throat, and airways. Although most recover, influenza outbreaks (epidemics) kill about half a million people annually. Epidemics occur because small but frequent changes in the viral proteins (antigens) to which the immune system responds mean that an immune response produced one year provides only partial protection against influenza the next year. Human flu viruses also occasionally appear that contain major antigenic changes. People have little or no immunity to such viruses (which often originate in animals or birds), so these viruses can start deadly pandemics—global epidemics. The Spanish flu pandemic in 1918/9, Asian flu in 1957, and Hong Kong flu in 1968 all killed millions. Experts believe that another pandemic is overdue and may be triggered by the avian H5N1 influenza virus—the name indicates that this bird virus carries type 5 hemagglutinin and type 1 neuraminidase, the two major flu antigens. H5N1, which rapidly kills infected birds, is now present in flocks around the world and, since 1997, it has caused 258 cases of human flu and 153 deaths. People have caught H5N1 through close contact with infected birds but, luckily, H5N1 rarely passes between people. H5N1 might acquire the ability to move between people and start a human influenza pandemic at any time. Some of the H5N1 viruses are resistant to the antiviral drugs used to treat flu and there will inevitably be a lag of some months between the emergence of a human pandemic H5N1 strain and the bulk production of a vaccine effective against it. Thus, new preventative and therapeutic strategies are needed to combat human infections with H5N1. One possibility is passive immunotherapy—treating people with antibodies (proteins that recognize antigens) that can stop H5N1 from infecting cells (so-called neutralizing antibodies). In this study, the researchers have generated neutralizing human monoclonal antibodies (laboratory-produced preparations that contain one type of human antibody) and tested their ability to halt viral growth in mice infected with H5N1. Patients who have survived infection with H5N1 make neutralizing antibodies, so the researchers isolated and immortalized the immune cells making these antibodies from the patients' blood. They grew up each cell separately and purified the antibody that the cells made. These monoclonal antibodies were then tested for their ability to neutralize H5N1 and other flu viruses in the laboratory. The researchers identified several that neutralized the H5N1 strain with which the patients were originally infected and chose two for further study. In the test tube, the four antibodies neutralized closely related H5N1 viruses and an H5N1 virus from a different lineage (clade) that has also caused human disease, in addition to the original H5N1 virus, although with different efficacies. In mice, the antibodies provided protection from infection with the original virus when given a day before or one to three days after infection. Three antibodies also partly protected the mice against H5N1 from a different clade. Finally, the researchers showed that the antibodies protected mice by limiting viral replication, by lessening the deleterious effects of the virus in the lungs, and by stopping viral spread out of the lungs. These results indicate that passive immunotherapy with human monoclonal antibodies could help to combat avian H5N1 if (or when) it starts a human pandemic. Passive immunotherapy is already used to prevent infections with several other viruses. In addition, a crude form of the approach—early treatment of patients with plasma (the liquid portion of blood) from convalescent patients—halved the death rate during the Spanish flu pandemic. Large amounts of pure monoclonal antibodies can be relatively easily made for clinical use, and this study indicates that some monoclonal antibodies neutralize H5N1 viruses from different clades. The researchers sound a note of caution, however: Before passive immunotherapy can help to halt an H5N1 pandemic, they warn, the monoclonal antibodies will have to be tested to see whether they can neutralize not only all the currently circulating H5N1 viruses but also any emerging pandemic versions, which might be antigenically distinct. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040178. US Centers for Disease Control and Prevention information about influenza for patients and professionals including key facts about avian influenza US National Institute of Allergy and Infectious Disease feature on seasonal, avian, and pandemic flu World Health Organization factsheet on influenza and information on avian influenza, including latest figures for confirmed human cases UK Health Protection Agency information on seasonal, avian, and pandemic influenza Wikipedia pages on passive immunity and monoclonal antibodies (note: Wikipedia is an online encyclopedia that anyone can edit)