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Nature:人体肌肉细胞化“兵工厂”成为抗HIV的“抗体常备军”

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发表于 2015-4-28 12:34:36 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
本帖最后由 ipsvirus 于 2015-4-28 12:37 编辑

   艾滋病正式名称为“后天免疫缺乏症候群”(AIDS),其病毒于19世纪末至20世纪初起源于非洲中西部。1981年6月6日,美国疾病管制局(CDC)通报全球首宗艾滋病毒感染案例。1981年迄今的33年间,艾滋病毒感染了超过7800万人,夺走3600万人的生命。2013年,全球新增210万病例,150万人死亡。目前全球约有3530万艾滋病患与带原者,其中男性约1720万人、女性约1680万人,虽然已较2001年减少38%,然而只有1360万病患得到药物治疗。艾滋病疫情在撒哈拉沙漠以南的非洲(sub-Saharan Africa),总病例数2500万人占全球68%,死亡120万人占66%。南非有590万艾滋病患,是全球第一艾滋大国。

   开发艾滋病疫苗是全球面临的重要任务和挑战。尽管艾滋病病毒已发现30多年,但由于其多变和多样性,迄今还没有一种针对该病的疫苗能投入使用。

   Nature一篇论文报道了一种新的蛋白和一种新的疫苗思路,二者结合,也许会成为抗击艾滋病的新希望。

   传统疫苗接种的原理是试图教会人体免疫系统抗击进犯的外敌——让免疫系统对敌人敏感,下次遇敌能很快合成相应抗体。可惜这一招多年来对于HIV始终难以奏效,部分原因是HIV突变太快了,每次都不完全一样。

   而新的打法基于完全不同的原理:人工设计一种更好的蛋白来充当抗体,让病毒误以为这是细胞并和它牢牢结合;然后利用基因疗法,让人体不管三七二十一都持续合成这种蛋白,形成一支“常备军”,而不用等到发现病毒再临时征召。

      eCD4-Ig“以伪装拒绝病毒”
   这一方案来自美国加州斯克里普斯研究所(Scripps Research Institute, California)的研究者。首先,他们利用现有技术精心设计了一种载体——经过改造的无害腺相关病毒的DNA片段;然后将其注入肌肉组织。这个片段很小,不会自我复制也不会整合到细胞基因组里,但它能够刺激细胞,让细胞按照它的代码来源源不断合成一种名叫eCD4-Ig的类抗体蛋白。这种蛋白质产量充足,持续时间也可长达数年,甚至是数十年。然后,这种蛋白就会浩浩荡荡地进入血液,对艾滋病毒的攻击目标——人体重要免疫细胞CD4细胞形成强有力的保护。这里的保护原理比较复杂,但简而言之,CD4细胞上有两个“入口”:CD4和CCR5两种受体,艾滋病毒要和它们结合才能入侵细胞;现在这种保护蛋白假装自己是这两个入口,欺骗病毒,让病毒以为自己结合到了细胞上——但一旦结合就下不来了。这种蛋白的结构还经过精心设计,让病毒很难通过改变自身形状而挣脱。体外实验显示,这种药物可阻止人类艾滋病病毒1型(HIV-1)和2型(HIV-2)的各种已知病毒株的感染,其有效性远高于现有效果最好的广谱抗爱药。

   恒河猴实验成功
   利用恒河猴进行的动物实验显示,事先注射这种药物的4只恒河猴在8个多月的时间里多次、大剂量接触猴类版本的艾滋病病毒后无一感染,而未接受治疗的对照组恒河猴全部死亡。负责研究的美国斯克里普斯研究所(Scripps Research Institute)教授法尔赞(Michael Farzan)在一份声明中说:“我们研制的药物是迄今已知最广谱、最有效的进入抑制剂。与无法‘中和’绝大部分艾滋病病毒毒株的抗体不一样,我们的蛋白对所有接受测试的毒株都有效,这说明它可能提供了有效艾滋病疫苗的一种替代方案。”

  效果可持续数年
   法尔赞还表示,这种药物注射入肌肉后,人体免疫细胞产生山寨版CD4和CCR5受体的能力可能持续数年乃至数十年。美国国家过敏症和传染病研究所(NIAID)所长佛契(Anthony Fauci)发表声明说,这一成果是朝着艾滋病患者获得持续缓解的目标迈出的“重要一步”。《自然》杂志的一篇观点文章指出,该研究使用的恒河猴样本数量太少,还需进行更大规模的动物实验,同时也要研究人类使用该药物的安全性问题。然而,监于目前没有艾滋病疫苗,近来在这方面也没有重大突破,利用这种药物取得类似疫苗的持续保护效果“值得考虑”。
   
   明年之内,该团队将针对无法接受传统药物治疗的HIV感染者展开试验,但他们也面临着相当大的挑战:最大的一项当然是安全性。在常规的疫苗接种方案中,接种后的人体免疫系统当且仅当外敌入侵时才会产生应答。然而如上文所述,这种基因疗法会令人体肌肉细胞转化为一座长期不断地大量生产人造抗HIV药物的“兵工厂”,换言之,接受这种治疗的HIV感染者的远期安全效应目前还不明朗。因此,实验者会先向志愿者体内注射这一蛋白本身,一定时间后再尝试注射载体。
   
     然而若考虑目前现代医学在与艾滋病的战争中所陷入的泥淖——尚无疫苗能够激发人体对HIV产生全面有效的免疫,同时在治疗方面也已经有很长时期未能实现真正的突破——这种崭新的治疗方案的确令人充满期待:人类或许从来没有如此接近征服艾滋病,令未感染者长期免疫,令感染者免于发病。
来源:果壳网,风传媒(编者整理)

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 楼主| 发表于 2015-4-28 12:38:50 | 只看该作者
AAV-expressed eCD4-Ig provides durable protection from multiple SHIV challenges

Matthew R. Gardner,        Lisa M. Kattenhorn,        Hema R. Kondur,        Markus von Schaewen, Tatyana Dorfman,        Jessica J. Chiang,        Kevin G. Haworth,        Julie M. Decker,        Michael D. Alpert, Charles C. Bailey,        Ernest S. Neale,        Christoph H. Fellinger,        Vinita R. Joshi,        Sebastian P. Fuchs,        Jose M. Martinez-Navio,        Brian D. Quinlan,        Annie Y. Yao,        Hugo Mouquet,        Jason Gorman,        Baoshan Zhang,        Pascal Poignard,        Michel C. Nussenzweig,        Dennis R. Burton, Peter D. Kwong,        Michael Piatak,        Jeffrey D. Lifson,        Guangping Gao,        Ronald C. Desrosiers, David T. Evans,        Beatrice H. Hahn,        Alexander Ploss,        Paula M. Cannon,        Michael S. Seaman        & Michael Farzan       

Long-term in vivo expression of a broad and potent entry inhibitor could circumvent the need for a conventional vaccine for HIV-1. Adeno-associated virus (AAV) vectors can stably express HIV-1 broadly neutralizing antibodies (bNAbs)1, 2. However, even the best bNAbs neutralize 10–50% of HIV-1 isolates inefficiently (80% inhibitory concentration (IC80) > 5 μg ml−1), suggesting that high concentrations of these antibodies would be necessary to achieve general protection3, 4, 5, 6. Here we show that eCD4-Ig, a fusion of CD4-Ig with a small CCR5-mimetic sulfopeptide, binds avidly and cooperatively to the HIV-1 envelope glycoprotein (Env) and is more potent than the best bNAbs (geometric mean half-maximum inhibitory concentration (IC50) < 0.05 μg ml−1). Because eCD4-Ig binds only conserved regions of Env, it is also much broader than any bNAb. For example, eCD4-Ig efficiently neutralized 100% of a diverse panel of neutralization-resistant HIV-1, HIV-2 and simian immunodeficiency virus isolates, including a comprehensive set of isolates resistant to the CD4-binding site bNAbs VRC01, NIH45-46 and 3BNC117. Rhesus macaques inoculated with an AAV vector stably expressed 17–77 μg ml−1 of fully functional rhesus eCD4-Ig for more than 40 weeks, and these macaques were protected from several infectious challenges with SHIV-AD8. Rhesus eCD4-Ig was also markedly less immunogenic than rhesus forms of four well-characterized bNAbs. Our data suggest that AAV-delivered eCD4-Ig can function like an effective HIV-1 vaccine.

http://www.nature.com/nature/jou ... .html#extended-data

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 楼主| 发表于 2015-4-28 12:57:45 | 只看该作者
最近不是有个3BNC117的有效抗体在人体临床上进行了试验,效果很好嘛。(详见Nature:新型艾滋病抗体“3BNC117"首个临床试验效果明显http://bbs.virology.com.cn/forum.php?mod=viewthread&tid=1500

那把这个抗体改造下能在体内长期产生抗体,是不是可以有长期免疫保护效果?

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发表于 2015-4-28 17:28:26 | 只看该作者
本帖最后由 marine0425030 于 2015-4-28 18:13 编辑

多谢ipsvirus 兄发帖,我也来个锦上添花之举吧。

那么就先来说说这个VIP(vectored immunoprophylaxis)的概念吧。利用腺伴随病毒(adeno associated virus,AAV)作为载体将表达HIV中和抗体的基因运送到肌肉组织中,让其不断的产生抗体从而可以中和前来进犯的病毒们。
这个概念很多人都说是诺贝尔奖获得者加州理工的David Baltimore教授开发的,也有一部分说不是,这个是由费城儿童医院的Phillip Johnson开发的。
好吧,反正不是我开发的。目前,费城儿童医院和美国NIAID也正在进行临床一期试验的,他们用AAV1表达一种光谱抗体PG9。不过目前还没发布任何试验结果,网页上写着预期2016年吧。


咱就看看回顾下之前发过的主要文章吧。

1. Nature Medicine 15, 901 - 906 (2009)
Vector-mediated gene transfer engenders long-lived neutralizing activity and protection against SIV infection in monkeys
Philip R Johnson1, Bruce C Schnepp1, Jianchao Zhang2, Mary J Connell1, Sean M Greene1, Eloisa Yuste3, Ronald C Desrosiers3 & K Reed Clark2

Abstract
The key to an effective HIV vaccine is development of an immunogen that elicits persisting antibodies with broad neutralizing activity against field strains of the virus. Unfortunately, very little progress has been made in finding or designing such immunogens. Using the simian immunodeficiency virus (SIV) model, we have taken a markedly different approach: delivery to muscle of an adeno-associated virus gene transfer vector expressing antibodies or antibody-like immunoadhesins having predetermined SIV specificity. With this approach, SIV-specific molecules are endogenously synthesized in myofibers and passively distributed to the circulatory system. Using such an approach in monkeys, we have now generated long-lasting neutralizing activity in serum and have observed complete protection against intravenous challenge with virulent SIV. In essence, this strategy bypasses the adaptive immune system and holds considerable promise as a unique approach to an effective HIV vaccine.
论坛链接:美打破常规寻找艾滋病疫苗研发新途径 http://bbs.virology.com.cn/thread-2300-1-1.html


2.Nature,481,81–84 (05 January 2012)
Antibody-based protection against HIV infection by vectored immunoprophylaxis

Alejandro B. Balazs, Joyce Chen,Christin M. Hong,Dinesh S. Rao,Lili Yang & David Baltimore

Despite tremendous efforts, development of an effective vaccine against human immunodeficiency virus (HIV) has proved an elusive goal. Recently, however, numerous antibodies have been identified that are capable of neutralizing most circulating HIV strains1, 2, 3, 4, 5. These antibodies all exhibit an unusually high level of somatic mutation6, presumably owing to extensive affinity maturation over the course of continuous exposure to an evolving antigen7. Although substantial effort has focused on the design of immunogens capable of eliciting antibodies de novo that would target similar epitopes8, 9,10, it remains uncertain whether a conventional vaccine will be able to elicit analogues of the existing broadly neutralizing antibodies. As an alternative to immunization, vector-mediated gene transfer could be used to engineer secretion of the existing broadly neutralizing antibodies into the circulation. Here we describe a practical implementation of this approach, which we call vectored immunoprophylaxis (VIP), which in mice induces lifelong expression of these monoclonal antibodies at high concentrations from a single intramuscular injection. This is achieved using a specialized adeno-associated virus vector optimized for the production of full-length antibody from muscle tissue. We show that humanized mice receiving VIP appear to be fully protected from HIV infection, even when challenged intravenously with very high doses of replication-competent virus. Our results suggest that successful translation of this approach to humans may produce effective prophylaxis against HIV.

原文链接:http://pathology.ucla.edu/workfiles/Research/nature10660.pdf
论坛链接:Nature:艾滋病基因疗法在动物体内效果显著
http://bbs.virology.com.cn/thread-379-1-1.html


3. Nature Medicine 20, 296–300 (2014)
Vectored immunoprophylaxis protects humanized mice from mucosal HIV transmission

Alejandro B Balazs,Yong Ouyang,Christin M Hong,Joyce Chen,Steven M Nguyen,Dinesh S Rao,Dong Sung An& David Baltimore

The vast majority of new HIV infections result from relatively inefficient transmission1, 2 of the virus across mucosal surfaces during sexual intercourse3. A consequence of this inefficiency is that small numbers of transmitted founder viruses initiate most heterosexual infections4. This natural bottleneck to transmission has stimulated efforts to develop interventions that are aimed at blocking this step of the infection process5. Despite the promise of this strategy, clinical trials of preexposure prophylaxis have had limited degrees of success in humans, in part because of lack of adherence to the recommended preexposure treatment regimens6, 7. In contrast, a number of existing vaccines elicit systemic immunity that protects against mucosal infections, such as the vaccines for influenza8 and human papilloma virus9. We recently demonstrated the ability of vectored immunoprophylaxis (VIP) to prevent intravenous transmission of HIV in humanized mice using broadly neutralizing antibodies10. Here we demonstrate that VIP is capable of protecting humanized mice from intravenous as well as vaginal challenge with diverse HIV strains despite repeated exposures. Moreover, animals receiving VIP that expresses a modified VRC07 antibody were completely resistant to repetitive intravaginal challenge by a heterosexually transmitted founder HIV strain11, suggesting that VIP may be effective in preventing vaginal transmission of HIV between humans.

原文链接:http://balazslab.mgh.harvard.edu/pdfs/Nat.%20Med.-Balazs,2014.pdf
论坛链接:诺奖得主Nature子刊发表艾滋病研究重要成果
http://www.ebiotrade.com/newsf/2014-2/2014211163547833.htm


4. Nature Biotechnology 31, 647–652 (2013)
Broad protection against influenza infection by vectored immunoprophylaxis in mice
Alejandro B Balazs,Jesse D Bloom,Christin M Hong,Dinesh S Rao& David Baltimore

Neutralizing antibodies that target epitopes conserved among many strains of influenza virus have been recently isolated from humans. Here we demonstrate that adeno-associated viruses (AAV) encoding two such broadly neutralizing antibodies are protective against diverse influenza strains. Serum from mice that received a single intramuscular AAV injection efficiently neutralized all H1, H2 and H5 influenza strains tested. After infection with diverse strains of H1N1 influenza, treated mice showed minimal weight loss and lung inflammation. Protection lasted for at least 11 months after AAV injection. Notably, even immunodeficient and older mice were protected by this method, suggesting that expression of a monoclonal antibody alone is sufficient to protect mice from illness. If translated to humans, this prophylactic approach may be uniquely capable of protecting immunocompromised or elderly patient populations not reliably protected by existing vaccines.

原文链接:http://balazslab.mgh.harvard.edu/pdfs/Nat.%20Biotech.-Balazs,2013.pdf
论坛链接:VIP,诺奖得主打造对抗疾病的新利器 http://www.ebiotrade.com/newsf/2014-9/2014919141841733.htm



5.Sci Transl Med 17 September 2014
Broadly neutralizing antibodies abrogate established hepatitis C virus infection
Ype P. de Jong1,2,*,Marcus Dorner2,†,Michiel C. Mommersteeg2,Jing W. Xiao2,Alejandro B. Balazs3,Justin B. Robbins4,Benjamin Y. Winer5,Sherif Gerges5,Kevin Vega2,Rachael N. Labitt2,Bridget M. Donovan2,Erick Giang4,Anuradha Krishnan6,Luis Chiriboga7,Michael R. Charlton6,Dennis R. Burton3,4,David Baltimore8,Mansun Law4,Charles M. Rice2 andAlexander Ploss2,5,*

In most exposed individuals, hepatitis C virus (HCV) establishes a chronic infection; this long-term infection in turn contributes to the development of liver diseases such as cirrhosis and hepatocellular carcinoma. The role of antibodies directed against HCV in disease progression is poorly understood. Neutralizing antibodies (nAbs) can prevent HCV infection in vitro and in animal models. However, the effects of nAbs on an established HCV infection are unclear. We demonstrate that three broadly nAbs—AR3A, AR3B, and AR4A—delivered with adeno-associated viral vectors can confer protection against viral challenge in humanized mice. Furthermore, we provide evidence that nAbs can abrogate an ongoing HCV infection in primary hepatocyte cultures and in a human liver chimeric mouse model. These results showcase a therapeutic approach to interfere with HCV infection by exploiting a previously unappreciated need for HCV to continuously infect new hepatocytes to sustain a chronic infection.

原文链接:http://stm.sciencemag.org/content/6/254/254ra129.abstract
论坛链接:VIP,诺奖得主打造对抗疾病的新利器http://science.bio1000.com/sciencecover/201409/86.html


6.Nature Immunology 14, 1–5 (2013)  Review
Antibody gene transfer for HIV immunoprophylaxis
原文链接:http://balazslab.mgh.harvard.edu/pdfs/Nat.%20Immunol.-Balazs,2012.pdf


7. PNAS,August 26, 2014 Vectored antibody gene delivery protects against Plasmodium falciparum sporozoite challenge in mice
Abstract
Malaria caused by Plasmodium falciparum kills nearly one million children each year and imposes crippling economic burdens on families and nations worldwide. No licensed vaccine exists, but infection can be prevented by antibodies against the circumsporozoite protein (CSP), the major surface protein of sporozoites, the form of the parasite injected by mosquitoes. We have used vectored immunoprophylaxis (VIP), an adeno-associated virus-based technology, to introduce preformed antibody genes encoding anti-P. falciparum CSP mAb into mice. VIP vector-transduced mice exhibited long-lived mAb expression at up to 1,200 µg/mL in serum, and up to 70% were protected from both i.v. and mosquito bite challenge with transgenic Plasmodium berghei rodent sporozoites that incorporate the P. falciparum target of the mAb in their CSP. Serum antibody levels and protection from mosquito bite challenge were dependent on the dose of the VIP vector. All individual mice expressing CSP-specific mAb 2A10 at 1 mg/mL or more were completely protected, suggesting that in this model system, exceeding that threshold results in consistent sterile protection. Our results demonstrate the potential of VIP as a path toward the elusive goal of immunization against malaria.
论坛链接:PNAS:可持续性抵御疟疾感染的新型候选疫苗 http://news.bioon.com/article/6656910.html



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发表于 2015-4-28 17:50:53 | 只看该作者
本帖最后由 marine0425030 于 2015-4-28 18:09 编辑

俺在想,HIV-1没啥好法子,弄个载体在肌肉里专门放抗体也就罢了,流感啥的有这个必要?

不过,我对这个第一作者产生了兴趣,一查,他去了Ragon Institute of MGH, MIT and Harvard,哈哈!

http://balazslab.mgh.harvard.edu/ 希望可以见到他。

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 楼主| 发表于 2015-4-28 20:06:29 | 只看该作者
marine0425030 发表于 2015-4-28 17:50
俺在想,HIV-1没啥好法子,弄个载体在肌肉里专门放抗体也就罢了,流感啥的有这个必要?

不过,我对这个第 ...

marine0425030兄,我想对你说,你再这么犀利下去,我们都不好作朋友了好吧


David Baltimore影响力更大啊,再加上后面他将这个技术都做了其他病毒,基本是霸主级别了。
最近我们实验室的流感Group就有用这个技术,我们从病人里找到了一个广谱性的抗体,还解了结构,binding位点还挺特别的(还没发文章,不能透露太多,嘿嘿)。在小鼠实验上就用AAV将这个抗体基因打到小鼠肌肉,然后攻毒,效果还是不错的。对于流感来说吧,我是觉得VIP现在就是个实验方法了。

当然前景也还是有的,哪天我们可以将AAV改造下,对肺上皮细胞有特异性感染。这样的话就可以把这类装有广谱抗体基因的AAV制成喷剂,到时候我们去接种流感疫苗就不要打针了,只要进行喷雾接种,特异性的感染肺上皮细胞产生广谱抗体,产生保护作用,直接就在感染的时候就阻断了,嘎嘎,想想就是另一片天空啊

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 楼主| 发表于 2015-4-28 20:07:46 | 只看该作者
marine0425030 发表于 2015-4-28 17:50
俺在想,HIV-1没啥好法子,弄个载体在肌肉里专门放抗体也就罢了,流感啥的有这个必要?

不过,我对这个第 ...

大神,你要去哈佛啊

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 楼主| 发表于 2015-4-28 20:07:47 | 只看该作者
marine0425030 发表于 2015-4-28 17:50
俺在想,HIV-1没啥好法子,弄个载体在肌肉里专门放抗体也就罢了,流感啥的有这个必要?

不过,我对这个第 ...

大神,你要去哈佛啊

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9#
发表于 2015-4-30 08:44:35 | 只看该作者
ipsvirus 发表于 2015-4-28 20:06
marine0425030兄,我想对你说,你再这么犀利下去,我们都不好作朋友了好吧

嗯,那很不错啊,筛抗体需要蛮长的时间呢,希望你们能发篇好文章。

呵呵,你那对前景的想法很不错啊。

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发表于 2015-4-30 08:46:00 | 只看该作者
ipsvirus 发表于 2015-4-28 20:07
大神,你要去哈佛啊



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