Göttingen researchers have developed mini-antibodies that efficiently block the coronavirus Sars-CoV-2 and its dangerous new variants. These so-called nanobodies bind and neutralize the virus up to 1000 times better than previously developed mini-antibodies.
德國哥廷根大學城的研究人員們已經開發出，有效阻擾第二型嚴重急性呼吸系統徵候群-冠狀病毒(SARS-CoV-2：Severe Acute Respiratory Syndrome Coronavirus-2)及其危險新變種的微型抗體。此些所謂的奈米抗體，結合及中和病毒的能力，比先前開發的微型抗體更佳達1千倍。
In addition, the scientists optimized their mini-antibodies for stability and resistance to extreme heat. This unique combination makes them promising agents to treat Covid-19. Since nanobodies can be produced at low costs in large quantities, they could meet the global demand for Covid-19 therapeutics. The new nanobodies are currently in preparation for clinical trials.
此外，就穩定性及抗酷熱性，這些科學家優化了他們的微型抗體。這種獨特的組合，使它們成為治療2019冠狀病毒症(COVID-19：Coronavirus Disease-19)有指望的藥劑。因為，奈米抗體能以低成本、被大量生產。因此，它們可能滿足全球對Covid-19治療法的需求。目前，此些新的奈米抗體，正處於準備臨床試驗中。
圖1. 兩種新開發的奈米抗體(藍色及洋紅色)與冠狀病毒棘突蛋白(灰色)的受體結合域(綠色)結合，從而防止感染Sars-CoV-2及其變體。 (圖援用自原文)
Antibodies help our immune system to fend off pathogens. For example, the molecules attach to viruses and neutralize them so that they can no longer infect cells. Antibodies can also be produced industrially and administered to acutely ill patients.
抗體有助於咱們的免疫系統抵禦病原體。譬如，此些分子附著於病毒上，並中和它們。因此，它們不再感染細胞。抗體也可以工業化地被生產，並施予急性病患者。
They then act like drugs, relieving symptoms and shortening recovery from the disease. This is established practice for treating hepatitis B and rabies. Antibodies are also used for treating COVID-19 patients. However, producing these molecules on an industrial scale is too complex and expensive to meet worldwide demand. Nanobodies could solve this problem.
之後，它們起如同藥物作用，緩解症狀並縮短痊癒時間。這是治療B型肝炎及狂犬病的既定做法。抗體也被用於治療COVID-19病患。不過，以工業規模生產這些分子，太複雜且昂貴，無法滿足全球需求。奈米抗體可能解決此問題。
Scientists at the Max Planck Institute for Biophysical Chemistry in Göttingen (Germany) and the University Medical Center Göttingen have now developed mini-antibodies (also known as VHH antibodies or nanobodies) that unite all the properties required for a potent drug against Covid-19.
目前，位於(德國)哥廷根大學城的馬克斯普朗克生物物理化學研究所，及哥廷根大學醫學中心的科學家們業已開發出，結合了對抗Covid-19有效藥物，所需之所有屬性的微型抗體(也被通稱為VHH抗體或奈米抗體)。
“For the first time, they combine extreme stability and outstanding efficacy against the virus and its Alpha, Beta, Gamma, and Delta mutants,” emphasizes Dirk Görlich, director at the Max Planck Institute for Biophysical Chemistry.
馬克斯普朗克生物物理化學研究所所長，Dirk Görlich強調：「首次，它們結合了極度穩定性，及對抗該種病毒與其Alpha、Beta、Gamma及Delta突變種的顯著效力。」
At first glance, the new nanobodies hardly differ from anti-Sars-CoV-2 nanobodies developed by other labs. They are all directed against a crucial part of the coronavirus spikes, the receptor-binding domain that the virus deploys for invading host cells. The nanobodies block this binding domain and thereby prevent the virus from infecting cells.
乍看之下，此些新的奈米抗體與其他實驗室開發之抗SARS-CoV-2的奈米抗體，幾乎並無不同。它們全對準，此種冠狀病毒棘突的一處關鍵部位。這是該種病毒為了入侵宿主細胞，部署的受體結合域。這些奈米抗體阻擾了此結合域，從而防止此種病毒感染細胞。
“Our nanobodies can withstand temperatures of up to 95 °C without losing their function or forming aggregates,” explains Matthias Dobbelstein, professor and director of the University Medical Center Göttingen’s Institute of Molecular Oncology. “For one thing, this tells us that they might remain active in the body long enough to be effective. For another, heat-resistant nanobodies are easier to produce, process, and store.”
哥廷根大學醫學中心分子腫瘤學研究所教授兼主任，Matthias Dobbelstein解釋：「他們的奈米抗體能經得起高達95°C的溫度，不會失去其功能或形成聚集體。一方面，這告訴人們，它們能在體內保持夠長、有效的活躍時間。另一方面，耐熱的奈米抗體較容易生產、處理及儲存。」
The simplest mini-antibodies developed by the Göttingen team already bind up to 1000 times more strongly to the spike protein than previously reported nanobodies. They also bind very well to the mutated receptor-binding domains of the Alpha, Beta, Gamma, and Delta strains.
由此哥廷根團隊所開發的最簡單微型抗體，與棘突蛋白的結合強度，已經是先前報導之奈米抗體的1千倍。它們也牢固地，與Alpha、Beta、Gamma及Delta病毒株，突變的受體結合域結合。
“Our single nanobodies are potentially suitable for inhalation and thus for direct virus neutralization in the respiratory tract,” Dobbelstein says. “In addition, because they are very small, they could readily penetrate tissues and prevent the virus from spreading further at the site of infection.”
Dobbelstein宣稱：「他們的單式奈米抗體，潛在上適合吸入。因此，適用於直接中和呼吸道中的病毒。此外，由於非常細小，它們能容易穿透組織，及防止病毒於感染部位，進一步擴散。」
A ‘nanobody triad’ further improves binding: The researchers bundled three identical nanobodies according to the symmetry of the spike protein, which is comprised of three identical building blocks with three binding domains.
一種‘三合體的奈米抗體’進一步改善了結合狀態：也就是，根據棘突蛋白的對稱性，此些研究人員將，由三個具有三個結合域之相同構材組成的完全相同奈米抗體，捆綁在一起。
“With the nanobody triad, we literally join forces: In an ideal scenario, each of the three nanobodies attaches to one of the three binding domains,” reports Thomas Güttler, a scientist in Görlich’s team. “This creates a virtually irreversible bond. The triple will not let release the spike protein and neutralizes the virus even up to 30,000-fold better than the single nanobodies.”
於Görlich團隊中的科學家，Thomas Güttler記述：「以該種三合體的奈米抗體方式，他們確實結合了諸多效力：在理想的腳本下，這三個中的每一奈米抗體，皆附著於上述三個結合域之一上。這創造了一種幾乎不可逆的結合。這種三合體不會釋放棘突蛋白，且中和該種病毒，甚至比單式奈米抗體，更佳高達3萬倍。」
Another advantage: The larger size of the nanobody triad expectedly delays renal excretion. This keeps them in the body for longer and promises a longer-lasting therapeutic effect.
另一個優勢：該種三合體之奈米抗體的較大尺寸，預期會拖延腎臟的排泄。 這使它們於體內停留更長時間，因此有指望維持更長療效。
As a third design, the scientists produced tandems. These combine two nanobodies that target different parts of the receptor-binding domain and together can bind the spike protein. “Such tandems are extremely resistant to virus mutations and the resulting ‘immune escape’ because they bind the viral spike so strongly”, explains Metin Aksu, a researcher in Görlich’s team.
作為第三種設計，此些科學家製作了串聯的奈米抗體。此些組合了兩個鎖定，受體結合域不同部位的奈米抗體，能一起與棘突蛋白結合。於Görlich 團隊中的研究員，Metin Aksu解釋：「這種串聯的奈米抗體，對病毒突變體及由此產生的‘免疫逃逸’具有極強的抵抗力。因為，它們與病毒棘突結合得非常牢固。」
For all nanobody variants – monomeric, double as well as triple – the researchers found that very small amounts are sufficient to stop the pathogen. If used as a drug, this would allow for a low dosage and thus for fewer side effects and lower production costs.
就所有的奈米抗體變異體(單體、雙體及三合體)而言，此些研究人員發現，極少量就足以阻止該種病原體。如果被使用作為藥物，這可能為低劑量及，從而較少的副作用與較低的生產成本做好準備。
“Our nanobodies originate from alpacas and are smaller and simpler than conventional antibodies,” Görlich says.
Görlich宣稱：「我們源自羊駝的奈米抗體，比傳統抗體更小且更簡單。」
To generate the nanobodies against Sars-CoV-2, the researchers immunized three alpacas – Britta, Nora, and Xenia from the herd at the Max Planck Institute for Biophysical Chemistry – with parts of the coronavirus spike protein. The mares then produced antibodies, and the scientists drew a small blood sample from the animals.
為了產生對抗Sars-CoV-2的奈米抗體，此些研究人員使用該種冠狀病毒棘突蛋白的部分，使來自馬克斯普朗克生物物理化學研究所，羊駝群中的Britta、Nora及Xenia三隻羊駝，產生免疫力。之後，此些母羊駝產生抗體，然後這些科學家從此些動物，抽取少量血液樣本。
For the alpacas, the mission was then complete, as all further steps were carried out with the help of enzymes, bacteria, so-called bacteriophages, and yeast. “The overall burden on our animals is very low, comparable to vaccination and blood testing in humans,” Görlich explains.
就此些羊駝而言，那樣任務就完成了。因為，所有進一步的步驟，全是在酵素、細菌、所謂的噬菌體及酵母菌的協助下進行。Görlich解釋：「他們的動物總體負荷非常低，可媲美人類中的疫苗接種及血液檢測。」
Görlich’s team extracted around one billion blueprints for nanobodies from the alpacas’ blood. What then followed was a laboratory routine perfected over many years: The biochemists used bacteriophages to select the very best nanobodies from the initially vast pool of candidates. These were then tested for their efficacy against Sars-CoV-2 and further improved in successive rounds of optimization.
從羊駝的血液中，Görlich團隊獲得了，大約10億張奈米抗體藍圖。之後，接下來的是，經過多年完善的實驗室例行程序：也就是，此些生物化學家使用了噬菌體，從最初龐大的候選庫中，選擇最佳的奈米抗體。之後，測試了它們對抗Sars-CoV-2的效力，並在連續幾輪優化中，進一步進行改善。
Not every antibody is ‘neutralizing’. Researchers of Dobbelstein’s group therefore determined if and how well the nanobodies prevent the viruses from replicating in cultured cells in the lab. “By testing a wide range of nanobody dilutions, we find out which quantity suffices to achieve this effect,” explains Antje Dickmanns from Dobbelstein’s team.
並非每一抗體皆‘起中和作用’。因此，Dobbelstein團隊的研究人員們確定了，在實驗室培養之細胞中的複製，此些奈米抗體是否及多充分防止病毒。來自Dobbelstein團隊的Antje Dickmanns解釋：「藉由檢測廣泛的奈米抗體稀釋度，他們找出了哪種數量，足夠達到這種效力。」
Her colleague Kim Stegmann adds: “Some of the nanobodies were really impressive. Less than a millionth of a gram per liter of medium was enough to completely prevent infection. In the case of the nanobody triads, even another twenty-fold dilution was sufficient. ”
她的同僚Kim Stegmann附言：「其中有些奈米抗體，確實令人印象深刻。每公升培養基不到百萬分之一克，足以完全防止感染。在三合體之奈米抗體的情況下，甚至再稀釋20倍也是足夠。」
Over the course of the coronavirus pandemic, new virus variants have emerged and rapidly became dominant. These variants are often more infectious than the strain that first appeared in Wuhan (China). Their mutated spike protein can also ‘escape’ neutralization by some originally effective antibodies of infected, recovered, or vaccinated persons.
在此冠狀病毒大流行的過程中，新的病毒變異體已經出現，且迅速成為優勢種。這些變異體通常比最早出現於武漢(中國)的病毒株，更具傳染性。它們突變的棘突蛋白也能‘避開’，由一些對遭感染者、康復者或接種疫苗者，原本有效之抗體的中和作用。
This makes it more difficult even for an already trained immune system to eliminate the virus. This problem also affects previously developed therapeutic antibodies and nanobodies.
這使其甚至對已經被培養的免疫系統而言，也更難以根除該種病毒。此問題也影響了，先前開發的治療性抗體及奈米抗體。
This is where the new nanobodies show their full potential, as they are also effective against the major coronavirus variants of concern. The researchers had inoculated their alpacas with part of the spike protein of the first known Sars-CoV-2 virus, but remarkably, the animals’ immune system also produced antibodies that are active against the different virus variants.
這是新奈米抗體展現其充分潛力之處，因為它們對抗令人擔憂的主要冠狀病毒變異體，也是有效的。此些研究人員已經使用，第一種已知之Sars-CoV-2病毒的棘突蛋白部分，接種了他們的羊駝。不過引人注目的是，此些動物的免疫系統也產生了，對此些不同病毒變異體是活性的抗體。
“Should our nanobodies prove ineffective against a future variant, we can reimmunize the alpacas. Since they have already been vaccinated against the virus, they would very quickly produce antibodies against the new variant,” Güttler asserts confidently.
Güttler有信心地斷言：「萬一他們的奈米抗體證實對未來的變異體無效，他們能再度使此些羊駝免疫。由於，牠們已經被接種過對抗此種病毒的疫苗。因此，牠們會很快產生對抗新變異體的抗體。」
The Göttingen team is currently preparing the nanobodies for therapeutic use. Dobbelstein emphasizes: “We want to test the nanobodies as soon as possible for safe use as a drug so that they can be of benefit to those seriously ill with Covid-19 and those who have not been vaccinated or cannot build up an effective immunity.”
目前，哥廷根團隊正進行準備，供治療用途的奈米抗體。Dobbelstein強調：「他們想儘快測試此些奈米抗體，供安全使用作為一種藥物，以便它們對那些罹患Covid-19重症及未接種疫苗，或無法建立有效免疫力者，會是有益的。」
The team is supported by experts in technology transfer: Dieter Link (Max Planck Innovation), Johannes Bange (Lead Discovery Center, Dortmund, Germany), and Holm Keller (kENUP Foundation). The Max Planck Foundation provides financial support for the project.
在技術轉移方面，該團隊獲得了，Dieter Link(Max Planck Innovation)、Johannes Bange(Lead Discovery Center, Dortmund, Germany)及Holm Keller(kENUP 基金會)等，專家的支援。馬克斯普朗克基金會為該計劃，提供財務支援。
The receptor-binding domain of Sars-CoV-2 is known to be a good candidate for a protein vaccine but so far difficult to manufacture economically on a large scale and in a form, which activates the immune system against the virus. Bacteria programmed accordingly produce incorrectly folded material.
眾所周知，Sars-CoV-2的受體結合域，是蛋白質疫苗的一種良好候選物。不過迄今為止，很難以一種活化免疫系統，來對抗此種病毒的方式，且具經濟性地大規模進行生產。相應地，經編碼指令程序的細菌，會產生不正確摺疊的材料。
The Göttingen researchers discovered a solution for this problem: They identified special nanobodies that enforce correct folding in bacterial cells, without obstructing the crucial neutralizing part of the receptor-binding domain.
此些哥廷根的研究人員發現了，此問題的一種解決方案：他們確認了，於細菌細胞中，強制正確折疊而不會阻礙，受體結合域之關鍵中和部分的特殊奈米抗體。
This might allow for vaccines that can be produced inexpensively, can be quickly adapted to new virus variants, and can be distributed with simple logistics even in countries with little infrastructure.
這可能為，會是廉價被生產、會是快速適合新病毒變異體，及甚至在基礎設施很少的國家中，能以簡易後勤法被分送的疫苗，做準備。
“The fact that nanobodies can help with protein folding was previously not known and is extremely interesting for research and pharmaceutical applications,” Görlich says.
Görlich宣稱：「奈米抗體能協助蛋白質折疊的事實，先前是未知的。這對研究及製藥應用是極度令人關注的。」
網址：https://www.mpg.de/17271996/0722-nanobodies?c=2249
翻譯: 許東榮
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