Could this technology end all viruses?

Translator: Chloe Lau Reviewer: Thomas Tam

This round structure is only about ten billionths of a meter in diameter,

呢個圓形嘅結構直徑 只有百億分之一米

but it— as well as other technologies in the pipeline—

但係佢以及其他接踵而來嘅科技

could be stepping stones to a monumental public health ambition:

可能係劃時代嘅 公共衛生野心嘅踏腳石：

a single vaccine that protects you against everything.

能保護你對抗一切流感嘅單一疫苗

We’ll get back to the grand vision later, but first,

我哋等一下會提到 呢個雄偉嘅憧憬

let’s start with something that’s being developed now:

但我哋先從現在正研發嘅嘢講起：

a vaccine that would protect you against every strain of the flu—

一個保護你對抗 任何流感病毒株嘅疫苗

even ones that don’t exist yet.

就算係仲未存在嘅病毒株

Here’s one flu virus particle.

呢個係一粒流感病毒

On the inside is the virus’ RNA,

裏面係病毒嘅 RNA

and on the outside are lots and lots of hemagglutinin proteins.

外面有許許多多血凝素蛋白質

Hemagglutinin attaches to a receptor on a human cell

血凝素附著於人體細胞嘅受體

and fuses the viral and human membranes, starting the infection.

融合病毒同埋人體嘅 細胞膜開始感染

Hemagglutinin is also one of the things your immune system recognizes

血凝素亦都係你免疫系統辨識

and reacts to the most.

同反應最多嘅嘢之一

To understand how this works,

要明白呢個係點樣運作

think of hemagglutinin as a bust of 19th century French Emperor Napoleon Bonaparte.

可以諗下血凝素係19世紀 法國皇帝拿破崙波拿巴嘅半身像

Croissant!

可頌！

If you show Napoleon to an immune system and say, “remember him,”

如果你向免疫系統展示拿破崙 然後話：「記住佢」

the immune system will mostly focus on his head.

免疫系統主要會注意佢嘅頭部

And the same is true for the real hemagglutinin.

血凝素亦係一樣

One way the immune system remembers things

免疫系統記住嘢嘅辦法之一

is by physically interacting with them.

係同佢哋進行身體互動

Think of it as making plaster molds of parts of the head:

把佢想像成塑造石膏頭像嘅模具：

we call these molds antibodies.

呢啲模具叫做抗體

The antibodies float around your bloodstream for a while

抗體喺我哋血液周圍浮動一陣

and then can diminish,

然後會慢慢消失

but blueprints on how to make them are stored in specialized memory cells,

但係點樣整佢哋嘅藍圖 會儲存喺專門記憶嘅細胞入面

waiting for future Napoleons to invade.

等緊未來拿破崙嘅入侵

Here’s the thing, though.

可是有一啲嘢

Hemagglutinin is constantly mutating.

血凝素一直噉喺度突變

Most mutations are subtle,

多數嘅突變係微妙嘅

produced by single letter changes in the virus’ RNA: like this or this.

淨係變咗病毒RNA一個字母： 似呢個抑或嗰個

Over time, Napoleon-slash-hemagglutinin’s head can change enough

過一段時間 拿破崙或血凝素嘅頭

that our antibodies become less good at recognizing it.

可能變得多 使到抗體都辨認唔到

This is called antigenic drift.

呢個叫做抗原漂移

Influenza is constantly drifting;

流感一直係噉漂移

that’s one reason you have to get a new flu shot every year.

呢個係你每年都要打 新流感針嘅原因之一

But sometimes bigger changes happen.

但有時候亦會發生比較大嘅改變

An animal, usually a pig, can get infected with, say,

一隻動物，通常係豬 可能會同時感染到

a human flu and a bird flu.

比方說，人類同埋鳥類嘅流感

And those different viruses might infect the same cell.

呢兩種病毒可能感染 喺同一個細胞度

If that happens, the two different viral genomes can recombine

如果發生噉樣嘅事 呢兩個病毒嘅基因組

in tens or even hundreds of ways.

就會有幾十 甚至幾百種方法重組

The human flu virus could pick up a bird flu hemagglutinin

人類嘅流感病毒 會取得鳥類流感嘅血凝素

that’s never infected humans before.

而呢啲血凝素 可以從未感染過人類

This is called antigenic shift,

呢種叫做抗原轉移

and if you get infected by this version of influenza,

如果你感染到呢種流感

none of the antibodies against Napoleon's head are going to help you.

冇任何一種對付 拿破崙頭像嘅抗體幫到你

Antigenically shifted viruses have the potential

抗原轉變嘅病毒

to infect many people very quickly,

有潛力快速噉感染許多人

causing epidemics and sometimes pandemics.

造成大流行甚至疫情

A truly universal flu vaccine would be able to protect

真正通用嘅流感疫苗 會係能夠保護

against current flu strains and future drifted or shifted strains.

對抗當前嘅流感病毒株 同未來嘅漂移或者轉移嘅壓力

But how do we design a vaccine against a strain that doesn’t exist yet?

但我哋如何設計疫苗 對抗尚不存在嘅壓力呢？

We look to the past.

我哋回顧過去

There are key parts of hemagglutinin that haven’t changed much over time

血凝素有幾個關鍵部分 隨著時間推移並沒有太大變化

and are probably critical to infect human cells;

並且可能關鍵係 感染人體嘅細胞

these “conserved regions” could be promising targets for universal vaccines.

呢啲「保護區」可能 就係通用疫苗嘅希望目標

But there's a problem that's hindered classical vaccine production.

但有一個問題阻礙咗 經典疫苗嘅產生

Many conserved regions are in the neck,

許多保守區域位都喺頸部

and it’s tough to get the immune system to react to the neck.

而且好難令免疫系統 對頸部作出反應

Also, because influenza-like viruses have been around

同埋，因為流感類病毒一直存在

for hundreds of millions of years,

過億萬年，

there may not be a single region that’s common across all species

可能冇一個地區 係有所有流感病毒

and subtypes of influenza.

和流感亞型。

But there’s promising science in development.

但係有前途嘅科學喺度發展緊

Remember this?

仲記唔記得呢樣嘢？

This is a protein called ferritin;

呢個係叫做鐵蛋白嘅蛋白質

Its normal purpose is to store and move iron.

佢嘅正常目的 係儲存同移動鐵分子

But it’s also the rough size and shape of a small virus.

但佢亦都係一種小病毒 粗略嘅尺寸同形狀

And if you attach viral proteins to it, like this,

如果將病毒蛋白 附著喺上面，好似噉樣

you’d have something that looks, to an immune system, like a virus—

睇起來，對免疫系統來講 就好似病毒噉樣

but would be completely harmless and very engineerable.

但係完全無害 仲可具體工程化

Recently, scientists engineered a ferritin nanoparticle

最近，科學家設計咗 鐵蛋白奈米顆粒

to present 8 identical copies of the neck region of an H1 flu virus.

出示8份相同H1 流感病毒嘅副本喺頸部區域

They vaccinated mice with the nanoparticle,

加埋納米粒子喺疫苗 畀小鼠接種

then injected them with a lethal dose of a completely different subtype,

然後給他們注射致命劑量 完全不同的流感亞型

H5N1.

H5N1。

All the vaccinated mice lived; all the unvaccinated ones died.

所有接種疫苗嘅小鼠仍然生存 但所有未接種疫苗嘅人都就死咗

Going one step beyond that,

更進一步

there may be conserved regions that we could take advantage of

可能有啲保育區 我們可以利用

across different-but-related virus species—

跨越唔同但相關嘅病毒種類——

like SARS-CoV-2, MERS,

好似 SARS-CoV-2、MERS

and a few coronaviruses which cause some common colds.

同幾種冠狀病毒 都會導致一啲普通感冒

Over the past few decades,

過去幾十年度

a different part of the immune system has come into clearer focus.

免疫系統嘅不同部分 已成為更加清晰嘅焦點

Instead of antibodies, this part of the immune system

代替抗體， 免疫系統嘅呢一部分

uses a vast array of T cells that kill, for example,

使用大量嘅 T 細胞來殺死， 例如，

cells that have been infected by a virus.

被病毒感染嘅細胞

Vaccines that train this part of the immune system,

訓練呢個免疫系統部分嘅疫苗

in addition to the antibody response, could provide broader protection.

除咗抗體反應之外 可以提供更廣泛嘅保護

A universal flu vaccine would be a monumental achievement in public health.

通用嘅流感疫苗 將會是公共衛生領域嘅巨大成就

A fully universal vaccine against all infectious disease is— for the moment—

針對所有人完全通用 傳染病嘅疫苗——目前——

squarely in the realm of science fiction,

完全屬於科幻小說嘅範疇

partially because we have no idea how our immune system would react

部分原因係我哋唔知道 免疫系統會點樣反應

if we tried to train it against hundreds of different diseases at the same time.

如果我哋嘗試訓練佢 對抗數百種唔同嘅疾病。

Probably not well.

可能唔係幾好。

But that doesn’t mean it’s impossible.

但唔係無可能嘅

Look at where medicine is today compared to where it was two centuries ago.

睇下今天嘅醫學 比較返兩世紀前嘅處境

Who knows what it’ll look like in another 50 or 100 years—

邊個知道再過 50 年 或者 100 年佢會係點樣樣——

maybe some future groundbreaking technology

也許未來會有一啲突破性 嘅進展科技

will bring truly universal vaccines within our grasp.

將真正通用嘅疫苗 帶入我哋掌握之中