Every living being needs to fight off other living beings that want to feast on them.​

所以在多細胞生物經過了數億年的演化後， 也衍生出了保護自己的方法

Every living being needs to fight off other living beings that want to feast on them.​

現今，人類擁有複雜的防禦系統

So as multicellular life evolved over billions of years, it came up with ways to defend itself.​

像是物理屏障(皮膚)、防禦細胞(巨噬細胞)， 以及武器生產工廠(B細胞)

So as multicellular life evolved over billions of years, it came up with ways to defend itself.​

其中一個我們身體裡 但大多都還不太瞭解的防禦系統:

So as multicellular life evolved over billions of years, it came up with ways to defend itself.​

補體系統

Today humans have a sophisticated defense network,​

它已經演化超過7億年， 也是超過30種不同蛋白質的武裝軍隊

Today humans have a sophisticated defense network,​

他們合作跳起一支複雜而優雅的舞步， 來阻止外來入侵者

Today humans have a sophisticated defense network,​

總而言之，現在大約有1千5百萬兆的補體蛋白 充斥在你全身上下的液體當中

like physical barriers, defense cells, and weapons factories.​

指引他們的沒有別的，全是化學

like physical barriers, defense cells, and weapons factories.​

這些蛋白質是我們用來對抗入侵者的武器中 最有效的其中一種

like physical barriers, defense cells, and weapons factories.​

免疫系統中的許多部份， 都只是用來活化補體系統的工具

But one of the most important defenses of our body is largely unknown:​

但他同時也充滿危險性

But one of the most important defenses of our body is largely unknown:​

想像一下，在你的血液中，有數兆個小炸彈 而他們隨時都有可能會爆炸

But one of the most important defenses of our body is largely unknown:​

因此，我們的細胞用多種機制來防止補體意外的攻擊

The Complement System​

好，那他們又有什麼功用?又是為什麼讓他們看起來這麼危險呢?

The Complement System​

簡而言之，補體系統有3樣工作。

The Complement System​

它會癱瘓敵人， 它會啟動免疫系統 它會在菌體上鑿洞直到它們死亡

It evolved over 700 million years ago and is an army of over 30 different proteins​

但是，要怎麼做?

It evolved over 700 million years ago and is an army of over 30 different proteins​

畢竟，這些無意識的蛋白質們會隨意飄動 沒有任何目的或方向

It evolved over 700 million years ago and is an army of over 30 different proteins​

實際上這算是一種戰略

that work together in a complex and elegant dance to stop intruders.​

隨意飄動的補體蛋白處於一種被動狀態

that work together in a complex and elegant dance to stop intruders.​

他們沒有任何影響力，直到他們被啟動 並且改變他們的形狀

that work together in a complex and elegant dance to stop intruders.​

在蛋白質的世界裡，你的形狀決定了什麼事情你可以做 什麼事情你不能做

All in all, about 15 quintillion of them are saturating every fluid in your body right now.​

因為形狀決定了可以互動的對象和方式

All in all, about 15 quintillion of them are saturating every fluid in your body right now.​

舉例來說，處於被動狀態的形狀下 你可能不會有任何的功能

All in all, about 15 quintillion of them are saturating every fluid in your body right now.​

然而，在你啟動的狀態下 你可能可以啟動其他蛋白質的形體

Guided by nothing but chemistry,​

藉此啟動他們，讓他們也可以啟動其他蛋白

Guided by nothing but chemistry,​

像這樣的串聯反應的機制可以快速地擴散出去

Guided by nothing but chemistry,​

想像一下這些補體蛋白就像一組互相放的很近的火柴

these proteins are one of the most effective weapons we have against invaders.​

一但其中一根火柴起火了 它會立即點燃其他根靠近它的火柴

these proteins are one of the most effective weapons we have against invaders.​

當它點燃的越多，突然間你就有可以有一團大火

these proteins are one of the most effective weapons we have against invaders.​

要列舉出補體系統的實際機制和樣貌會很複雜

Many other parts of the immune system are just tools to activate the Complement System.​

所以我們在此會簡化它們

Many other parts of the immune system are just tools to activate the Complement System.​

現在，想像一下你不小心劃傷了自己 有一群細菌從傷口的位置

Many other parts of the immune system are just tools to activate the Complement System.​

進入了周圍組織

But it's also really dangerous.​

補體系統C3 就會開始進行攻擊

But it's also really dangerous.​

C3就會是最開始的火花，可以點燃我們的火團

But it's also really dangerous.​

要點燃他，C3必須得要從被動狀態切換成啟動狀態

Imagine having trillions of little bombs inside your blood that could go off at any moment.​

要解釋它如何啟動是有點複雜 在這邊當成它是隨機的

Imagine having trillions of little bombs inside your blood that could go off at any moment.​

通過其他被細菌啟動的補體蛋白，或從抗體啟動的

Imagine having trillions of little bombs inside your blood that could go off at any moment.​

現在你要知道C3已經分裂成2個比較小的蛋白質

So our cells use numerous mechanisms to prevent​ ​complement from accidentally attacking ​​them​.​

已經被啟動的C3a和C3b

So our cells use numerous mechanisms to prevent​ ​complement from accidentally attacking ​​them​.​

其中一個部分，蛋白質C3b會像一個追蹤導彈一樣 尋找特定的細菌、真菌和病毒

So our cells use numerous mechanisms to prevent​ ​complement from accidentally attacking ​​them​.​

它只有不到一秒鐘的時間來找到它的敵人 不然它就會被水分子中和掉

Okay, what exactly does it do and what makes it so dangerous?​

假設C3b找到一個目標 它會將自己緊緊的固定在敵人的表面且不會鬆開

Okay, what exactly does it do and what makes it so dangerous?​

通過這樣做以後，蛋白質會再次變換形狀

Okay, what exactly does it do and what makes it so dangerous?​

藉由這個新的形狀，它現在可以與其它蛋白質做連結 並且在啟動比較小的串聯反應

In a nutshell, The Complement System does three things:​

經過多次變換它的形狀，來增加其他蛋白質在它身上

In a nutshell, The Complement System does three things:​

最後，它會將它自己轉變成一個名為C3 Convertase 的招收平台

In a nutshell, The Complement System does three things:​

這個專門的平台，可以將更多C3蛋白質轉換 並且重新開始整個循環

it cripples enemies, it activates the immune system, and it rips holes in things until they die.​

一個增幅循環開始了

it cripples enemies, it activates the immune system, and it rips holes in things until they die.​

不用多久，成千的蛋白質就包覆著細菌了

it cripples enemies, it activates the immune system, and it rips holes in things until they die.​

對菌體來說，這對它非常的不利

But, how?​

它們會削弱這個菌體，讓他們無法求助或是緩慢它們

But, how?​

想像被好幾千隻的蒼蠅包覆著的感覺

But, how?​

還不只這些呢!

After all, these are mindless proteins randomly drifting around without will or direction.​

你還記得C3的另一部分嗎? C3a蛋白質

After all, these are mindless proteins randomly drifting around without will or direction.​

C3a就像是一個求救信標

After all, these are mindless proteins randomly drifting around without will or direction.​

成千上萬的湧出戰場，引起大量的注意

Well, this is actually part of the strategy.​

被動的免疫細胞注意到這些C3a以後

Well, this is actually part of the strategy.​

會從休眠狀態甦醒過來 並且跟著蛋白質的軌跡到達感染的部位

Well, this is actually part of the strategy.​

當接觸到越多的求救信標蛋白，它們就會越具有侵略性

Complement proteins float around in a sort-of passive mode.​

用這種方式 補體蛋白可以正確的引導他們到最需要增援的地方

Complement proteins float around in a sort-of passive mode.​

到現在，補體蛋白已經成功求救並拖住入侵者了

Complement proteins float around in a sort-of passive mode.​

現在開始，它們要開始積極地幫助到殺死敵人

They do nothing, until they get activated and change their shape.​

第一批到達戰場的免疫細胞是吞噬細胞

They do nothing, until they get activated and change their shape.​

這代表著，吞噬細胞會把你整個吞掉 把你關在一個小監牢裡，再用酸殺掉你

They do nothing, until they get activated and change their shape.​

但是要吞掉一個敵人，它們必須要先抓到敵人才行

In the world of proteins, your shape determines what you can and cannot do.​

這不太簡單，因為細菌不喜歡被抓住，而且它們滑滑的

In the world of proteins, your shape determines what you can and cannot do.​

但是現在，補體蛋白已經將自己固定在細菌身上

In the world of proteins, your shape determines what you can and cannot do.​

當作一個像是膠水一樣 讓免疫細胞可以輕易抓住它們的敵人

Because shape determines what you can interact with and in what way.​

更好的是

Because shape determines what you can interact with and in what way.​

想像一下! 你又一次被一堆蒼蠅給包覆著

Because shape determines what you can interact with and in what way.​

現在，這些蒼蠅變成了黃蜂

For example, in your passive shape you might do nothing.​

另一個串聯反應要開始了

For example, in your passive shape you might do nothing.​

另一個串聯反應要開始了

For example, in your passive shape you might do nothing.​

在這個菌體的表面，C3 Convertase 再次地變換它的形狀

In your active shape, however, you might, for example, change the shape of other proteins​

並且開始招募新的蛋白質

In your active shape, however, you might, for example, change the shape of other proteins​

他們會變成一個比較大的結構: 膜攻擊複合物

In your active shape, however, you might, for example, change the shape of other proteins​

一片一片的，新的蛋白質(C9)將長得像矛的自己扎進細菌膜裡

activating them so they can activate others.​

直到他們撐開出無法修復的大洞

activating them so they can activate others.​

流體衝入菌體以後，他們的內部也就隨之溢出

activating them so they can activate others.​

如同流血致死

Mechanisms like this one can start cascades that spread very quickly.​

剩下的菌體也因為被補體騷擾而分心，甚至重傷

Mechanisms like this one can start cascades that spread very quickly.​

馬上就被到場的免疫細胞給解決掉了

Mechanisms like this one can start cascades that spread very quickly.​

在入侵變得更危險之前，這次的攻擊行動就已經被剷除了

Imagine the complement proteins as being like millions of matches very close together.​

你可能都還沒有注意到

Imagine the complement proteins as being like millions of matches very close together.​

細菌也只是很不喜歡補體而已

Imagine the complement proteins as being like millions of matches very close together.​

實際上補體對抗病毒更為有效

Once one catches fire, it ignites the ones around it.​

病毒有一個大問題，它們必須得要在細胞之間移動

Once one catches fire, it ignites the ones around it.​

病毒在細胞外基本上以只能祈禱希望以極小的機率撞到且感染細胞

Once one catches fire, it ignites the ones around it.​

在這裡，他們是完全沒有防禦的

They ignite more and suddenly you have a big fire.​

在此，補體就可以直接攔截並削弱他們

They ignite more and suddenly you have a big fire.​

讓它們變得無害並引導免疫系統來吞噬它們

They ignite more and suddenly you have a big fire.​

如果沒有補體，病毒感染會變得非常致命

To show the actual mechanisms of The Complement System is a tad complicated and overwhelming.​

等等，如果我們有這麼有效的武器 為什麼我們還會生病?

To show the actual mechanisms of The Complement System is a tad complicated and overwhelming.​

問題是在戰爭之中，雙方都會互相適應

To show the actual mechanisms of The Complement System is a tad complicated and overwhelming.​

舉例來說，當牛痘病毒感染了一個細胞時

So, we'll simplify here.​

它會強迫細胞制造出一種蛋白質來關閉補體蛋白

So, we'll simplify here.​

用這種方式，病毒能夠在被感染的細胞周圍 形成一個安全區

So, we'll simplify here.​

當病毒殺死這個細胞以後 可以有更高的機率感染附近其他的健康細胞

Now, let's imagine you cut yourself and a bunch of bacteria enter the wound​

或是像其他的細菌，舉例來說，它可以從血液裡抓取一些特定的分子，不觸發補體系統

Now, let's imagine you cut yourself and a bunch of bacteria enter the wound​

進而達成隱形的效果

Now, let's imagine you cut yourself and a bunch of bacteria enter the wound​

所以補體系統，是非常非常重要的

and make it into the surrounding tissue.​

但是它在我們美麗並且複雜的免疫系統組織之中 只是其中一員

and make it into the surrounding tissue.​

這是一個無意識的小東東 卻可以一起做一些聰明合作的漂亮例子

and make it into the surrounding tissue.​

這個影片是由 你 來贊助的

Our complement attack begins with C3.​

沒有你的直接支持，這個頻道就不會存在

Our complement attack begins with C3.​

而且非常難形容我們對此的感激之情

Our complement attack begins with C3.​

在2019年 每一部kurzgesagt的影片至少要花1200小時來製造

C3 is the first match, the initial spark that will start our fire.​

我們要花上好幾個月來做研究及 寫腳本並向專家們確認

C3 is the first match, the initial spark that will start our fire.​

並且製做一張一張的插圖、製成動畫 再加入原創的音樂

C3 is the first match, the initial spark that will start our fire.​

依靠著贊助商

And to do that, C3 needs to switch from passive to active.​

你們在Patreon上的支持還有販賣一些周邊 才有可以達成

And to do that, C3 needs to switch from passive to active.​

像是我們製作了補體系統的張海報和明信片

And to do that, C3 needs to switch from passive to active.​

如果你有興趣，想要支持我們

How this happens is complex, but let's just say it can happen randomly​

你可以觀看我們的影片 訂閱Patreon並且製作一隻專屬於你的小鳥鳥

How this happens is complex, but let's just say it can happen randomly​

或是購買我們的日曆或海報

How this happens is complex, but let's just say it can happen randomly​

製作最好的影片

through other complement proteins that bind to enemies or through antibodies.​

和讓科學更靠近我們的生活 是kurzgesagt的宗旨

through other complement proteins that bind to enemies or through antibodies.​

謝謝你讓這一切變得可能

through other complement proteins that bind to enemies or through antibodies.​

All you really need to know is that C3 breaks into two smaller proteins,​

All you really need to know is that C3 breaks into two smaller proteins,​

All you really need to know is that C3 breaks into two smaller proteins,​

C3a and C3b, that are now activated.​

C3a and C3b, that are now activated.​

C3a and C3b, that are now activated.​

One of these parts, the C3b protein, is like a seeker missile specialized in bacteria, fungi, and viruses.​

One of these parts, the C3b protein, is like a seeker missile specialized in bacteria, fungi, and viruses.​

One of these parts, the C3b protein, is like a seeker missile specialized in bacteria, fungi, and viruses.​

It has a fraction of a second to find a victim or it will be neutralized by water molecules.​

It has a fraction of a second to find a victim or it will be neutralized by water molecules.​

It has a fraction of a second to find a victim or it will be neutralized by water molecules.​

If C3b does find a target, it anchors itself very tightly to its surface and doesn't let go.​

If C3b does find a target, it anchors itself very tightly to its surface and doesn't let go.​

If C3b does find a target, it anchors itself very tightly to its surface and doesn't let go.​

By doing so, the protein changes its shape again.​

By doing so, the protein changes its shape again.​

By doing so, the protein changes its shape again.​

In its new shape, it's now able to grab other proteins and start a small cascade,​

In its new shape, it's now able to grab other proteins and start a small cascade,​

In its new shape, it's now able to grab other proteins and start a small cascade,​

changing its shape multiple times, adding other complement proteins to itself.​

changing its shape multiple times, adding other complement proteins to itself.​

changing its shape multiple times, adding other complement proteins to itself.​

Finally, it transforms itself into a recruiting platform known as C3 Convertase.​

Finally, it transforms itself into a recruiting platform known as C3 Convertase.​

Finally, it transforms itself into a recruiting platform known as C3 Convertase.​

This platform is an expert at activating more C3 proteins that start the whole cycle anew.​

This platform is an expert at activating more C3 proteins that start the whole cycle anew.​

This platform is an expert at activating more C3 proteins that start the whole cycle anew.​

An amplification loop begins.​

An amplification loop begins.​

An amplification loop begins.​

Soon, thousands of proteins cover the bacteria.​

Soon, thousands of proteins cover the bacteria.​

Soon, thousands of proteins cover the bacteria.​

For the bacteria, this is very bad.​

For the bacteria, this is very bad.​

For the bacteria, this is very bad.​

It can cripple the bacteria and make them helpless, or slow them down.​

It can cripple the bacteria and make them helpless, or slow them down.​

It can cripple the bacteria and make them helpless, or slow them down.​

Imagine being covered by thousands of flies.​

Imagine being covered by thousands of flies.​

Imagine being covered by thousands of flies.​

But, there's more.​

But, there's more.​

But, there's more.​

Do you remember the other part of C3—the C3a protein?​

Do you remember the other part of C3—the C3a protein?​

Do you remember the other part of C3—the C3a protein?​

C3a is like a distress beacon.​

C3a is like a distress beacon.​

C3a is like a distress beacon.​

Thousands of them flood away from the site of battle screaming for attention.​

Thousands of them flood away from the site of battle screaming for attention.​

Thousands of them flood away from the site of battle screaming for attention.​

Passive immune cells notice the C3a proteins,​

Passive immune cells notice the C3a proteins,​

Passive immune cells notice the C3a proteins,​

and awaken from their slumber to follow the protein tracks to the site of infection.​

and awaken from their slumber to follow the protein tracks to the site of infection.​

and awaken from their slumber to follow the protein tracks to the site of infection.​

The more alarm proteins they encounter, the more aggressive they get.​

The more alarm proteins they encounter, the more aggressive they get.​

The more alarm proteins they encounter, the more aggressive they get.​

This way, complement guides reinforcements exactly to the place where they're needed the most.​

This way, complement guides reinforcements exactly to the place where they're needed the most.​

This way, complement guides reinforcements exactly to the place where they're needed the most.​

So far, the complement has slowed down the invaders and called for help.​

So far, the complement has slowed down the invaders and called for help.​

So far, the complement has slowed down the invaders and called for help.​

Now, it's beginning to actively help to kill the enemy.​

Now, it's beginning to actively help to kill the enemy.​

Now, it's beginning to actively help to kill the enemy.​

The first immune cells to arrive at the battlefield are ​​phagocytes​.​