免疫系统全解 I – 细菌感染：英语精读讲义

Every second of your life you are under attack. 習語

在你生命中的每一秒，你都在受到攻击。

Billions of bacteria, viruses, and fungi

数以十亿计的细菌、病毒和真菌

are trying to make you their home. 習語

正试图把你的身体变成它们的家。

So our bodies have developed a super complex little army

因此，我们的身体进化出了一支超级复杂的小型军队，

with guards, soldiers, intelligence, weapons factories,

里面有守卫、士兵、情报人员、武器工厂

and communicators

和通讯员，

to protect you from, uh, well, dying.

来保护你免于……呃，死亡。

For this video,

在本期视频中，

let's assume the immune system has 12 different jobs. 表達脈絡

让我们假设免疫系统有12种不同的工作。

For example, kill enemies, communicate, etc.

例如，杀死敌人、通讯等等。

And it has 21 different cells and two protein forces.

它拥有21种不同的细胞和两支蛋白质部队。

These cells have up to four different jobs.

这些细胞最多有四种不同的工作。

Let's assign them.

让我们为它们分配任务。

Here are the interactions.

这些是它们之间的互动。

Now, let's make this understandable.

现在，让这一切变得好懂一些。

First of all, let's add colors to the jobs.

首先，我们为这些工作标上颜色。

Now, let's illustrate the cells.

现在，来图解这些细胞。

The central color represents the main job of the cell, 語法

中间的颜色代表细胞的主要工作，

while the surrounding ones represent secondary duties.

周围的颜色代表次要职责。

Now, the immune system looks like this.

现在，免疫系统看起来像这样。

Now, the interactions.

接下来，看看互动过程。

Isn't this complexity just awesome?

这种复杂性是不是很棒？

For this video, we will only talk about these cells and ignore the rest. 表達脈絡

在本期视频中，我们将只讨论这些细胞，忽略其他部分。

So, what happens in the case of an infection? 短語搭配

那么，在感染的情况下会发生什么？

It's a beautiful day

这是一个美好的一天，

when suddenly a wild rusty nail appears

突然出现了一根野生的生锈铁钉，

and you cut yourself.

你割伤了自己。

The first barrier of the immune system is breached, 用詞

免疫系统的第一道防线被突破了，

your skin.

也就是你的皮肤。

Nearby bacteria seize on the opportunity 短語搭配

附近的细菌抓住机会，

and enter your wound.

进入你的伤口。

They start using up the body's resources 短語動詞

它们开始消耗身体的资源，

and double their numbers about every 20 minutes. 短語搭配

数量大约每20分钟翻一番。

At first, they fly under the radar, 習語

起初，它们悄悄潜伏，

but when a certain bacteria population is reached, 語法

但当细菌达到一定的数量时，

they change their behavior and start to damage the body

它们会改变行为并开始破坏身体，

by changing the environment around them.

方式是改变它们周围的环境。

The immune system has to stop them as fast as possible. 短語搭配

免疫系统必须尽快阻止它们。

First of all, your guard cells,

首先，你的守卫细胞，

known as macrophages, intervene. 語法

即巨噬细胞，开始介入。

They are huge cells that guard every border region of the body.

它们是守护身体每个边界区域的巨型细胞。

Most of the time, they alone can suffocate an attack

大多数时候，仅靠它们就能扼杀一次攻击，

because they can devour up to 100 intruders each.

因为它们每个最多能吞噬100个入侵者。

They swallow the intruder whole and trap it inside a membrane. 短語搭配

它们将入侵者整个吞下并困在膜内。

Then the enemy gets broken down by enzymes and is killed. 短語動詞

然后敌人被酶分解并被杀死。

On top of that, they cause inflammation 表達脈絡

此外，它们还会引发炎症，

by ordering the blood vessels to release water into the battlefield,

通过命令血管向战场释放水分，

so fighting becomes easier.

从而让战斗变得更容易。

You notice this as a very mild swelling.

你会感觉这是非常轻微的肿胀。

When the macrophages fight for too long,

当巨噬细胞战斗时间过长时，

they call in heavy backup 短語動詞

它们会呼叫重火力增援，

by releasing messenger proteins

通过释放信使蛋白质，

that communicate location and urgency.

来传递位置和紧急情况。

Neutrophils leave their patrol routes in the blood

中性粒细胞离开血液中的巡逻路线，

and move to the battlefield.

移动到战场。

The neutrophils fight so furiously 語法

中性粒细胞战斗得极其猛烈，

that they kill healthy cells in the process.

以至于它们在这个过程中也会杀死健康细胞。

On top of that,

此外，

they generate barriers

它们会产生屏障，

that trap and kill the bacteria.

将细菌困住并杀死。

They are indeed so deadly

它们确实非常致命，

that they evolved to commit suicide after 5 days

以至于它们进化到在5天后自杀，

to prevent them from causing too much damage. 語法

以防止它们造成太大的伤害。

If this is not enough to stop the invasion,

如果这还不足以阻止入侵，

the brain of the immune system kicks in. 短語動詞

免疫系统的大脑就会启动。

The dendritic cell gets active.

树突状细胞开始活跃。

It reacts to the signals of the soldiers 短語搭配

它对士兵的信号做出反应，

and starts collecting samples from the enemies.

并开始从敌人那里收集样本。

They rip them into pieces 短語動詞

它们把敌人撕碎，

and present the parts on their outer layer.

并将这些部分展示在自己的外层。

Now,

现在，

the dendritic cell makes a crucial decision. 短語搭配

树突状细胞做出了一个关键决定。

Should they call for antiviral forces 短語動詞

它们应该呼叫抗病毒部队

that eradicate infected body cells

去根除被感染的身体细胞，

or an army of bacteria killers?

还是呼叫一支细菌杀手军队？

In this case, 表達脈絡

在这种情况下，

antibacterial forces are necessary.

抗菌部队是必要的。

It then travels to the closest lymph node

然后它会前往最近的淋巴结，

in about a day.

大约需要一天的时间。

Here,

在这里，

billions of helper and killer T cells

数以十亿计的辅助性T细胞和杀手T细胞

are waiting to be activated.

正在等待被激活。

When T cells are born,

当T细胞诞生时，

they go through a difficult and complicated training process 短語搭配

它们要经历一个艰难而复杂的训练过程，

and only a quarter survives.

只有四分之一能存活下来。

The surviving cells are equipped with a specific setup. 短語搭配

幸存的细胞配备了特定的配置。

And the dendritic cell is on its way

树突状细胞正在路上，

looking for a helper T cell

寻找一个辅助性T细胞，

with a setup that's just right.

一个配置正好合适的T细胞。

It's looking for a helper T cell

它寻找的辅助性T细胞

that combine to the parts of the intruders,

能够与入侵者的部分相结合，

which the dendritic cell has presented on its membrane.

也就是树突状细胞在其膜上展示的那些。

When it finally finds one,

当它最终找到这样一个细胞时，

a chain reaction takes place. 短語搭配

连锁反应发生了。

The helper T cell is activated.

辅助性T细胞被激活。

It quickly duplicates thousands of times.

它迅速自我复制数千次。

Some become memory T cells

一些变成了记忆T细胞，

that stay in the lymph node

留在淋巴结中，

and will make you practically immune against this enemy.

让你实际上对这种敌人免疫。

Some travel to the field of battle to help out. 短語動詞

另一些前往战场帮忙。

And the third group goes on to travel to the center of the lymph node 表達脈絡

第三组则前往淋巴结中心，

to activate a very powerful weapons factory.

去激活一个非常强大的武器工厂。

Like the T cells,

就像T细胞一样，

they're born with a specific setup.

它们（B细胞）天生带有特定的配置。

And when a B cell and a T cell with the same setup meet,

当具有相同配置的B细胞和T细胞相遇时，

hell breaks loose. 習語

战斗瞬间爆发。

The B cell duplicates rapidly

B细胞迅速复制，

and starts producing millions of little weapons.

并开始生产数以百万计的小武器。

They work so hard 語法

它们工作得如此拼命，

that they would literally die from exhaustion very fast.

以至于很快就会字面意义上地死于精疲力竭。

Here,

在这里，

helper T cells play another important role. 短語搭配

辅助性T细胞发挥了另一个重要作用。

They stimulate the hardworking factories

它们刺激这些努力工作的工厂，

and tell them,

并告诉它们：

"Don't die yet. 語氣意圖

"先别死。

We still need you.

我们还需要你们。

Keep going."

继续坚持。"

This also ensures that the factories die 語法

这也确保了工厂会在感染结束后死亡，

if the infection is over,

如果感染已经结束，

so the body doesn't waste energy or hurt itself.

这样身体就不会浪费能量或伤害自己。

But what is produced by the B cells?

但是B细胞生产的是什么呢？

You've heard of them, 短語搭配

你当然听说过它们，

of course, antibodies.

当然是抗体。

Little proteins that are engineered

被专门设计用来

to bind to the surface of the specific intruder. 用詞

结合在特定入侵者表面的小蛋白质。

There are even different kinds of antibodies

甚至有不同种类的抗体，

that have slightly different jobs.

有着略微不同的工作。

The helper T cells tell the plasma cells

辅助性T细胞告诉浆细胞

which type is needed the most in this particular invasion. 語法

在这次特定的入侵中最需要哪种类型。

Millions of them flood the blood

数以百万计的抗体涌入血液，

and saturate the body.

布满整个身体。

Meanwhile, at the site of infection, 表達脈絡

与此同时，在感染部位，

the situation is getting dire. 用詞

情况变得越来越危急。

The intruders have multiplied in number

入侵者的数量成倍增加，

and start hurting the body.

并开始伤害身体。

Guard and attack cells fight hard,

守卫和攻击细胞奋力战斗，

but also die in the process.

但也在战斗中死亡。

Helper T cells support them

辅助性T细胞支援它们，

by ordering them to be more aggressive 語法

命令它们更具攻击性

and to stay alive longer.

并尽可能活得更久。

But without help, 語法

但如果没有帮助，

they can't overwhelm the bacteria.

它们无法战胜细菌。

But now,

但是现在，

the second line of defense arrives. 習語

第二道防线到达了。

Billions of antibodies flood the battlefield

数十亿个抗体淹没了战场，

and disable lots of the intruders,

使许多入侵者瘫痪，

rendering them helpless 語法

让它们失去抵抗能力

or killing them in the process.

或在过程中杀死它们。

They also stun the bacteria

它们还能击晕细菌，

and make them an easy target. 語法

让它们成为容易被攻击的目标。

Their back is built to connect to killer cells,

它们的尾部被设计为能与杀手细胞相连，

so they can connect and kill the enemy more easily.

这样它们就能更容易地连接并杀死敌人。

Macrophages are especially good at nomming up the bacteria,

巨噬细胞尤其擅长吞噬

which antibodies have attached to.

那些被抗体附着的细菌。

Now, the balance shifts. 表達脈絡

现在，战局发生了逆转。

In a team effort,

在团队合作下，

the infection is wiped out. 短語動詞

感染被消灭了。

At this point, 表達脈絡

此时，

millions of body cells have already died.

数百万个身体细胞已经死亡。

No big deal, 語氣意圖

没什么大不了的，

the losses are quickly replenished.

损失很快就能得到补充。

Most immune cells are now useless

绝大多数免疫细胞现在已经没用了，

and without the constant signals,

而且没有了持续的信号，

they commit suicide,

它们就会自杀，

so as not to waste any resources. 語法

以免浪费任何资源。

But some stay behind, 短語動詞

但有一些细胞留了下来，

the memory cells.

它们是记忆细胞。

If this enemy is encountered ever again in the future, 語法

如果将来再次遇到这个敌人，

they will be ready for it

它们会严阵以待，

and probably kill it before you even notice.

很可能在你察觉之前就把它杀死了。

This was a very, very simplified explanation

这只是对部分免疫系统运作的

of parts of the immune system at work. 短語搭配

一个非常、非常简化的解释。

Can you imagine how complex this system is?

你能想象这个系统有多复杂吗？

Even at this level,

即使在目前这个层面，

when we ignore so many players and all the chemistry?

当我们忽略了那么多参与者和所有化学反应时？

Life is awfully complicated,

生命复杂得令人敬畏，

but if we take the time to understand it, 語法

但如果我们花时间去了解它，

we'll encounter endless wonders

我们就会遇到无尽的奇迹

and great beauty.

和极致的美丽。

This bird has magical powers.

这只鸟拥有神奇的力量。

Let's see a demonstration.

让我们来看个示范。

Bring in the latest scientific research. 短語動詞

引入最新的科学研究。

Wow,

哇，

that's a lot of complicated stuff

这可全是关于免疫系统和它所有细胞的

about the immune system and all its cells.

复杂玩意儿。

How could someone possibly understand all of this?

一个人怎么可能搞懂所有这些？

Incredible.

真是不可思议。

This overview is delightful

这个概览非常有趣

and easy to grasp, 短語搭配

且通俗易懂，

but still scientifically accurate.

但依然科学严谨。

Let's make it a bit more difficult.

让我们稍微增加一点难度。

Can she make all of evolution visible at a glance? 習語

她能让人一眼看清整个进化过程吗？

This is brilliant.

太妙了。

You can clearly see the relationships between species

你可以清楚地看到物种之间的关系

and how they evolved.

以及它们是如何进化的。

And look at those illustrations.

看看这些插图。

These posters are ready to be shared with the world. 語法

这些海报已经准备好与世界分享了。

These very special pieces of Kurzgesagt

这些非常特别的 Kurzgesagt 作品

are now available on our shop

现在在我们的商店有售，

along with many other sciencey products,

还有许多其他充满科学气息的产品，

all researched with care 語法

每一件都经过精心研究

and created with love

并由拥有神奇力量的鸟儿们

by the birds with magical powers.

充满爱心地创作出来。

Every Kurzgesagt product you buy

你购买的每一件 Kurzgesagt 产品

directly funds another moment

都在直接资助我们

we get to spend working on our videos. 語法

能够花在制作视频上的下一刻。

Thank you so much for being a part of our story 語氣意圖

非常感谢你们成为我们故事的一部分，

and for making this channel possible.

并感谢你们让这个频道成为可能。