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免疫系统

Immune System: Innate and Adaptive Immunity Explained

Our body has a powerful army
我们体内有一支强大的军队
that protects it from various types of threats.
帮我们抵御种种威胁
These threats can come in the form of mechanical injuries,
这些威胁包括机械性损伤
the entry of germs,
细菌入侵
or the entry of other foreign particles like dust.
或是异物颗粒比如灰尘进入体内
This personal army is called the immune system.
这支私人军队叫做免疫系统
《科学ABC》
Every day, we encounter a huge number of bacteria,
每天我们都会遇到大量细菌
viruses and other disease-causing organisms.
病毒和其他致病的生物
However, we don’t fall ill every other day.
但是 我们不会每天都生病
which is due to our immune system-
这要归功于我们的免疫系统——
an army of cells that is always roaming our body,
一支时刻在我们体内巡逻的细胞军队
ready to ward off any attack.
准备抵御任何攻击
The immune system can be broadly divided into two parts
免疫系统大致可以分为两部分
innate and adaptive immunity.
固有免疫和适应性免疫
Innate immunity or non-specific immunity
固有免疫 或称非特异性免疫
is the body’s first natural defense to any intruder.
是身体对入侵者的第一道天然防线
This system doesn’t care what it’s killing.
这种免疫系统不关心消灭的是什么
Its primary goal is to prevent any intruder from entering the body,
它的首要目标是避免任何入侵者进入体内
and if it does enter,
一旦侵入体内
then the immune system neutralize this intruder.
那么免疫系统就会消灭入侵者
It doesn’t differentiate between one pathogen and another.
而且它不会一个一个区分病原体
The first component of this defensive system is your skin.
这个防御系统的第一部分就是你的皮肤
Any organism trying to get into the body is stopped by the skin,
它会阻止所有试图进入身体的生物
our largest organ, which covers us.
是我们最大的器官 覆盖在全身
Secondly, there is the mucous lining of all our organs.
其次 我们所有器官内壁都有粘膜
The sticky, viscous fluid traps any pathogens trying to get past it.
这些黏稠的黏液会阻止试图通过的病原体
These are the two physical barriers.
这是两道物理屏障
However, we also have chemical barriers,
然而我们还有化学屏障
such as the lysozyme in the eyes, or the acid in the stomach,
比如眼睛里的溶菌酶 还有胃里的胃酸
which kill pathogens trying to gain entry.
都会消灭想要入侵的病原体
The genitourinary tract and other places
泌尿生殖道和其他地方
have their own normal flora, or microbial community.
都有自己的正常菌群 或微生物群落
These compete with pathogens for space and food,
它们与病原体争夺空间和食物
and therefore also act as a barrier.
所以也起到了屏障的作用
The next line of defense is inflammation,
下一道防线是炎症
which is done by mast cells.
由肥大细胞引起
These cells are constantly searching for suspicious objects in the body.
这些细胞在体内不断地搜寻可疑物
When they find something, they release a signal in the form of histamine molecules.
找到后 它们会释放组胺分子作为信号
These alert the body,
这会让身体警觉
and blood is rushed to the problem area.
血液会迅速聚集到有问题的区域
This causes inflammation and also brings leukocytes, or white blood cells,
这会导致炎症 还会带来白血球 或称白细胞
which are soldiers in our body’s cellular army.
它们是我们体内细胞军团的士兵
Once they come, all hell breaks loose!
一旦到来 顿时乱作一团
Sometimes however, the intruder may not be germ,
但是有时入侵者可能不是细菌
but rather a harmless thing like a dust particle.
而是像灰尘之类的无害物
The body still causes a full immune reaction to this intruder,
人体还是会对它产生完全的免疫反应
which is how allergic reactions occur.
这就是产生过敏反应的原因
In the fortress of our body, the leukocytes are VIPs.
在我们的身体堡垒中 白血球是VIP
They have an all-access pass to the body,
它们拥有通往全身的权限
except, of course, to the brain and spinal cord.
当然 除了大脑和脊髓
Our leukocytes come in many types.
白血球有很多种类
Those that belong to the innate system are the phagocytes.
那些属于固有免疫系统的是吞噬细胞
These cells can either patrol your body, like the neutrophils,
这些细胞能在体内巡逻 比如中性粒细胞
or they can stay in certain places and wait for their cue.
也能待在特定的位置等待指示
Neutrophils are the most abundant cells.
中性粒细胞是体内数量最多的吞噬细胞
They patrol the body and can therefore get to a breach site very quickly.
它们在体内巡逻 以便尽快到达伤口
These cellular soldiers kill the infectious cell and then die,
这些细胞士兵杀死感染细胞后死亡
which leads to pus formation.
这导致了脓液的形成
There are also the big bad wolves, or the macrophages.
还有一些狠角色 叫做巨噬细胞
These cells are like hungry, ravenous monsters
这些细胞就如饥饿贪婪的怪物一般
who simply engulf unwanted pathogens.
简单粗暴地吞下有害病原体
Instead of roaming freely in our blood,
它们会在特定区域聚集
they are collected in certain places.
而不会在血液中自由巡逻
These cells can consume about 100 pathogens before they die,
这些细胞在死前可以消灭大约100个病原体
but they can also detect our own cells that have gone rogue,
但它们也可以识别病变的细胞
such as cancer cells, and kill them too.
例如癌细胞 并消灭它们
Beyond that, we also have the Natural Killer Cells.
此外 我们还有自然杀伤细胞(NKC)
These cells can efficiently detect when our own cells have gone rogue,
这些细胞可以高效地识别病变的
or are infected with, say, a virus.
或被感染的细胞 比如被病毒感染
NKCs detect a protein produced by normal cells,
NKC会识别正常细胞合成的一种蛋白质
called the Major Histocompatibility Complex or MHC.
叫做主要组织相容性复合体或MHC
Basically, whenever a cell isn’t normal,
一般来说 细胞一旦发生异常
it stops producing this protein.
就会停止合成这种蛋白质
The NKCs move around constantly,
NKC会不断地移动
checking our cells for this type of deficiency,
来检查细胞是否有这种蛋白质缺失
and when they find an abnormal cell,
在找到异常细胞后
they simply bind to it and release chemicals that will destroy it.
就会与之结合 并释放化学物质将其破坏
The last cells of our innate immune system are the dendritic cells.
固有免疫中最后一类细胞是树突状细胞
These are found in places that come in contact with the outside environment,
它们分布于与外界环境相连通的地方
such as the nose, lungs, etc.
比如鼻子 肺等
They are the link between our innate and adaptive immune systems.
它们是固有免疫与适应性免疫系统之间的纽带
They eat a pathogen,
它们吞噬病原体
and then carry information about it to our adaptive immune system cells.
然后给适应性免疫系统的细胞带去相关的信息
This information is produced and shared in the form of antigens.
这个信息以抗原的形式产生并共享
Antigens are the traces that pathogens leave around.
抗原是病原体留下的痕迹
They are molecules found on the surface on pathogens
它们是位于病原体表面的分子
that can be detected by our adaptive immune system for recognition.
可以被适应性免疫系统发现以识别
The dendritic cells pass on this information to our T cells.
树突状细胞会把这些信息传递给T细胞
However, macrophages can also perform this function.
然而 巨噬细胞也能起到这个作用
Now, there is also the adaptive or acquired immune system.
此外 我们还有适应性 或称获得性免疫系统
This system is more efficient,
这个系统更加高效
as it can differentiate between different types of pathogens.
因为它可以分辨不同类型的病原体
It has 2 main components – T lymphocytes and B lymphocytes.
它主要有两部分 T淋巴细胞与B淋巴细胞
T-cells come into play when an infection has already occurred,
T细胞在感染发生后才会介入
thus bringing about the cell-mediated immune response.
从而引起细胞免疫应答
B-cells join the fight when the pathogens have entered,
B细胞会在病原体进入人体
but haven’t yet caused any disease.
但还未引起疾病时介入
This is called the humoral immune response.
这被称为体液免疫应答
Some T-cells take signals from the dendritic cells or macrophages,
有些T细胞会接收树突状细胞或巨噬细胞的信号
and are thus called helper T-cells.
所以也被称为辅助T细胞
They perform two key tasks:
它有两个关键任务:
forming effector T-cells, which are basically cells that cycle through the body
形成效应T细胞 在体内循环
and call in the cavalry, namely other white blood cells.
并且呼叫“骑兵” 即其他白细胞
Helper T-cells also form memory T-cells,
辅助T细胞还会形成记忆T细胞
which keep a record of this antigen for future reference.
它们会记录下这个病原体供下次参考
Sometimes, some cells of our body know that they have lost the battle.
有时 身体的某些细胞知道自己打了败仗
They have become heavily infected with pathogens,
它们被病原体严重感染了
so there is no hope for them.
所以已经没救了
At this point, the immune system brings out the cytotoxic t cells.
此时 免疫系统会叫来细胞毒性T细胞
These cells rush over and perform a mercy killing for the infected and dying cell.
跑去给濒死的感染细胞安乐死
Furthermore, we have the B-cells.
此外 我们还有B细胞
They produce chemicals called antibodies,
它们会产生名为抗体的化学物质
which fit on the antigens of pathogens,
抗体与病原体的抗原相结合
much like how a lock and key fit together.
就像锁和钥匙组合在一起
These antibodies crowd around a pathogen and act like tags,
这些抗体会在病原体上聚集 并作为标签
They signal the macrophages to come and kill the marked pathogen.
指示巨噬细胞来杀死被标记的病原体
B-cells also produce memory B-cells when they encounter an antigen.
B细胞遇到抗原时也会产生记忆B细胞
The B- and T- memory cells jointly maintain a record of all encountered infections,
记忆B T细胞对所有遭遇过的感染都有记忆功能
and thus strengthen and solidify the body’s immune response to these infections in the future.
从而加强并稳固将来对于这些感染的免疫应答
Our innate response is quicker, though non-specific.
固有免疫应答不具有特异性 但它非常迅速
It gets into action within hours and is pretty strong.
几小时内就能起作用 效果也很好
However, when things get out of hand,
然而 当情况失控时
the innate system calls for help from the acquired immune system.
固有免疫系统会向获得性免疫系统寻求帮助
This system can take days to mount a response,
这个系统要花几天才能做出应答
but the next time we encounter that pathogen,
但是下次遇到这个病原体
it won’t make us get sick.
我们就不会生病了
In short, every day that we spend being healthy
总之 我们能健康地度过每一天
is all thanks to our immune system.
都要归功于免疫系统
So, it definitely deserves our respect.
所以它绝对值得我们尊重

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视频概述

解说固有免疫和适应性免疫

听录译者

收集自网络

翻译译者

Syllab

审核员

审核员LJ

视频来源

https://www.youtube.com/watch?v=PzunOgYHeyg

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