Episode 4

"The Weakest Link"
Synopsis

 

The immune system protects us from external threats, like deadly bacteria and viruses.

It is a complex system of organs and tubes through which specialized classes of cells travel to tend to their jobs, whether it is to produce and release antibodies, to kill cells that have become infected with viruses, or to close up open wounds.

However, the immune system is far from perfect, and cannot offer  100% protection.

Many harmful microbes can slip through the cracks of the immune system and infect us nonetheless.

Some, like HIV, can even hijack the system itself. Sometimes, in the absence of external threats, our immune system can turn on us and relentlessly attack our own bodies.

How did the immune system evolve?

What are the main ‘mistakes’ in the way the immune system evolved?

And how could we invent a better defense system?

The episode features scientists that are re-designing the immune system and even using it as a vehicle to change normal
human physiology.

What is “immunotherapy” and how does it work?

In recent years, an anti-vaccination movement has developed in the Western World;. The episode investigates how vaccines work and what happens in the absence of vaccinations.