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Season 5 Episode 17 | 6m 16s
| Video has closed captioning.
Do you remember having a cold in 5th grade? Or the flu a couple years ago? Your immune system does. Our bodies hold many levels of immune defense. Millions of B cells and T cells and antibodies are constantly on patrol for germs and antigen invaders. As scientists learn more about how this system works and how to engineer it, could we ever actually be immune to everything?
