Our Immune Systems Are Full of Ancient Weapons

Welcome to the show, Vivian.

Thanks so much for having me.

So Vivian, what's the big idea?

So the big surprise here was that some of these bacterial defenses against phages exist in our cells, too, and they really haven't changed that much, even though we've been separated from bacteria for billions of years, evolutionarily speaking.

And the reason that this is surprising is that arms races tend to drive the evolution of novelty, of new adaptations, 'cause a species is always trying to stay ahead of an evolutionary challenge.

And so immunologists had believed for a long time that these arms races would drive very idiosyncratic solutions in different lineages of life.

So every lineage would find its own solution to defend against infection.

But what we're finding is that that's actually not true, and the same solutions seems to be used again and again all over the tree of life.