The immune system is so cool and so important but it largely goes about its business without us knowing it. In this episode you'll get a front row seat as our immune cells (aka friendly monsters) fight off bacteria and viruses (aka bad robots). We'll also find out how vaccines provide important training for our immune cells. Plus, co-host Colin quizzes Molly on immune system facts and there's a brand new mystery sound!

This episode was brought to you by

Indeed (indeed.com/BRAINSON)

Interlochen Center for the Arts (interlochen.org/brainson Code: SAVE10)

Staples Connect (staplesconnect.com/printbig)

Little Passports (littlepassports.com/BRAINS)