Meet the Players: Barriers, Innate Defenders, and Adaptive Specialists

The Tour of the Body series spotlight on the Immune System continues—we're getting to know the actual players that make your immune system tick—from your skin and stomach acid to your B-cells and natural killer cells. These defenders work in layers, communicating across your body to protect, repair, and recalibrate. Want to understand how your immune system knows when to fight, when to rest, and how to remember past threats? Let’s meet the team.