The body’s killer T cells

Our bodies’ killer T cells are “not known for their mercy”, says Katherine Wu in The Atlantic – and they could “help hold the line against hospitalisations and deaths” in the fight against omicron. Like antibodies, T cells are a crucial part of our immune system. But whereas antibodies are “powerful but simple sentinels” that wander around the body trying to neutralise pathogens, T cells are “immunological assassins”, targeting cells that have already been infected. And when they find one, “their first instinct is to butcher”.

The killer T punches holes in the rogue cell and pumps in toxins so the cell is destroyed along with the virus. That’s the whole idea: “virus-infected cells must die” so the rest may live. Helpfully, infected cells are relatively easy to spot because they sometimes chop up part of the virus within them and display the mangled shreds on their outside. The dismembered bits are “gross but effective”: nothing makes killer Ts go wild more than “a hunk of mutilated virus splattered onto the surface of an infected cell”.