Glimmers in the Darkness IMMUNITY EXPLAINED

The study of immune biology started with the microscope, and a mess of cells strained out of the blood by a biologist’s porcelain filter. The ones that were red were recognised as the blood cells that shuttle oxygen through the body. The cells that weren’t red were called ‘white,’ in the sense that non-red wine is called white. These white blood cells are also called leukocytes. (The Greek root for white is leuk and for cell is cyt.) The term still refers to any cell that’s part of the immune system.

The first aspect of immune response to be grasped by nineteenth century biologists was the oldest and most primitive, a 500-million-year-old personal defense system we call the innate immune system.

Immune cells were originally assumed to be all be the same. It would take more than a simple microscope however, to reveal that our bloodstream in fact contains an exotic ecosystem of specialised players bound in an elegant and potent web of personal defense. The innate immune system is charismatic and deceptively straightforward.