Activated MacrophageMacrophages are big and smart white blood cells that chase, capture, engulf, and digest intruders. They trap and phagocytize (literally, “eat”) their enemies. They can multiply rapidly when necessary. However, they’re naturally indolent and need to be activated by Vitamin D.

Here’s how it works. When a macrophage isn’t swimming in the blood stream, a it can slowly “walk” through tissues using self-generated stumpy little (one micron) “legs” (about ten of them sprout at a time). The macrophage ambles over to and snuggles up alongside a pathogen, quickly identifies it as foe, sprays it with membrane-frying free radical-laden beams, grabs, engulfs, smothers, kills, and digests them. If the pathogen is further away, or trying to escape, the macrophage chases after it, extrudes a cluster of long thin sticky spaghetti-like tentacles that wrap around and ensnare the pathogen, clutching it in an unbreakable strangle hold.

It is totally amazing that this complex and truly violent scenario is unfolding in you and me billions of times per minute.