Macrophages 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 VDBP.
Opsonin “super glue” helps them stick to their prey. Their electron-driven free radical death ray (AKA “oxidative burst”) blasts holes in microbes and cancer cells. Once a microbe or cancer cell has been phagocytized by a macro, it is encapsulated inside a “phagolysosome” (the intracellular “death chamber”), where it is then killed (if it isn’t dead already), and then dissected down into its component parts, which are then recycled.
Here’s how it works. When it isn’t swimming in the blood stream, a macrophage 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 “foreign invader” (e.g., cancer cell or virion), quickly identifies it as foe, sprays it with membrane-frying free radical-laden bursts, grabs, engulfs, smothers, kills, and digests it. If the enemy 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 fugitive cell, clutching it in an unbreakable strangle hold.
In a process known as phagocytosis, the macrophage draws in its victim, engulfs and smothers it, then encases it in a small bubble-like cyst (called a phagolysosome) inside its cytoplasm. The phagolysosome then secretes a cocktail of corrosive free radicals and enzymes that rapidly digest its victim down into its component parts (amino acids, nucleic acids, fatty acids, etc.). The macrophage then spits out these pieces into the intercellular “soup.”
Because the remnants of viruses and cancer cells are fundamental cellular building blocks, the body quickly recycles them using the “spare parts” to build brand new healthy cells.