What process do white blood cells use to engulf and destroy pathogens?

White blood cells utilize phagocytosis as their primary mechanism for engulfing and destroying pathogens. Phagocytosis is a process where cells extend their membrane around a pathogen, forming a pocket that eventually engulfs the pathogen within a vesicle called a phagosome. Once inside the cell, the phagosome fuses with lysosomes, which contain enzymes that break down and digest the pathogen. This process is crucial for the immune response, as it enables white blood cells to effectively eliminate harmful microorganisms and prevent infections.

In contrast, exocytosis involves the expulsion of materials from the cell, diffusion refers to the passive movement of particles from an area of high concentration to an area of low concentration, and filtration typically refers to the mechanical process of separating substances, which is not how white blood cells deal with pathogens. Thus, phagocytosis is specifically adapted for the immune function that white blood cells perform.