Final answer:
The major role of PMNs, specifically neutrophils, is to ingest and eliminate microorganisms. They are part of the innate immune system and act by phagocytosing pathogens and releasing cytokines that aid in pathogen destruction.
Step-by-step explanation:
The major role of polymorphonuclear leukocytes (PMNs), which includes neutrophils, is to ingest and eliminate microorganisms. They are phagocytic cells that act as the first responders to infection. PMNs engulf pathogens and, upon activation, produce large quantities of cytokines that facilitate the destruction and removal of pathogens from the body. T
he process of phagocytosis and the subsequent release of cytokines are crucial in the body's innate immune response and in signaling to other components of the immune system to act against infections.