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How do white blood cells protect the body from infectious organisms?
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Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).
White blood cells, or leukocytes, protect the body from infectious organisms through several specialized defense mechanisms. Their primary methods include:12
- Phagocytosis: Neutrophils and macrophages act as "cell-eating" scavengers. They migrate to sites of infection, engulf pathogens like bacteria, and digest them using enzymes contained within lysosomes.314
- Antibody Production: B cells secrete antibodies, which are proteins that bind to foreign microorganisms. This process can neutralize invaders directly or mark them for destruction by other immune components, such as the complement system.152
- Cell-Mediated Immunity: T cells identify and destroy cells that have been compromised by viruses or cancer. Unlike B cells, they provide protection through direct interaction with infected cells rather than by secreting antibodies.15
- Inflammatory Response: Certain white cells release chemicals that induce inflammation, helping to recruit more immune cells to the site of infection and modulate the body's overall response.13
These cells are highly differentiated, allowing them to work in concert to recognize, target, and eliminate diverse threats to the body.12