Macrophages: Key Players in Immunity and Tissue Repair

Macrophages are large, motile white blood cells specialized for phagocytosis—the engulfing and digestion of foreign particles, bacteria, and cellular debris.

Roles

• Innate Immunity: First line of defense against pathogens; present antigens to T cells to initiate adaptive immunity.
• Tissue Repair: Clear dead cells and release growth factors that promote healing and regeneration.
• Homeostasis: Maintain tissue integrity by removing aged or damaged cells.

Macrophages originate from monocytes that migrate from the bloodstream into tissues, where they differentiate into resident macrophages (e.g., Kupffer cells in the liver, microglia in the brain, alveolar macrophages in the lungs).