Outline the role of phagocytic white blood cells in defence against pathogens

Phagocytes are part of the innate immune system. They are primarily responsible for clearing extracellular infections e.g. bacteria or fungus, by recognising and ingesting the pathogen. Typically, pathogens will be covered in specific antibodies which mark them for digestion (opsonisation), but phagocytes may also recognise structures of of bacterial cell wall. Upon phagocytosis, the pathogen is engulfed into a vesicle and destroyed.