Phagocytosis
This process is carried out by a specific white blood cell, called a phagocyte. These are found in the blood and tissues of the body, they are the first cells to respond to a foreign antigen.
The phagocyte recognises the pathogen and its antigens as foreign. It engulfs the pathogen by moving the phagocyte's cytoplasm around it - containing it in a phagocytic vacuole. A lysosome, which contains hydrolytic enzymes called lysozymes fuses with the phagocytic vacuole. The lysozymes break down the pathogen, then the phagocyte presents the antigens on its cell-surface membrane to activate the other immune cells.