How does phagocytosis occur in macrophages?

A macrophage attaches to a pathogen by the receptors on the pathogen and macrophage binding. The pathogen is then engulfed and a phagosome forms, where a vesicle surrounds the pathogen. A lysosome moves towards this and fuses with the phagosome so forming a phagolysosome, where enzymes such as lysins digest the pathogen into amino acids. Part of the pathogen is moved to a receptor on the macrophage called the MHCII, and is 'presented' on this, hence the macrophage becomes an antigen presenting cell.