Some bacteria produce adhesion molecules called invasins that activate the host cell's cytoskeletal machinery enabling bacterial entry into the cell by phagocytosis. These bacteria produce what is called type III secretion systems. When the bacteria contact nonimmune eukaryotic cells), they deliver proteins into the cells enabling them to engulf the bacterium and place it in a vacuole. The bacterium is then released from the vacuole, multiplies in the cytoplasm of the cell.