They form part of the mononuclear phagocyte system. The target cells are those of mononuclear phagocyte system. This process characterizes neutrophils as a type of phagocyte. ITAM domains transduce the signal from the surface of the phagocyte to the nucleus. The exact properties of phagolysosomes vary depending on the type of phagocyte. The Molecular Biology of Phagocytes and of Nonneoplastic Phagocyte Disorders. This binding will lead to the engulfing of the bacteria by the phagocyte. The spleen is the largest unit of the mononuclear phagocyte system. Exoerythrocytic schizogony occurs in the mononuclear phagocyte system. As a result, bacteria may thrive within the phagocyte. To get safely inside the phagocyte they express proteins called invasins. Complement coated targets are internalised by 'sinking' into the phagocyte membrane, without any protrusions. Once inside this phagocyte, the bacterium is trapped in a compartment called a phagosome. This type of phagocyte does not have granules but contains many lysosomes. Thus, NADPH oxidase is critical for phagocyte killing of bacteria through reactive oxygen species.