The activation of macrophages and methods for treating cancer, bacterial pathogens and viral pathogens are disclosed. In particular, Gc protein is converted to Gc-macrophage activating factor (GcMAF), or . The GcMAF activates macrophages which can then target cancer cells, bacterial pathogens and/or viral pathogens. Alternatively, macrophages are activated by contacting them, or, with GcMAF. Optionally, nagalase is inactivated in a patient receiving the present macrophage activating treatment by contacting the patient's blood with a Nagalase-binding ligand immobilized on an inert medium.
