A protein found on the surface of certain cells of the immune system that binds specifically to complement components coating the surface of a bacterium or other pathogen (see opsonization). There are several types of complement receptor associated with various cell types and binding specifically to different complement proteins. One of the most important is the CR1 receptor found on macrophages, monocytes, polymorphonuclear leucocytes, and erythrocytes. This plays a key role in stimulating the uptake and destruction of complement-coated target cells by macrophages. The CR3 receptor, found on B cells, helps in reinforcing the antibody response when the B cell encounters its specific antigenic target if the target is also coated with the corresponding complement protein.
Subjects: Medicine and Health — Biological Sciences.