The monoclonal antibody WU 4-15 recognizes C7, which is one of the components of the terminal complement complex (TCC), also known as the membrane attack complex (MAC). The proteolytic cleavage of C5 by C5 convertase produces C5b, which initiates the assembly of C5b-9 MAC. The complex is assembled from five precursor molecules in the serum, and finally with the polymerization of C9, the complex is inserted into the cell membrane to cause cell lysis. C7 occupies an important position in the TCC cascade. C7 undergoes a hydrophilic-amphiphilic transition after activation. It allows the developing MAC to directly bind to the target cell membrane. It has been demonstrated that C7 exhibits genetic polymorphism. Polymorphonuclear leukocytes represent the main source of C7. The fact that inflammatory cells have the potential to secrete C7 indicates that locally produced complement plays an important role in the inflammatory process. The monoclonal antibody WU 4-15 can recognize a specific allotype of C7: C7M. 62% of whites are homozygous for C7 M and 31% are heterozygous. Wu 4-15 antibody can quantify the contribution of locally synthesized C7 to the inflammatory process and identify allotypes.