The<unk><unk><unk>  (MAC) is typically formed on the surface of intruding pathogenic bacterial cells as a result of the activation of the<unk> ent system, and it is one of the ultimate weapons of the immune system.
Complement membrane attack complex
Complement system
Pattern recognition receptor
Soluble CD40 ligand 
Cytotoxic T cell
Adaptive immune system
Memory T cell
Acute phase protein