Description: The MEM-43 monoclonal antibody reacts with human CD59, also known as protectin, membrane inhibitor of reactive lysis (MIRL), and membrane-attack-complex-inhibitory factor (MACIF). CD59 is an approximately 19 kDa GPI-linked glycoprotein expressed by hematopoietic and non-hematopoietic cells. Through binding complement components C8 and C9, CD59 inhibits the assembly of the membrane attack complex and the cytolytic activity by complement. CD59 also interacts with CD2 and has a role in T cell activation.