CD19 (Cluster of differentiation 19), also known as B-lymphocyte antigen CD19, is a 95 kDa transmembrane glycoprotein on the surface of the immunoglobulin superfamily (IgSF) and classified as a type I one-pass transmembrane protein. It maps to the short arm of chromosome 16p11.2 encoded by the 7.41 kilobite CD19 gene that produces a 556-amino acid protein with two extracellular C-type IgSF domains together with a 242-residue cytoplasmic tail that exhibits highly conservation between mouse and human. The CD19 molecules are expressed from the earliest stage of B cells development until plasma cells terminal differentiation. It can associate with the B cell antigen receptor (BCR), CD81 (TAPA-1), CD38, CD21, CD22 and CD225 to establish intrinsic B cell signaling and reduce the thresholds. CD59 molecule (Complement regulatory protein), also referred to CD59 antigen, MIRL (Membrane inhibitor of reactive lysis), MAC-IP (MAC-inhibitory protein) or protectin, is a 20kDa GPI-anchored cell surface glycoprotein, encoded in humans by CD59 gene that localized at the chromosome 11p13. It has sites for both N- and O-glycosylation and is a member of the LY6/uPAR/alpha-neurotoxin protein family. CD59 is a single chain of 128 amino acids, structurally homologous to snake venom neurotoxins. This protein is expressed virtually in all or tissues and in almost all cell types. CD59 plays a role in regulating complement-mediated cell lysis and participates in lymphocyte signal transduction. It is a potent inhibitor of the complement membrane attack complex and its expression essential for the survival of erythrocytes upon homologous complement activation.