CD19 antibody human specific - HS-439 103

CD19 (Cluster of Differentiation 19) is a B cell-restricted signal-transduction molecule that plays an important role in the regulation of development, activation, and differentiation of B-lymphocytes. CD19 is considered as a biomarker for B-cells because of its continued expression from very early B cell development stages, being evident already on pro-B cells and on all later B cell stages, until plasma cell terminal differentiation, when its expression is lost. In complex with CD21 (complement receptor-2), CD81 and CD225 (Leu-13), CD19 functions as a dominant signaling receptor on the surface of mature B cells (1). CD19 is instrumental in B cell homeostasis and lowers the threshold of B cell receptor crosslinking necessary to effect B-cell activation and sustain proliferation upon antigen encounter (2). Dysregulated CD19 expression has been implicated in several autoimmune diseases and CD19 is expressed in most acute lymphoblastic leukemias (ALL), chronic lymphocytic leukemias (CLL) and other B cell lymphomas (3). Therefore, CD19 has gained attention as a potential target in the therapy of B-cell malignancies (4).