Interaction Between Cd19 and Antibody B43

Abstract

CD19 is a transmembrane protein found on the surface of, and unique to, all B cell lineages. This property allows it to function as the primary antigen for B cell specific antibodies, such as antibody B43. Functioning as the primary antibody for targeting CD19, B43 is currently utilized in genetically engineered T cells for the treatment of acute lymphoblastic leukemia. To learn more and improve upon this binding, we utilized the crystal structure of B43 complexed with CD19 to understand the interactions between the two proteins. This structure showed that it would be reasonable to state that the binding between the epitope and the antigen recognition sites follows a lock and key fashion. Plus, the complexed structure revealed a unique molecular orientation for the extracellular domain of CD19 showing an elongated Beta sandwich. A better understanding of the binding would provide the way to design a more efficient antibody.