Recombinant Human CD19-Fc Chimera (carrier-free) 100 µg

CD19 is a 95 kD transmembrane glycoprotein that functions as a co-receptor for the B-cell antigen receptor (BCR) complex on B lymphocytes. CD19 is expressed throughout B cell development, and it is commonly used as a B-cell lineage marker. CD19 plays an important role in B-cell activation and humoral immune responses. It is required for the responsiveness of mature B cells to antigen stimulation, germinal center development, and antibody affinity maturation. CD19's association with the BCR, CD81, CD38, CD21, CD22, and IFITM1/CD225/Leu13 enables CD19 to amplify B-cell signaling and decreases the threshold for activation of downstream signaling pathways and for triggering B-cell responses to antigens. CD19 activates signaling pathways that lead to the activation of phosphatidylinositol 3-kinase and the mobilization of intracellular Ca²⁺ stores. CD19 polymorphisms are associated with the development of autoimmunity by promoting autoantibody production. Homozygous mutations in CD19 cause a type of hypogammaglobulinemia in which the response of mature B cells to antigenic stimulation is defective.;