FITC-Labeled CD19 Protein

The N-terminal fragment of pro-brain natriuretic peptide (N-terminal-prohormone Brain Natriuretic Peptide, NT-proBNP), whose molecular weight is 8.5kDa, belongs to the natriuretic peptide family protein, also known as type B brain natriuretic peptide, which has the functions of natriuretic, diuretic, vasodilation and so on. NT-proBNP is mainly synthesized and secreted by ventricular myocytes. Cardiac dysfunction such as high ventricular load and increased wall tension are the main conditions for stimulating NT-proBNP secretion, and the intensity of these stimulating factors is proportional to the content of NT-proBNP. Therefore, NT-proBNP can reflect the changes of ventricular function with strong specificity and high sensitivity, is a very important clinical marker of heart failure, and plays an irreplaceable role in early heart failure screening, prognosis evaluation and so on.CD19 is a type-I transmembrane glycoprotein of 95 kDa that belongs to the immunoglobulin superfamily and is widely expressed on B cells throughout most stages of B-cell differentiation, though its expression is down-regulated during their terminal differentiation to plasma cells. CD19 maps to chromosome 16p11.2, where it encodes a 540 amino acid protein with two extracellular C-type IgSF domains as well as a large, approximately 240 residue, cytoplasmic tail that exhibits extensive conservation between mice and humans. CD19 is a signal amplifying coreceptor whose expression is restricted to B cells and follicular dendritic cells. CD19 exists in a multimolecular complex with CD21 (complement receptor type 2, CR2), the tetraspanin CD81 and CD225 on the B cell surface. Via its interaction with CD21, CD19 serves as a signal transducing device for complement-conjugated antigen in B cells. Coligation of the BCR and the CD19/CD21 complex lowers the threshold for B cell activation by approximately two orders of magnitude. CD19 is a potential target for monoclonal antibody therapy, and preliminary data have demonstrated its effectiveness in B-cell depletion, making this an attractive therapy for autoimmune disorders and treatment of malignant B-cell lymphomas. CD19 serves as an attractive target for immunotherapy for many reasons: (1) It is expressed on most B-cell malignancies; (2) it is expressed in the B-cell lineage at an early stage, even before the expression of CD20; (3) it internalizes efficiently in lymphoma tumor models252; and (4) it is possibly involved in the development of B-cell cancers.