T00704 Recombinant human CD19 (hFc Tag)

产品信息(Information)：

背景介绍(Background)：

This gene encodes a member of the immunoglobulin gene superfamily. Expression of this cell surface protein is restricted to B cell lymphocytes. This protein is a reliable marker for pre-B cells but its expression diminishes during terminal B cell differentiation in antibody secreting plasma cells. The protein has two N-terminal extracellular Ig-like domains separated by a non-Ig-like domain, a hydrophobic transmembrane domain, and a large C-terminal cytoplasmic domain. This protein forms a complex with several membrane proteins including complement receptor type 2 (CD21) and tetraspanin (CD81) and this complex reduces the threshold for antigen-initiated B cell activation. Activation of this B-cell antigen receptor complex activates the phosphatidylinositol 3-kinase signalling pathway and the subsequent release of intracellular stores of calcium ions. This protein is a target of chimeric antigen receptor (CAR) T-cells used in the treatment of lymphoblastic leukemia. Mutations in this gene are associated with the disease common variable immunodeficiency 3 (CVID3) which results in a failure of B-cell differentiation and impaired secretion of immunoglobulins. CVID3 is characterized by hypogammaglobulinemia, an inability to mount an antibody response to antigen, and recurrent bacterial infections. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2020].

CD19 (95 kDa) is a B cell specific member of the immunoglobulin super-family expressed by early pre-B cells from the time of heavy chain rearrangement until plasma cell differentiation. CD19 is classified as a type I transmembrane protein, with a single transmembrane domain, a cytoplasmic C-terminus, and extracellular N-terminus. CD19 has a 240-amino acid cytoplasmic domain that contains nine conserved tyrosine residues, which play a critical role in the transduction of CD19-mediated signals. As a hallmark antigen of the B-cell lineage, CD19 is a well-known co-receptor for BCR signaling. CD19 is critically involved in establishing intrinsic B cell signaling thresholds through modulating BCR signaling. CD19 is a double-edged sword, which functions as both positive and negative regulator in BCR signaling. On the one hand, co-ligation of CD19 with the BCR synergistically enhances mitogen-activated protein (MAP) kinase activity, calcium release and proliferation. On the other hand, ligation of CD19 away from BCR complex suppresses BCR signal transduction. Since CD19 is expressed throughout B-cell development and plays a critical role in maintaining the balance between humoral, antigen-induced immune response and tolerance induction, CD19 targeted immunotherapy is emerging as a promising approach for autoimmunity diseases and B cell lymphomas.

图 CD19分子结构

制剂(Formulation)：

Lyophilized from 0.22 μm filtered solution in PBS，5%mannital，0.01% Tween80 pH7.4. 

质量控制(Quality Control)：

Purity: ≥ 95% as determined by reducing SDS-PAGE.    

Endotoxin: ＜ 0.1 EU/ug  as determined by LAL test.

保存(Storage)：

Use a manual defrost freezer and avoid repeated freeze - thaw cycles.
12 months from date of receipt, -20 to -70℃ as supplied.
1 month, 2 to 8℃ under sterile conditions after reconstitution.
6 months, -20 to -70℃ under sterile conditions after reconstitution.   

FOR RESEARCH USE ONLY

参考文献：

[1] Li X, et al. 2017. Immunol Lett. 183: 86-95.

[2] Xu Y, et al. 2014. Autoimmunity. 47(7):430-7.

[3] Wang K, et al. 2012. Exp Hematol Oncol, 36.