CD19 is one of the earliest discovered markers on the surface of B lymphocytes, aliased as B4 or Leu-12. It is a glycosylated type I transmembrane protein with a relative molecular mass of 95 kDa on the surface of B cells. It belongs to immunoglobulin (Ig) super family members.
The expression of CD19 molecule begins in bone marrow B progenitor cells and continues throughout the maturation stage of B cells until it disappears when differentiated into plasma cells. It mainly regulates the activation and development of B cells and is widely distributed on the surface of B lymphocytes. It is a function Sex receptor molecules. In addition, CD19 is also expressed on malignant B-cell tumor cells and follicular dendritic cells. It is also expressed on acute myeloid leukemia cells.
CD19 is an important signal transduction molecule that regulates the growth, activation and activation of B lymphocytes, and plays an important role in regulating the signal threshold of B lymphocyte antigen receptors or other surface receptors. It is to differentiate, activate, and activate B lymphocytes. Important membrane antigens related to proliferation and antibody production are the best markers for diagnosing B lymphocyte tumors and identifying B lymphocytes. As a landmark target of B-cell tumors, CD19 first appeared in advanced progenitor B cells and early pre-B cells. It is expressed during the entire process of B cell maturation and final differentiation into plasma cells, but not expressed in hematopoietic stem cells and other tissue cells. After splicing the gene sequence of the variable region of the antibody that recognizes CD19 with the sequence of the intracellular region of the lymphocyte immune receptor, they are transfected into the patient’s T cells, and the resulting CD19 CAR-T cells can specifically attack the B cells with the CD19 antigen. Thereby promoting the body to eliminate tumor cells with CD19 antigen. The CD19 chimeric antigen receptor is a gene recombination technology that combines the single-chain variable region of an antibody that specifically recognizes CD19 with an extracellular hinge region, transmembrane domain, and one or more intracellular T cells to stimulate or co- A fusion protein expressed on the surface of T cells formed by the fusion of stimulating molecules.
The current successful clinical application of CD19 CAR-T cells is based on numerous preclinical and clinical studies. Although differences in CAR structure design, production strategies, and clinical delivery make it difficult to compare the results of different clinical trials, some key models to guide the future optimization of CAR-T cell immunotherapy are already being explored.