CD20 (MS4A1) is a glycosylated phosphoprotein expressed on the cell surface of B cells. Although the functional significance of CD20 is not clear, and CD20 has no known ligands, CD20 has been shown to regulate intracellular calcium levels. CD20 is a highly attractive target antigen for immunotherapy because it is expressed in more than 90% of patients with B-cell lymphoma. First approved in 1997, Rituximab (Rituxan) is a chimeric monoclonal antibody targeting CD20 and has been classified by the World Health Organization as an "Essential Medicine". Since then, additional monoclonal antibodies against CD20 have been approved or are being tested in clinical trials for the treatment of multiple sclerosis (MS), chronic lymphocytic leukemia (CLL), follicular lymphoma, diffuse large B cell lymphoma (DLBCL), rheumatoid arthritis, non-Hodgkin"s lymphoma, systemic lupus erythematosus, and myalgic encephalomyelitis (chronic fatigue syndrome).The IgM pentameric structure is supposed to produce a stronger binding to cells with low expression of CD20, as well as greater ability to cross-link cell surface receptors for increased cellular signaling. In the meantime, because of the ratio of anti CD20- and anti CD3-antibodies, the cytokine release is supposed to be reduced.
Clonality
Monoclonal (Bispecific)
Description
His-tagged Anti-CD20-Anti-CD3 IgM format bispecific antibody is a purified recombinant human bispecific antibody with T cell Engager. This bispecific antibody has been tested for specific activity in the functional reporter assay using NFAT-luc reporter Jurkat cell line (BPS Bioscience #60621) in the presence of CD20-CHO cells (BPS Bioscience #79624-H). The IgM Fc region is pentameric, so there are 5 copies of the anti-CD20 antibodies and J chain has anti-CD3 antibody.
assay conditions: Experimental design and assay protocol for measuring anti CD20-anti CD3 functional activity using NFAT-luc reporter Jurkat cell line: Jurkat effector cells with endogenous TCR/CD3 and transfected reporter NFAT-luc (BPS Bioscience #60621) are incubated with increasing concentrations of anti CD20 x anti CD3 bispecific antibody in the presence of CD20-CHO cells (BPS Bioscience #79624-H) or CHO cells (ATCC #CCL-61). 1. Seed CHO and CD20-CHO cells at 30,000 cells/well and allow a few hours for the cells to attach in a 96-well clear bottom white plate. 2. Seed Jurkat cells at 30,000 cells/well. 3. Add the bispecific antibody at a recommended dilution range of 100 fM-100 nM. The bispecific antibody simultaneously binds to TCR/CD3 on the NFAT-luc Jurkat reporter cells and tumor antigen CD20 on CD20-CHO cells. 4. After 16 hours the luciferase activity is measured using ONE-Step luciferase assay (BPS Bioscience #60690) per recommended protocol. The bispecific antibody interaction stimulates NFAT-luciferase activity.
Formulation
8 mM phosphate, 110 mM NaCl, 2.2 mM KCl, pH 7.4, and 20% glycerol