Rituximab (RITUXAN) Elisa
Rituximab (Rituxan) is a mouse/human chimeric monoclonal antibody used to treat B-cell malignancy, autoimmune conditions, and graft rejection by eliminating B cells from the body. This immunogenicity assay employs the bridging ELISA technique. Four levels of quality control samples provide a qualitative reference signal that can be used to determine the level of anti-Rituximab antibodies in the unknown samples. Colour development is stopped and the intensity of the colour is measured.
Principle of the Test
This immunogenicity assay employs the bridging ELISA technique. The capture antibody is pre-coated in a 96-well microplate. Quality control and test samples are pipetted into the appropriate wells. Anti-Rituximab present in the biological matrices binds to the immobilized capture antibody. After washing away unbound material, a secondary antibody is added to the wells, and after a final wash, a detection reagent is added. The plate is washed to remove any unbound antibody-enzyme reagent and substrate solution is added to the wells for colour development. Colour development is proportional to the amount of anti-Rituximab present in the test samples.
Product Information Rituximab (Rituxan)
- Application: free drug
- The volume required (uL): 10
- Total Time (min): 135
- Example type: Serum, Plasma
- Number of trials: 96
- The detection limit (ng/mL): 3 (ng/mL)
- Peak Recovery (%): 85-115%
- Useful life (year): 1
- anti-CD20 mAb
Rituximab mode of action (Rituxan)
Rituximab is a genetically engineered chimeric murine/human monoclonal antibody directed against the CD20 antigen found on the surface of normal and malignant B lymphocytes. The antibody is a glycated IgG1 kappa immunoglobulin containing murine heavy and light chain variable region sequences (Fab domain) and human constant region sequences (Fc domain). Rituximab is composed of 1,328 amino acids and has an approximate molecular weight of 144 kD. Rituximab has a high binding affinity for the CD20 antigen of 5.2 to 11.0 nM. Rituximab specifically binds to the CD20 antigen, a transmembrane molecule located on pre-B and mature B lymphocytes.
Uses of Rituximab (Rituxan)
Rituximab is a CD20-directed cytolytic antibody indicated for the treatment of patients with: non-Hodgkin lymphoma (NHL), chronic lymphocytic leukaemia, rheumatoid arthritis (RA) in combination with methotrexate in adult patients with moderately to severely active RA who have an inadequate response to one or more TNF-blocking therapies, Wegener’s granulomatosis (WG) and microscopic polyangiitis (MPA) in adult patients in combination with glucocorticoids.
Treatment with rituximab (Rituxan)
The CD20 antigen is expressed on > 95% of all B-cell non-Hodgkin lymphomas (NHL). CD20 (human B cell-restricted differentiation antigen, Bp35) is a hydrophobic transmembrane protein with a molecular weight of approximately 35 kD. This unglycosylated phosphoprotein is found in both normal and malignant B cells, but not in hematopoietic stem cells, pro-B cells, normal plasma cells, or other normal tissues. CD20 regulates (one) early step(s) in the activation process for cell cycle initiation and differentiation, and possibly functions as a calcium ion channel
CD20 is not internalized upon antibody binding and is not removed from the cell surface. This antigen does not circulate in plasma. Therefore, free antigen does not compete for rituximab binding. The Fab domain of rituximab binds to the CD20 antigen on B lymphocytes, and the Fc domain recruits immune effector functions to mediate B cell lysis. Potential mechanisms of cell lysis include complement-dependent cytotoxicity (CDC) and cytotoxicity. antibody-dependent cell (ADCC).
The antibody also induces apoptosis in the DHL-4 human B-cell lymphoma line, and in vitro studies have shown that rituximab sensitizes drug-resistant human B-cell lymphoma lines to the cytotoxic effects of some chemotherapeutic agents. In human tissue, expression of the CD20 antigen is highly restricted; Rituximab binding to CD20 was found only on lymphoid cells of the thymus, the white pulp of the spleen, and most B lymphocytes in peripheral blood and lymph nodes. Little or no non-specific binding was observed.