INTRODUCTION

Tocilizumab (Actemra®) is an immunosuppressive humanized monoclonal antibody drug, mainly for the treatment of rheumatoid arthritis (RA) and systemic juvenile idiopathic arthritis, a severe form of arthritis in children. Tocilizumab binds the interleukin-6 receptor (IL-6R) thus blocking the signaling caused by interleukin 6 (IL-6). IL-6 is a cytokine that plays an important role in immune response and is implicated in the pathogenesis of many diseases.

The Tocilizumab ELISA kit is designed to measure free Tocilizumab with high specificity and sensitivity.

PRINCIPLE OF THE ASSAY

This assay employs the sandwich enzyme immunoassay technique. Anti- Tocilizumab is coated onto a 96 well microplate. Calibrator and test samples are pipetted into the appropriate wells. Tocilizumab present in biological matrices is bound by the immobilized anti- Tocilizumab antibody. After washing away any unbound substances, enzyme linked anti- Tocilizumab antibody is added to the wells. This antibody is developed and purified specifically against Actemra® (domain residing in Fc portion of the Actemra® molecule). The plate is washed to remove any unbound antibody-enzyme reagent and a substrate solution is added to the wells for color development. The color development is proportional to the amount of Tocilizumab present in test samples. The color development is stopped and the intensity of the color is measured.