The T21 monoclonal antibody specifically binds to CD125 which is also known as the alpha subunit of the IL-5 Receptor (IL5RA/IL-5Rα). CD125 is a type I transmembrane protein that belongs to the hemopoietin receptor and Ig gene superfamilies. It is expressed on B cells and eosinophils. CD125 associates with the Common β chain (βc/Bc) subunit, also known as CD131, to form the functional IL-5 Receptor complex. Mouse IL-5 belongs to the hematopoietic growth factor family of cytokines and promotes the growth and differentiation of B cells and eosinophils. Upon binding, the T21 antibody blocks IL-5 binding to its receptor and can inhibit IL-5 induced B-cell proliferation and antibody production.
The antibody was conjugated to BD Horizon Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.