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 BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).