Description
Interleukin 5 (IL-5) is a species-crossreactive cytokine produced by mast cells, T cells and eosinophils. It induces the proliferation, differentiation and activation of eosinophils. It is also a growth and differentiation factor for mouse B cells. IL-5 is an antiparallel disulphide-linked homodimer of molecular mass of approximately 45 kDa. Mature IL-5 monomers contain 113 amino acid residues and 3 glycosylation sites. IL-5 binds to a specific heterodimeric cell surface receptor formed by two subunits, the binding IL-5Ra subunit and the non-binding b subunit, also shared by the receptors for IL-3 and GM-CSF, thus termed b-common (bc). Due to heterogeneous glycosylation, recombinant IL-5 resolves into multiple bands ranging from 32-34 kDa in SDS-PAGE