Description: Mediates B-cell proliferation in the absence of co-stimulus as well as IgE production in the presence of IL-4. Involved in immunoglobulin class switching. (www.uniprot.org) Produced in E.coli as a non-glycosylated, polypeptide chain containing 149 amino acids. The CD40 ligand stimulates B-cell proliferation and secretion of all immunoglobulin isotypes in the presence of cytokines.