CD154, clone 89-76, is derived from hybridization of mouse NS-1 cells with spleen cells from BALB/c mice immunized with sgp39-CD8 and activated human peripheral blood lymphocytes (PBLs).
CD154 (CD40 ligand or CD40L) recognizes a 39-kilodalton (kDa) antigen that is a member of the tumor necrosis factor (TNF) receptor family. CD154 is transiently expressed on activated CD4 T lymphocytes. The expression of CD154 by activated T-helper cells triggers B-cell cycling through binding to CD40. This co-receptor interaction is required for B-lymphocyte maturation, response to T-dependent ligands, and isotype switching. T-lymphocyte proliferation and generation of cytotoxic T lymphocytes (CTLs) is associated with the presence of CD154. Defects in the CD154 gene are associated with the X-linked hyper IgM syndrome.