CD40 belongs to the TNF-receptor superfamily and is essential in mediating a broad variety of immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. The interaction of CD40-CD40L is necessary for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis. CD40 is constitutively expressed by antigen presenting cells, including dendritic cells, B cells and macrophages. Consistent with its widespread expression on normal cells, CD40 is also expressed on a wide range of tumor cells, including non-Hodgkin's and Hodgkin's lymphomas, myeloma and some carcinomas including nasopharynx, bladder, cervix, kidney and ovary.
Functional Application: Activates B and NK cells in vivo and in vitro.