CD40 Ligand Protein (CD40LG) Human Active Protein

CD40LG: 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. Defects in CD40LG are the cause of X-linked immunodeficiency with hyper-IgM type 1 (HIGM1); also known as X-linked hyper IgM syndrome (XHIM). HIGM1 is an immunoglobulin isotype switch defect characterized by elevated concentrations of serum IgM and decreased amounts of all other isotypes. Affected males present at an early age (usually within the first year of life) recurrent bacterial and opportunistic infections, including Pneumocystis carinii pneumonia and intractable diarrhea due to cryptosporidium infection. Despite substitution treatment with intravenous immunoglobulin, the overall prognosis is rather poor, with a death rate of about 10% before adolescence. Belongs to the tumor necrosis factor family.

Protein type: Cell adhesion; Membrane protein, integral

Chromosomal Location of Human Ortholog: Xq26.3

Cellular Component: cell surface; integral to plasma membrane; plasma membrane

Molecular Function: CD40 receptor binding; protein binding

Biological Process: activation of JNK activity; activation of NF-kappaB transcription factor; B cell proliferation; inflammatory response; isotype switching; negative regulation of apoptosis; platelet activation; positive regulation of interleukin-10 production; positive regulation of interleukin-12 production; positive regulation of interleukin-4 production; positive regulation of T cell proliferation; regulation of immune response; T cell costimulation; tumor necrosis factor-mediated signaling pathway

Disease: Immunodeficiency With Hyper-igm, Type 1