1ALY, 1I9R, 3LKJ, 3QD695921947ENSG00000102245ENSMUSG00000031132P29965P27548NM_000074NM_011616NP_000065NP_035746CD154, also called CD40 ligand or CD40L, is a protein that is primarily expressed on activated T cells[5] and is a member of the TNF superfamily of molecules.

[7] A defect in this gene results in an inability to undergo immunoglobulin class switching and is associated with hyper IgM syndrome.

[8] Absence of CD154 also stops the formation of germinal centers and therefore prohibiting antibody affinity maturation, an important process in the adaptive immune system.

[10] Randolph Noelle at Dartmouth Medical School generated an antibody that bound a 39 kDa protein on murine T cells and inhibited helper function.

[11] Noelle contested Lederman's patent, but the challenge (called an interference) was rejected on all counts [12] CD40 ligand (CD154) is primarily expressed on activated CD4+ T lymphocytes but is also found in a soluble form.

Early evidence for these effects were that in CD40 or CD154 deficient mice, there is little class switching or germinal centre formation, and immune responses are severely inhibited.