Human native soluble CD40L is a biologically active trimer, processed inside microsomes.
CD40 ligand (CD40L) is a glycoprotein expressed on the surface of activated helper T cells, basophils, mast cells, and eosinophils. Binding of CD40L to its receptor CD40 on the B cell surface induces B cell proliferation, adhesion, and immunoglobulin class switching. We have identified soluble cleavage products of human CD40L in the supernatant of a stimulated human T cell clone. Subcellular fractionation experiments have shown that the transmembrane CD40L is processed inside the microsomes and that its cleavage is stimulation-dependent. The native human soluble CD40L is trimeric and, when used in conjunction with interleukin-4, induces B cell proliferation.
Pietravalle
F
F
Glaxo Institute for Molecular Biology, Geneva, Switzerland.
Lecoanet-Henchoz
S
S
Blasey
H
H
Aubry
J P
JP
Elson
G
G
Edgerton
M D
MD
Bonnefoy
J Y
JY
Gauchat
J F
JF
D001402:B-Lymphocytes / Q000276:immunology; D019013:CD40 Antigens / Q000378:metabolism*; D023201:CD40 Ligand; D002460:Cell Line; D006801:Humans; D008024:Ligands; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D008861:Microsomes / Q000276:immunology / Q000378:metabolism; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology
D019013:CD40 Antigens; D008024:Ligands; D008562:Membrane Glycoproteins; D023201:CD40 Ligand