Analysis of the oligomeric requirement for signaling by CD40 using soluble multimeric forms of its ligand, CD154.
We describe the construction of a novel soluble dodecameric form of CD154 (CD40 ligand) that is more effective than trimeric tCD154 in triggering B cell activation. Dodecameric surfactant protein (SP)-D-CD154 was more potent than tCD154 in inducing B cell proliferation over a wide range of concentrations. At saturating concentrations, the level of proliferation triggered by SP-D-CD154 was fourfold higher than that achieved with tCD154. Moreover, stimulation with dodecameric CD154 induced higher levels of the costimulatory molecules ICAM-1 and CD86. The higher activity of dodecameric CD154 when compared to trimeric CD154 is unlikely to be due to differences in their avidity for CD40, since both forms bound to CD40 strongly. Therefore, the extent of receptor clustering directly regulates signaling by CD40.
Haswell
L E
LE
Tenovus Research Laboratory, Cancer Sciences Division, The School of Medicine, University of Southampton, Southampton General Hospital, Southampton, GB.
Glennie
M J
MJ
Al-Shamkhani
A
A
D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D051940:B7-2 Antigen; D019013:CD40 Antigens / Q000502:physiology*; D023201:CD40 Ligand / Q000737:chemistry / Q000502:physiology*; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000032:analysis; D051379:Mice
D015703:Antigens, CD; D051940:B7-2 Antigen; D019013:CD40 Antigens; C497965:Cd86 protein, mouse; D000949:Histocompatibility Antigens Class II; D008562:Membrane Glycoproteins; D018799:Intercellular Adhesion Molecule-1; D023201:CD40 Ligand