Recombinant Soluble Trimeric CD40 Ligand Is Biologically Active

Abstract

CD40 ligand (CD40L) is expressed on the surface of activated CD4+ T cells, basophils, and mast cells. Binding of C40L to its receptor, CD40, on the surface of B cells stimulates B cell proliferation, adhesion and differentiation. A preparation of soluble, recombinant CD40L (Tyr-45 to Leu-261), containing the full-length 29-kDa protein and two smaller fragments of 18 and 14 kDa, has been shown to induce differentiation of B cells derived either from normal donors or from patients with X-linked hyper-IgM syndrome (Durandy, A., Schiff, C., Bonnefoy, J.-Y., Forveille, M., Rousset, F., Mazzei, G., Milili, M., and Fischer, A. (1993) Eur. J. Immunol. 23, 2294-2299). We have now purified each of these fragments to homogeneity and show that only the 18-kDa fragment (identified as Glu-108 to Leu-261) is biologically active. When expressed in recombinant form, the 18-kDa protein exhibited full activity in B cell proliferation and differentiation assays, was able to rescue of B cells from apoptosis, and bound soluble CD40. Sucrose gradient sedimentation shows that the 18-kDa protein sediments as an apparent homotrimer, a result consistent with the proposed trimeric structure of CD40L. This demonstrates that a soluble CD40L can stimulate CD40 in a manner indistinguishable from the membrane-bound form of the protein.

Functional Synergy between CD40 Ligand and HIV-1 Tat Contributes to Inflammation: Implications in HIV Type 1 Dementia

“…Truncated, soluble derivatives of this molecule are secreted/shed from activated cells, and retain the ability to bind and activate CD40, which is a 45-to 50-kDa type I integral membrane glycoprotein and a member of the TNFR superfamily (21,22). Cells known to express CD40 include B cells, dendritic cells, endothelial cells, and macrophages, as well as astrocytes and microglia (23)(24)(25)(26).…”

Increased Synthesis of Anti-Tuberculous Glycolipid Immunoglobulin G (IgG) and IgA with Cavity Formation in Patients with Pulmonary Tuberculosis

“…The binding of CD40L to its receptor, CD40, on the surfaces of B cells stimulates B-cell proliferation, adhesion, and differentiation. A soluble isoform of CD40L has been shown to exist in the circulation, exhibiting full activity in B-cell proliferation and differentiation assays (16). It was reported that the treatment of wild-type CD40 mice with sCD40L fusion protein elicited a pulmonary inflammatory response that was not observed in identically treated CD40 knockout mice (21).…”

Gene transfer of the CD40‐ligand to human dendritic cells induces NK‐mediated antitumor effects against human carcinoma cells

“…Although sCD40L released from activated helper T cells apparently forms homotrimers, lyophilized recombinant human CD40L protein forms primarily monomers, exhibiting only faint biological activity to stimulate CD40-positive cells, such as DC and leukemic B cells. [26][27][28] To overcome the insufficient function of sCD40L to stimulate DC, we investigated whether adenovirus-mediated transduction of the human CD40L gene to DC (CD40L-DC) is efficient approach for the induction of Twenty-four hours after cocultivation, NK cells were washed and replated at a cell density of 2 3 10 5 cells/ml. After 48 hr, the IFNg concentration in culture supernatants was quantified by ELISA.…”