Heteromultimeric Complexes of CD40 Ligand Are Present on the Cell Surface of Human T Lymphocytes

Hsu, Yen-Ming; Lucci, Jodie; Su, Lihe; Ehrenfels, Barbara; Garber, Ellen A.; Thomas, David W.

doi:10.1074/jbc.272.2.911

Cited by 50 publications

(39 citation statements)

References 40 publications

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“…1 shows that when wild-type CD154 was expressed alone, immunoprecipitates of anti-N-terminal peptide antiserum, Rb784 (lane 3), and anti-CD154 mAb, 5c8 (lane 4), contained primarily the full-length p33 protein, some p31 protein, and a small amount of p18. This is consistent with our previous observation (15). These components were not observed in the immunoprecipitates of anti-Myc mAb, 9E10 (lane 1), or control rabbit antiserum (lane 2).…”

Section: Tnfh(ϫ) Mutant Is Associated Withsupporting

confidence: 93%

“…9E10 monoclonal antibody was produced and purified from culture supernatant of the hybridoma (ATCC). Procedures for engineering, producing, and purifying CD40-Fc fusion protein, humanized 5c8, and rabbit polyclonal antibodies, Rb779 and Rb784, were described previously (15).…”

Section: Methodsmentioning

confidence: 99%

“…Expression of CD154 and its variants were analyzed in cells harvested 72 h after transfection. Metabolic labeling, biotinylation of cell surface proteins, immunoprecipitation, SDS-PAGE, and Western blotting analysis were performed as described (15). Preparation of membrane fractions from transfected COS7 cells and the procedures for analysis of lymphotoxin-␣ up-regulation were described previously (6).…”

Section: Methodsmentioning

confidence: 99%

“…Wild-type protein not complexed with TNFH(Ϫ) mutant are transported to the cell surface, and some are in heterotrimeric forms (15). Wild-type CD154 associated with mutant protein are retained inside the cell.…”

Section: Fig 5 Schematic For How Surface Maturation Of Wild-type CDmentioning

confidence: 99%

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CD154 Variant Lacking Tumor Necrosis Factor Homologous Domain Inhibits Cell Surface Expression of Wild-type Protein

Garber²,

Hsu

2001

Journal of Biological Chemistry

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X-linked hyper-IgM (XHIM) syndrome is an immunological disorder resulting from mutations in the CD154 gene. Some mutations occur in splicing sites and result in transcripts encoding wild-type and mutant proteins. These mutants lack the tumor necrosis factor homologous (TNFH) domain and consequently fail to trimerize. Given that the TNFH domain is responsible for trimerization, one may predict that the TNFH mutant can not participate in the assembly of wild-type CD154. Thus, it was puzzling why these patients exhibit XHIM phenotype, presumably resulting from a lack of functional CD154. One possibility is that the TNFH mutant exhibits a dominant negative effect over the wild-type protein.To investigate this, we coexpressed the wild-type protein and a TNFH mutant and examined the biochemical and functional properties of the resulting CD154 products. We demonstrate that despite the lack of the TNFH domain, the TNFH mutant can associate with the wildtype protein. Furthermore, such an association compromises the ability of the wild-type protein to mature onto the cell surface. These results provide a mechanism for the defect of CD154 in XHIM patients producing both wild-type and TNFH variants and suggest that besides the TNFH domain, the stalk region participates in the assembly of CD154 trimers.CD40 ligand (CD154) is a type II membrane protein expressed primarily on activated T cells. The interaction of CD154 with its receptor, CD40, is critical for the functions of T helper cells to induce differentiation, proliferation, and Ig isotype switching in B cells (for review see Refs. 1 and 2). The CD154 gene, located at Xq2.6 -2.7, spans over 12 kilobase pairs and consists of five exons (3). The first exon encodes the cytoplasmic region, the transmembrane domain, and 6 amino acids of the extracellular domain. The second and third exons encode the extracellular stalk region. The fourth and fifth exons encode the C-terminal 147 amino acids (3), which share a limited homology with other members of the TNF 1 family and is called the TNF homologous (TNFH) domain. The x-ray structure of the CD154 TNFH domain reveals that it contains a sandwichlike fold of two ␤ sheets with jellyroll or Greek key topology and forms a trimer similar to that seen in TNF and lymphotoxin-␣ (4). Given the facts that for CD154, the TNFH domain alone is capable of forming trimers (4, 5) and that deletion mutants missing a major portion of this domain did not trimerize (6), it appeared that the TNFH domain is necessary and sufficient for the assembly of trimeric CD154 protein.Mutations in the CD154 gene can prevent the expression of functional CD154 protein, which lead to an immunodeficiency characterized by an elevated IgM and low IgG and IgA levels in serum called X-linked hyper-IgM (XHIM) syndrome (7-11). Over 70 unique mutations in the CD154 gene have been identified in more than 100 patients (12). These mutations are very heterogeneous and include insertions, deletions, and point mutations. Thus, it is conceivable that the underlying mechanisms res...

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Section: Tnfh(ϫ) Mutant Is Associated Withsupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Fig 5 Schematic For How Surface Maturation Of Wild-type CDmentioning

confidence: 99%

See 2 more Smart Citations

CD154 Variant Lacking Tumor Necrosis Factor Homologous Domain Inhibits Cell Surface Expression of Wild-type Protein

Garber²,

Hsu

2001

Journal of Biological Chemistry

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“…Both cell-surface-bound and soluble forms of CD154 exist as homotrimers (11,12), and soluble platelet-derived CD154 has been shown to mediate endothelial and APC activation in vitro (10,(13)(14)(15). Indeed, CD154 cleaved and released in soluble form after platelet activation has been considered a major source of circulating CD154 (16).…”

Section: Introductionmentioning

confidence: 99%

Platelet-derived or soluble CD154 induces vascularized allograft rejection independent of cell-bound CD154

Zhang²,

Mannon³

et al. 2006

Journal of Clinical Investigation

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CD154 is a cell surface molecule expressed on activated T cells that binds to CD40, an activating molecule on APCs. Its blockade has been shown to prevent allograft rejection, presumably by interrupting interactions between T cells and APCs. It is known that activated human platelets express and shed CD154 and can induce APC activation and other immune processes in vitro. Here we show that platelet-derived CD154 is sufficient to initiate cardiac allograft rejection independent of any cellular source of this molecule. CD154-KO mice reject cardiac allografts after receiving CD154-expressing human platelets or recombinant CD154 (rCD154) trimers. Treatment with the human CD154-specific mAb 5c8 specifically prevents this induced rejection. Soluble trimers, but not platelets, induce rejection when infused temporally remote from the surgical procedure, suggesting that surgically induced platelet activation is required for CD154 release. Allograft rejection can thus be instigated by activated platelets through CD154. These data implicate platelets as a proximal component of acquired alloimmunity, providing insight into the mechanisms of allograft rejection and the physiological response to trauma in general.

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Elevated levels and functional capacity of soluble CD40 ligand in systemic lupus erythematosus sera

Vakkalanka

Woo

Kirou

et al. 1999

Arthritis & Rheumatism

146

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Heteromultimeric Complexes of CD40 Ligand Are Present on the Cell Surface of Human T Lymphocytes

Cited by 50 publications

References 40 publications

CD154 Variant Lacking Tumor Necrosis Factor Homologous Domain Inhibits Cell Surface Expression of Wild-type Protein

CD154 Variant Lacking Tumor Necrosis Factor Homologous Domain Inhibits Cell Surface Expression of Wild-type Protein

Platelet-derived or soluble CD154 induces vascularized allograft rejection independent of cell-bound CD154

Elevated levels and functional capacity of soluble CD40 ligand in systemic lupus erythematosus sera

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