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Blockade of CD40-CD40 ligand protects against renal injury in chronic proteinuric renal disease.

BACKGROUND: Interaction between CD40 and CD40 ligand (CD40L) is involved in both cognate and innate immune responses. Blockade of CD40-CD40L interactions reduces severity of renal injury in murine lupus nephritis and membranous nephropathy. We hypothesized that CD40-CD40L could contribute to renal injury in models that are not antibody-dependent, and that anti-CD40L could diminish inflammation and fibrosis in murine adriamycin nephropathy. METHODS: Male BALB/c mice were divided into three groups (N = 6 per group): (1). saline-treated, age-matched control; (2). adriamycin only; and (3). MR1 + adriamycin. In group 3, mice were treated with intraperitoneal injections of anti-CD40L antibody (clone MR1, 0.4 mg per mouse) after the onset of proteinuria at days 5, 7, 9, and 11 after adriamycin treatment. Animal subgroups were compared at 14 and 42 days after induction of adriamycin nephropathy. Functional and pathologic markers of disease severity, cellular components of interstitial inflammation, and the degree of CD40 expression were assessed. Relative cortical RNA expression of the chemokine monocyte-chemoattractant protein-1 (MCP-1) and regulated on activation normal T cell expressed and secreted (RANTES) was also compared between animal groups. RESULTS: CD40 was weakly expressed in tubules of normal mice but was expressed in tubules, interstitium, and glomeruli of mice with adriamycin nephropathy in a time-dependent manner. MR1 treatment resulted in a significant attenuation of the severity of adriamycin nephropathy at day 42 [e.g., glomerular sclerosis (%), group 3, 20.1 +/- 4.7 vs. group 2, 30.2 +/- 7.2, P < 0.001]. CD40L blockade significantly reduced tubulointerstitial injury as well [tubular diameter microm), group 3, 42.5 +/- 6.9 vs. group 2, 66.3 +/- 13.7, P < 0.001; and group 1, 37.3 +/- 5.7, P < 0.01; tubular cell height microm), group 3, 16.3 +/- 1.7 vs. group 2, 11 +/- 1.8, P < 0.01; and group 1, 18.2 +/- 1.9, P < 0.01; interstitial volume (%), group 3, 13.9 +/- 5.1 vs. group 2, 26.2 +/- 4.9, P < 0.001; and group 1, 1.3 +/- 0.7, P < 0.001; proteinuria (mg/24 hours), group 3, 1.8 +/- 0.6 vs. group 2, 4.3 +/- 0.8, P < 0.001; and group 1, 0.7 +/- 0.2, P < 0.05; and creatinine clearance microL/min), group 3, 75 +/- 4 vs. group 2, 35 +/- 2, P < 0.001; and group 1, 82 +/- 4, P < 0.01] were also improved by MR1. MR1 treatment also resulted in a significant reduction in the number of cortical macrophages at both 14 and 42 days after adriamycin (P < 0.01). Cortical expression of MCP-1 and RANTES was significantly reduced by MR1 treatment at 42 days after adriamycin (P < 0.01 and P < 0.05, respectively). CONCLUSION: Blockade of CD40-CD40L interaction protects against renal structural and functional injury in this murine model of chronic proteinuric renal disease.

Animals↗

CD40 expression by human monocytes: regulation by cytokines and activation of monocytes by the ligand for CD40.

CD40 is a member of the tumor necrosis factor (TNF) receptor family of cell surface proteins and was originally described as a B cell restricted antigen. Treatment of primary human monocytes with granulocyte/macrophage colony-stimulating factor (GM-CSF), interleukin 3 (IL-3), or interferon gamma (IFN-gamma) resulted in the induction of CD40 mRNA and enhancement of cell surface protein expression. CD40 was found to mediate monocyte adhesion to cells expressing recombinant CD40 ligand. CD40 ligand-transfected cells provided a potent costimulus for monocyte TNF-alpha and IL-6 production in the presence of GM-CSF, IL-3, or IFN-gamma, and enhanced IL-8 production stimulated by GM-CSF or IL-3. In addition, CD40 ligand-transfected cells acting in the absence of a costimulus induced monocytes to become tumoricidal against a human melanoma cell target. Collectively, these data indicate that CD40 ligand is pleiotropic with potent biological activity on monocytes.

Animals↗

Memory B cell development but not germinal center formation is impaired by in vivo blockade of CD40-CD40 ligand interaction.

To study the role of the CD40-CD40 ligand interaction in the development of memory B cells and its level of action during primary antibody responses in vivo, mice were injected with a soluble CD40 fusion protein (sCD40-gamma 1), so as to block the interaction. The effects of the treatment on the primary antibody response were reminiscent of hyper-immunoglobulin M (IgM) syndrome (HIMG1): antigen-specific IgG responses were grossly inhibited whereas the IgM response was augmented severalfold. The latter observation suggests that there is a T-dependent, CD40 ligand-independent pathway of B cell activation that leads to IgM responses and that a significant component of the IgM in HIMG1 patients is derived from T-dependent responses. The secondary response was not readily blocked by sCD40-gamma 1 treatment, indicating a relative independence of CD40 ligation of antigen-experienced B cells. The most striking finding from these studies is that the development of memory B cell populations (measured by adoptive transfer) is grossly impaired by administration of sCD40-gamma 1 during the early induction phase of the response. It is surprising that although the generation memory is diminished, there is no quantitative difference in the development of germinal centers. Whereas entry of B cells into the memory cell pathway is dependent on CD40 ligation, the clonal expansion of the potential memory precursors in germinal centers seems not to require a CD40 signal.

Animals↗

A new mechanism of NK cell cytotoxicity activation: the CD40-CD40 ligand interaction.

NK recognition is regulated by a delicate balance between positive signals initiating their effector functions, and inhibitory signals preventing them from proceeding to cytolysis. Knowledge of the molecules responsible for positive signaling in NK cells is currently limited. We demonstrate that IL-2-activated human NK cells can express CD40 ligand (CD40L) and that recognition of CD40 on target cells can provide an activation pathway for such human NK cells. CD40-transfected P815 cells were killed by NK cell lines expressing CD40L, clones and PBL-derived NK cells cultured for 18 h in the presence of IL-2, but not by CD40L-negative fresh NK cells. Cross-linking of CD40L on IL-2-activated NK cells induced redirected cytolysis of CD40-negative but Fc receptor-expressing P815 cells. The sensitivity of human TAP-deficient T2 cells could be blocked by anti-CD40 antibodies as well as by reconstitution of TAP/MHC class I expression, indicating that the CD40-dependent pathway for NK activation can be downregulated, at least in part, by MHC class I molecules on the target cells. NK cell recognition of CD40 may be important in immunoregulation as well as in immune responses against B cell malignancies.

CD3 Complex↗

Coexpression of CD40 and CD40 ligand in Epstein-Barr virus-infected T and NK cells and their role in cell survival.

We investigated the role that CD40-CD40 ligand (CD40L) signaling plays in survival of Epstein-Barr virus (EBV)-infected T and NK cells. EBV-infected T and NK cell lines derived from patients with either chronic active EBV infection (CAEBV) or nasal T/NK cell lymphoma, as well as virus-infected peripheral T cells freshly isolated from a patient with CAEBV, were shown to express both CD40 and CD40L on their surface. Apoptosis of these cells was enhanced by blockade of CD40-CD40L signaling by a fusion protein of CD40 and immunoglobulin G (CD40Ig). Expression of CD40 was induced in human CD40L-positive Jurkat T cells after experimental EBV infection, and apoptosis of infected cells was enhanced by CD40Ig. These results suggest that CD40-CD40L signaling promotes survival of EBV-infected T and NK cells and, thus, plays an important role in the pathogenesis of T/NK lymphoproliferative disorders associated with the virus.

CD40 Antigens↗

Disruption of CD40-CD40 ligand pathway inhibits the development of intestinal muscle hypercontractility and protective immunity in nematode infection.

In our previous studies, we demonstrated that during Trichinella spiralis infection, T helper (Th) 2 cells contribute to the development of intestinal muscle hypercontractility and worm expulsion from the gut via STAT6. In addition, we have linked the altered muscle contractility to the eviction of the parasite and thereby to the host defense. However, the initial events linking infection to the development of muscle hypercontractility are poorly understood. In this study, we examined the contribution of CD40-CD40 ligand (CD40L) interaction in the development of intestinal muscle hypercontractility, in monocyte chemoattractant protein-1 (MCP-1) production, and in the Th2 response in CD40 ligand-deficient (CD40L -/-) mice infected with T. spiralis. Expulsion of intestinal worms was substantially delayed in CD40L -/- mice compared with the wild-type mice after T. spiralis infection. Consistent with delayed worm expulsion, there was a significant attenuation of intestinal muscle contractility in CD40L -/- mice. Infected CD40L -/- mice also exhibited marked impairment in the production of MCP-1, IL-4, IL-13, IgG1, IgE, and mouse mucosal MCP 1 (MMCP-1), and in goblet cell response. These results demonstrate that CD40-CD40 ligand interaction plays an important role in MCP-1 production, Th2 response, intestinal muscle hypercontractility, and worm expulsion in nematode infection. The present data suggest that the early events leading to the generation of Th2 response include CD40-CD40 ligand interaction, which subsequently influences the production of Th2 cytokines, most likely via upregulation of MCP-1.

Animals↗

Enhancement of tumoricidal activity of alveolar macrophages via CD40-CD40 ligand interaction.

CD40-CD40 ligand (CD40L) interaction was originally defined as important molecules for the development of humoral immunity. Thereafter, some investigations have focused on its essential roles for the induction of cell-mediated immunity in host defenses. Here we investigated the antitumor activity of murine alveolar macrophages through CD40-CD40L interaction. The CD40L gene was transfected into murine lung cancer cells (3LLSA), and CD40L-expressing clones (3LLSA-CD40L) were established. Stimulation of CD40 molecules on the surface of alveolar macrophages with 3LLSA-CD40L cells induced the production of nitric oxide, tumor necrosis factor-alpha, and interleukin-12 and the tumoricidal activity of alveolar macrophages in the presence of interferon-gamma, which increased the surface expression of CD40 molecules on alveolar macrophages. These findings were not observed when alveolar macrophages were obtained from CD40-deficient mice. On the other hand, interleukin-6 production by alveolar macrophages did not depend on CD40-CD40L interaction. We also established a murine melanoma cell line expressing CD40L (B16 4A5-CD40L) that could induce tumoricidal activity of alveolar macrophages. Furthermore, when spleen cells were cocultivated with 3LLSA-CD40L cells, specific cytotoxic T lymphocytes for wild-type 3LLSA cells could be induced. These results suggest that CD40L gene transfer into tumor cells may induce antitumor immunity in a tumor-bearing host and may offer a new strategy for cancer gene therapy.

Animals↗

Upregulation of CD40 and CD40 ligand (CD154) in patients with moderate hypercholesterolemia.

BACKGROUND: Hypercholesterolemia, a risk factor for cardiovascular disease, is associated with inflammation and hypercoagulability. Both can be mediated by the CD40 system. This study investigated whether the CD40 system is upregulated in patients with moderate hypercholesterolemia and whether it is influenced by therapy with a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor. METHODS AND RESULTS: Fifteen patients with moderate hypercholesterolemia and 15 healthy control subjects were investigated. CD154 and P-selectin were analyzed on platelets and CD40 was analyzed on monocytes before and under therapy with the statin cerivastatin by double-label flow cytometry. Blood concentrations of soluble CD154 and monocyte chemoattractant protein-1 (MCP-1) were evaluated. Our main findings were as follows. Patients with moderate hypercholesterolemia showed a significant increase of CD154 and P-selectin on platelets and CD40 on monocytes compared with healthy subjects. Soluble CD154 showed a nonsignificant trend for higher plasma levels in patients. A positive correlation was found for total or LDL cholesterol and CD154, but not for CD40 on monocytes. The latter was upregulated in vitro by C-reactive protein, which was found to be significantly elevated in patients with moderate hypercholesterolemia. CD154 on platelets proved to be biologically active because it enhanced the release of MCP-1, which was markedly elevated in an in vitro platelet-endothelial cell coculture model and in the serum of patients. Short-term therapy with a HMG-CoA reductase inhibitor significantly downregulated CD40 on monocytes and serum levels of MCP-1. CONCLUSION: Patients with moderate hypercholesterolemia show upregulation of the CD40 system, which may contribute to the known proinflammatory, proatherogenic, and prothrombotic milieu found in these patients.

Adult↗

Th2-dependent B cell responses in the absence of CD40-CD40 ligand interactions.

CD40 is thought to play a central role in T cell-dependent humoral responses through two distinct mechanisms. CD4+ T helper cells are activated via CD40-dependent Ag presentation in which CD80/CD86 provides costimulation through CD28. In addition, engagement of CD40 on B cells provides a direct pathway for activation of humoral responses. We used a model of adenovirus-mediated gene transfer of beta-galactosidase (lacZ) into murine lung to evaluate the specific CD40-dependent pathways required for humoral immunity at mucosal surfaces of the lung. Animals deficient in CD40L failed to develop T and B cell responses to vector. Activation of Th2 cells, which normally requires CD40-dependent stimulation of APCs, was selectively reconstituted in CD40 ligand-deficient mice by systemic administration of an Ab that is agonistic to CD28. Surprisingly, this resulted in the development of a functional humoral response to vector as evidenced by formation of germinal centers and production of antiadenovirus IgG1 and IgA that neutralized and prevented effective readministration of vector. The CD28-dependent B cell response required CD4+ T cells and was mediated via IL-4. These studies indicate that CD40 signals to the B cells are not necessary for CD4+ Th2 cell-dependent humoral responses to be generated.

Adenoviridae↗

[Effect of antisense CD40 RNA on CD40 expression and proliferation of EB virus-transformed B lymphocytes].

AIM: To investigate the changes of CD40 expression and proliferation pattern of EB virus-transformed B lymphocytes that had been transfected by antisense CD40 RNA. METHODS: Eukaryotic expression vector pcDNA3/CD40 of human CD40antisense RNA was constructed by means of T-A cloning and subcloning, and then was transfected into EB virus-transformed B lymphocytes. Changes of CD40 expression on the B cells and their proliferation were tested by flow cytometry and MTT colorimetry assay, respectively. RESULTS: CD40 expression and proliferation of the B cells transfected with antisense CD40 RNA were significantly lower than those of the cells transfected with pcDNA3 alone (P < 0. 01). CONCLUSION: Antisense CD40 RNA may be served as an effective means of regulating immune function, and the CD40 gene itself also play an important role in cell proliferation.

B-Lymphocytes↗

Cyclic-AMP modulates downstream events in CD40-mediated signal transduction, but inhibition of protein kinase A has no direct effect on CD40 signaling.

The role of cAMP/protein kinase A (PKA) in CD40 signal transduction is controversial, with evidence both for and against its importance. In this study we have used a tetracycline-repressible expression system to reversibly express a dominant-negative form of the PKA regulatory subunit type I (PKA-R(G324D)) in a B lymphoma line, M12. Expression of PKA-R(G324D) in M12 lymphomas inhibits both cAMP-mediated growth inhibition and cAMP-mediated induction of B7-2. This inhibition is reversed by tetracycline treatment of the cells to turn off inhibitor expression. In contrast, the expression of the PKA-R(G324D) subunit has no effect on CD40-mediated growth inhibition in M12 cells, nor on CD40-mediated induction of B7-1, CD23, Fas, ICAM-1, or LFA-1. Thus, our data do not support a direct role for cAMP/PKA in CD40-mediated signal transduction. However, we do observe that cAMP can regulate CD40 signaling both positively and negatively. Cyclic-AMP synergizes with CD40-mediated B7-1 induction in M12 lymphomas, while inhibiting CD40-mediated CD23, Fas, and ICAM-1 induction.

Adjuvants, Immunologic↗

Expression of B7 (CD80) and CD40 antigens and the CD40 ligand in Hodgkin's disease is independent of latent Epstein-Barr virus infection.

Aim-To examine the expression of CD40 and B7 (CD80) antigens and the CD40 ligand in Hodgkin's disease.Methods-Antigen and ligand expression was studied in 17 cases of Hodgkin's disease using immunohistochemistry. The study included 11 cases of Hodgkin's disease in which latent Epstein-Barr virus (EBV) infection could be demonstrated within tumour cells by in situ hybridisation for the EBV encoded early RNAs (EBERs).Results-In all cases, irrespective of EBV status, Reed-Sternberg cells and their variants (HRS cells) showed strong expression of both B7 and CD40 antigens. CD40 ligand expression was not shown in HRS cells but was confined to a subset of small lymphocytes some of which were seen to be in intimate contact with HRS cells.Paraffin wax sections from a further 60 cases of Hodgkin's disease were examined for CD40 and EBER expression alone. The CD40 antigen was identified in HRS cells in all of these cases irrespective of EBER expression.Conclusions-As CD40 and B7 expression are features of professional antigen presenting cells, these results provide further evidence that HRS cells may have antigen presenting properties and that this may contribute to the characteristic recruitment and activation of non-malignant lymphocytes which is a feature of Hodgkin's disease. The ability of HRS cells to activate T(h) cells may in turn contribute to their own survival through the induction of the gp39/CD40 pathway.

Journal Article↗

Normal CD40-mediated activation of monocytes and dendritic cells from patients with hyper-IgM syndrome due to a CD40 pathway defect in B cells.

Patients with X-linked hyper-IgM syndrome [CD40 ligand (CD40L) deficiency] are prone to infections by intracellular parasites. It has been suggested that this susceptibility is caused by defective macrophage activation through the CD40L-CD40 pathway. We studied the CD40-mediated activation of monocytes and dendritic cells from patients affected with a CD40L+ hyper-IgM syndrome characterized by a defect of B lymphocyte responses to CD40 agonists. We show that the CD40-induced production of IL-6, IL-8 and TNF-alpha by monocytes, and IL-12 by dendritic cells, and expression of the activation markers CD83, the costimulatory molecules CD86 and CD80, and HLA-DR antigens were all similar in patient and control cells. This observation is consistent with the clinical characteristics of the syndrome: a defect of immunoglobulin switch but no susceptibility to opportunistic infections, as observed in CD40L-deficient patients. These observations suggest that CD40-mediated activation pathways could be, at least in part, different in B and monocytic/dendritic cell lineages.

Antigens, CD↗

Increased levels of CD40-CD40 ligand system in patients with essential hypertension.

BACKGROUND: Although it has been hypothesized that hypertension is in part an inflammatory disorder, clinical data linking inflammation with incident hypertension are scarce. There is evidence that have shown that CD40-CD40L interaction plays a pathogenic role in inflammatory disorders. We assessed whether CD40 system expressions were altered in patients including 30 with hypertension grade 1, 80 with hypertension grade 2 and 40 with hypertension grade 3. METHODS: Twenty normal controls and 150 patients with essential hypertension were investigated. The expression of CD40 and CD40L on platelet was analyzed by indirect-immunofluorescence flow cytometry and soluble CD40L level was determined by a commercially available ELISA. C-reactive protein was also measured by ELISA. RESULTS: All patients with hypertension showed a significant increase of CD40 (67.1+/-9.6 Mean Fluorescence Intensity, MFI) and CD40L (15.3+/-5.0 MFI) coexpression on platelets as well as sCD40L levels (12.8+/-3.9 ng/ml ) compared with controls (p<0.0001). We found that CRP levels related to CD40-CD40L system. We also observed a slight correlation between sCD40L level and blood pressure. During 3 months follow-up, patients with enhanced levels of sCD40L (>15 ng/ml) indicated a tough control of blood pressure. CONCLUSION: Patients with essential hypertension show increased coexpression of CD40 system, which suggests that hypertension is in part an inflammatory disorder.

Adult↗

CD40-CD40 ligand interactions in experimental allergic encephalomyelitis and multiple sclerosis.

We investigated the role of CD40-CD40 ligand (CD40L) interactions in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). Activated helper T cells expressing CD40L (gp39) surface protein were found in MS patient brain sections, but not in brain tissue sections of normal controls or patients with other neurological disease. CD40L-positive cells were co-localized with CD40-bearing cells in active lesions (perivascular infiltrates). Most of these CD40-bearing cells proved to be of the monocytic lineage (macrophages or microglial cells), and relatively few were B cells. To functionally evaluate CD40-CD40L interactions, EAE was elicited in mice by means of proteolipid-peptide immunization. Treatment with anti-CD40L monoclonal antibody completely prevented the development of disease. Furthermore, administration of anti-CD40L monoclonal antibody, even after disease onset, shortly before maximum disability score was reached led to dramatic disease reduction. The presence of helper T cells expressing CD40L in brain tissue of MS patients and EAE animals, together with the functional evidence provided by successful experimental prevention and therapy in an animal model, indicates that blockade of CD40-CD40L-mediated cellular interactions may be a method for interference in active MS.

Animals↗

The central role of the CD40-ligand and CD40 pathway in T-lymphocyte-mediated differentiation of B lymphocytes.

This review summarizes recent findings concerning the role of CD40-ligand and CD40 interactions in B-cell differentiation. CD40-ligand on helper CD4+ T lymphocytes interacts with CD40 on B cells and directs the selection and differentiation of clones of B lymphocytes to generate specific antibody-dependent immune responses. CD40-ligand is necessary for normal B-cell differentiation and plays several distinctive roles in this multistage process. The CD40 signaling pathway that normally regulates B-cell death appears to be usurped by the Epstein-Barr virus to mediate B-cell transformation.

B-Lymphocytes↗

The proportion of CD40+ mucosal macrophages is increased in inflammatory bowel disease whereas CD40 ligand (CD154)+ T cells are relatively decreased, suggesting differential modulation of these costimulatory molecules in human gut lamina propria.

BACKGROUND: Signal transduction through binding of CD40 on antigen-presenting cells and CD40 ligand (CD154) on T cells appears to be crucial for mutual cellular activation. Antibodies aimed at blocking the CD40-CD154 costimulatory pathway dampen the severity of experimental colitis. To elucidate the microanatomical basis for signaling through this costimulatory pathway in human inflammatory bowel disease, we studied in situ the cellular distribution of these 2 molecules on lamina propria macrophages and T cells, respectively. METHODS: Colonic specimens from 8 patients with ulcerative colitis and 8 with Crohn's disease, 8 small bowel specimens of Crohn's disease, and histologically normal control samples (6 from colon and 6 from small bowel) were included. Multicolor immunofluorescence in situ staining was performed to determine the percentage of subepithelial macrophages expressing CD40 and that of lamina propria T cells expressing CD154 while avoiding cells in lymphoid aggregates. RESULTS: The proportion of subepithelial CD40CD68 macrophages was significantly increased in normal colon compared with normal small bowel and showed further elevation in both colon and small bowel afflicted with inflammatory bowel disease. In addition, on a per-CD68-cell basis, CD40 expression was significantly increased in severely inflamed compared with moderately inflamed colonic specimens. Conversely, the proportion of CD154 T cells was similar in colon and small bowel, and interestingly, it was significantly reduced in colonic inflammatory bowel disease. CONCLUSIONS: Our findings suggested that modulation of CD40 expression by subepithelial macrophages and CD154 by lamina propria T cells is inversely modulated in the human gut.

Adolescent↗

Enhancement of binding activity of soluble human CD40 to CD40 ligand through incorporation of an isoleucine zipper motif.

AIM: To investigate the effect of incorporation of an isoleucine zipper (IZ) motif into CD40 on binding activity of CD40 for the CD40 ligand (CD40L). METHODS: Prokaryotic expression vectors for 2 soluble CD40 derivatives, shCD40His and shCD40IZ containing an IZ domain, were constructed and expressed in Escherichia coli. The recombinant proteins were purified to homogeneity after refolding from inclusion bodies. Their molecular weights in solution of shCD40His and shCD40IZ were compared by size-exclusion chromatography, and their binding activity for CD40L on Jurkat T cells was determined by flow cytometry. RESULTS: shCD40His and shCD40IZ were generated. Both of them possessed significant binding activity for the cognate ligand CD40L expressed on the cell surface. shCD40IZ had much higher binding activity to its ligand (CD40L) than did shCD40His. Furthermore, size-exclusion chromatography demonstrated that shCD40IZ existed in high molecular mass forms that were most likely to be trimers in solution. CONCLUSION: Incorporation of an IZ motif into CD40 enhances its binding activity for CD40L through trimerization of the CD40 derivative.

Binding, Competitive↗