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Recombinant CD40 ligand therapy has significant antitumor effects on CD40-positive ovarian tumor xenografts grown in SCID mice and demonstrates an augmented effect with cisplatin.

CD40 is a member of the tumor necrosis factor receptor family and was first identified with a monoclonal antibody raised against bladder carcinoma. Recombinant human CD40L has been shown previously to have a direct antitumor effect on an ovarian cancer cell line and ovarian carcinoma cells isolated from ascites fluid. We show here that rhuCD40L inhibits the growth of several ovarian adenocarcinomas derived from surgical specimens and grown as xenografts in severe combined immunodeficient mice. Two 14-day treatment cycles were more effective than one. This effect is apparently not mediated by natural killer cells, because blocking natural killer cell activity by antiasialo GM-1 did not diminish this effect. In addition to suppression of tumor growth, treatment with rhuCD40L resulted in an increased expression of FasL, an increase in apoptosis, and histological changes including increased fibrosis and areas of tumor destruction. Using this model, we examined the efficacy of rhuCD40L in combination with chemotherapeutic agents. The antitumor effect of rhuCD40L in combination with 4 mg/kg cisplatin (CDDP) was increased over the effect of CDDP alone. Furthermore, rhuCD40L increased the efficacy of a suboptimal dose of CDDP (2mg/kg) such that it matched that of high-dose CDDP alone. These data suggest a role for rhuCD40L therapy in combination with platinum based regimens for primary treatment of epithelial ovarian tumors.

Animals↗

The CD40-ligand stimulates T-lymphocytes via the neutral sphingomyelinase: a novel function of the CD40-ligand as signalling molecule.

Recent results suggest an activation of T-lymphocytes via the CD40L implying a dual function of this ligand involved in the activation of both B- and T-lymphocytes [1-4]. Here, we provide evidence that activation of T-lymphocytes via CD40L results in activation of a neutral but not an acidic sphingomyelinase correlating with a consumption of sphingomyelin and a release of ceramide. Activation of the neutral sphingomyelinase by the CD40L seems to involve a novel signalling cascade since it is independent of CD40L induced protein kinase activation or association of the neutral sphingomyelinase with the CD40L.

Animals↗

[Study of reducing graft-versus-host disease by in vitro blockade of CD40-CD40 ligand co-stimulatory pathway in allogeneic bone marrow transplantation mouse model].

OBJECTIVE: To investigate the effect and its mechanism of reducing graft-versus-host disease (GVHD) by in vitro blockade of CD(40)-CD(40)L pathway in vitro, the donor T lymphocytes cultured in vitro with anti-CD(40)L mAb were transfused in bone marrow transplantation (BMT) GVHD mouse model. METHODS: C57BL/6(H-2b) spleen T cells were isolated as responder cells, and BALB/c(H-2d) spleen cells as stimulator cells. They were cocultured with or without Anti-CD(40)L mAb as anti-CD(40)L mAb group and control group, respectively. At day 5, the mixed lymphocyte response (MLR)-culture cells mixed with bone marrow cells and transfused respectively into the TBI conditioned recipient mice. The mice were divided into two groups: group A, bone marrow cells (2 x 10(6)) and spleen T lymphocytes (2 x 10(6)) from MLR control group; group B, bone marrow cells (2 x 10(6)) and spleen T lymphocytes (2 x 10(6)) from MLR anti-CD(40)L mAb group. The GVHD incidence and hematopoietic reconstitution were observed. Peripheral blood sera and spleen cells of the recipients mice were harvested at scheduled time points for the measurement of cytokines and T cell immunophenotyping with flow cytometry. RESULTS: The incidence of GVHD in group A was 100% (10/10), and in group B was 20% (2/10). The percentage of H-2D(b) positive cells in group B (n = 8) was (93.54 +/- 2.32)% at day 40 after transplantation. The levels of cytokines in serum from group B were significantly lower than those from group A (P < 0.05). The expressions of CD(4)(+), CD(8)(+), CD(4)(+)CD(25)(+), CD(8)(+)CD(25)(+), CD(4)(+)CD(69)(+), CD(8)(+)CD(69)(+) and CD(4)(+)CD(40)L(+) were lower in group B than in group A (P < 0.05). The expressions of CD(8)(+)CD(40)L(+) and CD(4)(+)CD(45)RA(+) were similar in the two groups (P > 0.05). CONCLUSION: Blockade of CD(40)-CD(40)L interaction in vitro could induce immune tolerance in vivo, reduce aGVHD in aGVHD mice model and form chimerism, which was mediated by inhibiting the Th1 and Th2 cytokines production, inducing tolerance of CD(4)(+) and CD(8)(+) cells to alloantigens. The obstruction of T cells activation after tolerance happened mainly at the early and mature phase of T cells activation. These provided the experimental basis for the use of anti-CD(40)L mAb in the clinical transplantation to prevent aGVHD.

Animals↗

[Anti-CD40 McAb induces CD40+ malignant B cell proliferation arrest and apoptosis].

OBJECTIVE: To study the expression of CD(40) molecule and the biological effects mediated by CD(40) molecules on malignant B cells. METHODS: Agonistic anti-human CD(40) monoclonal antibody (5C11) was added to the cell culture system. Cell counting, PI staining, Annexin-V staining and flow cytometric analysis were used to study the biological effects of 5C11 on malignant B cell lines. RESULTS: 5C11 induced homotypic aggregation, proliferation arrest and apoptosis in the multiple myeloma cell line XG2 highly expressed CD(40). 5C11 induced B lymphoma cell line Daudi homotypic aggregation and proliferation arrest but no apoptosis. CONCLUSION: 5C11 can inhibit proliferation of malignant B cells by inducing apoptosis or arresting the cells at G(2)/M interphase.

Antibodies, Monoclonal↗

Critical role for IL-4 in the development of transplant arteriosclerosis in the absence of CD40-CD154 costimulation.

Blockade of the CD40-CD154 pathway can inhibit CD4(+) T cell activation but is unable to prevent immune responses mediated by CD8(+) T cells. However, even in the absence of CD8(+) T cells, inhibition of the CD40-CD154 pathway is insufficient to prevent the development of transplant arteriosclerosis. This study investigated the mechanisms of transplant arteriosclerosis in the absence of the CD40 pathway. C57BL/6 CD40(-/-) (H2(b)) recipients were transplanted with MHC-mismatched BALB/c (H2(d)) aortas. Transplant arteriosclerosis was evident in both CD40(-/-) and CD40(+/-) mice (intimal proliferation was 59 +/- 5% for CD40(-/-) mice vs 58 +/- 4% for CD40(+/-) mice) in the presence or absence of CD8(+) T cells (intimal proliferation was 46 +/- 7% for CD40(-/-) anti-CD8-treated mice vs 50 +/- 10% for CD40(+/-) anti-CD8-treated mice), confirming that CD8(+) T cells are not essential effector cells for the development of this disease. In CD40(-/-) recipients depleted of CD8(+) T cells, the number of eosinophils infiltrating the graft was markedly increased (109 +/- 24 eosinophils/grid for CD40(-/-) anti-CD8-treated mice vs 28 +/- 7 for CD40(+/-) anti-CD8-treated mice). The increased presence of eosinophils correlated with augmented intragraft production of IL-4. To test the hypothesis that IL-4 was responsible for the intimal proliferation, CD8 T cell-depleted CD40(-/-) recipients were treated with anti-IL-4 mAb. This resulted in significantly reduced eosinophil infiltration into the graft (12 +/- 5 eosinophils/grid for CD40(-/-) anti-CD8(+), anti-IL-4-treated mice vs 109 +/- 24 for CD40(-/-) anti-CD8-treated mice), intragraft eotaxin, CCR3 mRNA production, and the level of intimal proliferation (18 +/- 5% for CD40(-/-) anti-CD8(+)-, anti-IL-4-treated mice vs 46 +/- 7% for CD40(-/-) anti-CD8-treated mice). In conclusion, elevated intragraft IL-4 production results in an eosinophil infiltrate and is an important mechanism for CD8(+) T cell-independent transplant arteriosclerosis in the absence of CD40-CD154 costimulation.

Animals↗

Constitutive activation of extracellular signal-regulated kinase predisposes diffuse large B-cell lymphoma cell lines to CD40-mediated cell death.

CD40 promotes survival, proliferation, and differentiation of normal B cells but can cause activation-induced cell death in malignant B lymphocytes. CD40 ligand and anti-CD40 antibodies have been used successfully to induce apoptosis in lymphoma lines both in vitro and in xenograft tumor models. Although this makes CD40 an attractive target for antitumor therapies, the response of malignant B cells to CD40 signaling is variable, and CD40 stimulation can enhance proliferation and can increase chemoresistance in some cell lines. It would therefore be useful to identify markers that predict whether a specific cell line or tumor will undergo apoptosis when stimulated with CD40 and to identify targets downstream of CD40 that affect only the apoptotic arm of CD40 signaling. We have analyzed gene expression patterns in CD40-sensitive and CD40-resistant diffuse large B-cell lymphoma (DLBCL) cell lines to identify signaling pathways that are involved in CD40-mediated apoptosis. CD40-resistant lines expressed pre-B-cell markers, including RAG and VPREB, whereas CD40-sensitive cells resembled mature B cells and expressed higher levels of transcripts encoding several members of the CD40 signaling pathway, including LCK and VAV. In addition, CD40-sensitive DLBCL cell lines also displayed constitutive activation of extracellular signal-regulated kinase (ERK) and failed to undergo apoptosis when ERK phosphorylation was inhibited. In contrast, CD40-resistant lines showed no constitutive activation of ERK and no increase in ERK activity in response to CD40 stimulation. Our results suggest that constitutive activation of ERK may be required for death signaling by CD40.

Apoptosis↗

The CD40 antigen and its ligand.

CD40 is an integral membrane protein found on the surface of B lymphocytes, dendritic cells, follicular dendritic cells, hematopoietic progenitor cells, epithelial cells, and carcinomas. It is a 45-50 kDa glycoprotein of 277 aa, which is a member of the tumor necrosis factor receptor superfamily. The CD40 gene maps to human chromosome 20q11-2-q13-2. CD40 binds to a ligand (CD40-L) which is an approximately 35 kDa glycoprotein of 261 aa, a member of the tumor necrosis factor superfamily. The CD40-L gene maps to human chromosome Xq24. This CD40-L is expressed on activated T cells, mostly CD4+ but also some CD8+ as well as basophils/mast cells. The CD40-L is defective in the X-linked hyper-IgM syndrome. Cross-linking of CD40 with immobilized anti-CD40 or cells expressing CD40-L induces B cells to proliferate strongly, and addition of IL-4 or IL-13 allows the generation of factor-dependent long-term normal human B cell lines and the secretion of IgE following isotype switching. Addition of IL-10 results in very high immunoglobulin production with limited cell proliferation. IL-10 induces naive B cells to produce IgG3, IgG1, and IgA1, and further addition of TGF beta permits the secretion of IgA2. Several evidences suggest that CD40-dependent activation of B cells is important for the generation of memory B cells within the germinal centers: (i) CD40 activated germinal center B cells cultured in the presence of IL-4 acquire a memory B cell phenotype, (ii) CD40 activated B cells can undergo isotype switching, (iii) the deficit of CD40-L results in the hyper-IgM syndrome characterized by lack of germinal centers in secondary lymphoid organ follicles and lack of IgG, IgA, and IgE, and (iv) CD40-L positive T cells are present in secondary follicles. Thymic epithelial cells, activated monocytes, and dendritic cells express CD40 antigen which may be involved in an enhanced cytokine production by these cells, allowing an amplification of T cell proliferation. Finally, as other members of the tumor necrosis factor receptor family have been shown to bind several ligands, it is possible that CD40 may bind other ligands that may trigger CD40 on different cell types such as hematopoietic cells or epithelial cells.

Amino Acid Sequence↗