ABSTRACT
<p><b>OBJECTIVE</b>To study the therapeutic effect of agonistic CD40 monoclonal antibody combined with tumor specific cytotoxic T lymphocyte (CTL) on B lymphoma.</p><p><b>METHODS</b>Human B lymphoma cell line, Daudi cells, were cultured with CD40 mAb (5C11) for 24 and 48 hours, respectively. Annexin V/PI-binding assay was employed to analyze apoptosis, and FCM to analyze Fas (CD95) expression. Human peripheral monocyte-derived DC were loaded with apoptotic Daudi cells and stimulated by SC11 for further maturation. Tumor specific CTL were generated in vitro by co-culture of mature DC with autologous T lymphocytes. DNA fragmentations of Daudi cells treated with 5C11, CTL or 5C11 combined with CTL were determined by JAM assay. To establish the B lymphoma model, Daudi cells were subcutaneously injected into humanized SCID mice (hu-SCID). 1 or 3 weeks after tumor transfer. tumor-bearing mice were respectively treated with SC11, CTL, 5C11 combined with CTL by intraperitoneal injection. Tumor volume in differently treated mice was measured every week after therapy, and the survival of tumor-bearing mice was recorded.</p><p><b>RESULTS</b>5C11 significantly up-regulated FAS expression in Daudi cells, but had no significant effect on apoptosis rate of Daudi cells. Tumor-specific CTL could effectively kill Daudi cells. Fragmentation of Daudi cells co-cultured with CTL was remarkably enhanced by combination with SC11. Tumor growth in hu-SCID mice was apparently delayed by treatment with SC11, CTL, or SC11 combined with CTL. Moreover, minimal tumor burden mice got 30.0% or 70.0% complete remission (CR), respectively, when received CTL treatment or combination treatment of SC11 with CTL, and the lifespan of tumor bearing mice was also prolonged significantly.</p><p><b>CONCLUSION</b>SC11 may enhance the sensitivity of Daudi cells to apoptosis by up-regulation of Fas expression and promote cytotoxicity of CTL in vitro and therapeutic effect in vivo.</p>
Subject(s)
Animals , Female , Humans , Mice , Antibodies, Monoclonal , Allergy and Immunology , Therapeutic Uses , Apoptosis , Allergy and Immunology , CD40 Antigens , Allergy and Immunology , Cell Line, Tumor , Coculture Techniques , Flow Cytometry , Immunotherapy, Adoptive , Methods , Lymphoma, B-Cell , Allergy and Immunology , Pathology , Therapeutics , Mice, SCID , Remission Induction , Survival Analysis , T-Lymphocytes, Cytotoxic , Cell Biology , Allergy and Immunology , Xenograft Model Antitumor Assays , fas Receptor , Allergy and ImmunologyABSTRACT
<p><b>OBJECTIVE</b>To study the impact of an agonist anti-CD(40) monoclonal antibody 5C11 on the induction and biological characteristics of leukemic dendritic cells.</p><p><b>METHODS</b>Combinations of 5C11 and different cytokines were used to induce differentiation of leukemic blasts into dendritic cells. Morphology was observed by light microscopy. Surface antigens of the induced cells were analyzed by fluorescence-activated cell sorting (FACS), the yields of dendritic cell by cell counting, the levels of IL-6 and IL-12 by ELISA, T cell proliferating activity by allo-mixed lymphocyte reaction (MLR) in vitro. Allogeneic T cells were stimulated with leukemic dendritic cells and T-cell cytotoxicity was measured by MTT assay.</p><p><b>RESULTS</b>When cultured with combinations of 5C11 and different cytokines, the leukemic cells isolated from the patients could differentiate into dendritic cells. The morphology showed typical features of dendritic cells, which expressed high levels of CD(40), CD(80) and CD(86). In comparison with the original leukemia cells, the leukemic dendritic cells secreted less IL-6 but more IL-12 (P < 0.05). The leukemic dendritic cells were potent to stimulate the proliferation of allogeneic T cells, and the latter was able to lyse the original leukemia cells.</p><p><b>CONCLUSION</b>Leukemic blasts could be induced to differentiate into functional dendritic cells. It may be of great value in the adoptive immunologic therapy of leukemia.</p>