There are multiple types of inhibitory immune cells in tumor. Among these cells, Treg (regulatory T cell) plays an extremely important role in tumor development and progression. Treg exihibits potent inhibitory effects on effector cells by a variety of mechanisms, which might be the the key factor for tumor immune escape. These mechanisms include inhibiting the effector cell function by inhibitory cytokines, killing effector cells by granzyme and profrin, interfering effector cell metabolism, and affecting Treg differentiation and proliferation by regulating the function of dendrtic cells, etc. The research on Treg has provided new strategies for tumor immunotherapy. Tumor immunotherapies targeting Treg and related immunosuppressive factors, such as deleting Treg nonsepcificlly or sepcificlly controling the numbers and functions of Treg, might have a bright future in clinical application.keyword regulatory T cell(Treg); neoplasms; immune escape; immunotherapy

The Renca-bearing mice were treated by combined fibroblast-mediated IL-2 and G-CSF gene therapy. The survival periods of Renca-bearing mice were prolonged markedly and 75% of Renca-bearing mice were cured. The spleens of Renca-bearing mice treated by fibroblast-mediated G-CSF gene therapy were larger than the spleens of other mice. Histologic analysis of tumor showed that there were a number of infiltrating eosinophils. The NK, LAK and CTL activity induced from the splenocytes of the tumor-bearing mice increased siginificantly when the mice were treated by fibroblast-mediated IL-2 gene therapy and the cytotoxicity of macrophages also increased. The results demonstrated that the and - tumor responses might be induced more significantly by combined fibroblast-mediated IL-2 and G-CSF gene therapy and better antitumor effect may be achieved.

Dendritic cells (DC) are antigen presenting cells (APC) that play critical roles in the initiation of T cell response and development of T cell-dependent antibodies in vivo. CD34_+ hematopoietic progenitor cells of bone marrow and peripheral blood can differentiate into DC when cultured with GM-CSF and TNF-? in vitro. In the present study, we cultured monocytes isolated from human peripheral blood with 100ng/ml hGM-CSF and 500U/ml hIL-4 for one week, and then found that a large number of DC with high purity were gengerated. DC expressed MHC I , MHC II and costimuladng moleculers highly on cell surface and cound stimulate proliferation of allogeneic T lymphocytes. Self serum or fetal calf serum are best for generation of DC. When hGM-CSF was used alone, the monocytes differentiated into macrophages but not to DC. TNF-? could induce further maturation of DC when added in late period of the culture. Generation of DC from human peripheral blood may facilitate further studies on DC and their clinical applications.

A main complication of chemotherapy in cancer patients is hematopoiesis suppression. Microenviroment transplantation using bone marrow stromal cells (BMSCs) has been demonstrated to be a potent method in recovery of hematopoiesis in animal models. Based on hematopoiesis-supportive ability of BMSCs and high potency of IL-3 in hematopoiesis stimulation, BMSCs were studied as a cellular delivery system for IL-3 gene transfection to promote hematopoiesis recovery of mice after high dose chemotherapy. BMSCs were transfected with recombinant adenovirous containing murine IL-3 gene(MOI = 10), the level of mIL-3 secreted by gene-modified BMSCs was 110U/ml/10~6 cells/ 24h in vitro. The mice were injected with high dose cyclophosphamide(200mg/kg) i.p. and after 24 hours the IL-3 gene-modified BMSCs(2 x 10~6/mouse) were transplanted intrasplenically. White blood cell counts in peripheral blood of mice received intrasplenic injection of IL-3-BMSCs were kept at a high level within two weeks after chemotherapy. The pathological sections of spleens and bone marrow showed significant recovery of hematopoiesis, compared with that of mice received chemotherapy only. The data indicated the feasibility of IL-3 gene-modified BMSCs transplantation in the acceleration of hematopoiesis recovery after chemotherapy.

After murine fetal liver cells (FLC) were transfected with granulocyte-macrophage colony-stimulating factor (GM-CSF) gene by recombinant adenovirus and intrasplenically transplanted into allogeneic mice, the effects of GM-CSF gene-transfected FLC on the recovery of immune response inhibited by chemotherapy were observed. The number of CD4 + cells and the ratio of CD4 + /CDS + cells from peripheral blood lymphocytes increased significantly. The cytotoxicity of the NK cells and the proliferation response of splenocytes to ConA, LPS elevated markedly, but the same results were not from bone marrow. These data demonstrated that intrasplenic transplantation of GM-CSF gene-transfected FLC could effectively accelerate the recovery of immune response after high-dose chemotherapy.

A geometrical model of L4-L5 lumbar segment was constructed using a three-dimensional graphics software. Four conditions of the degenerated discs, i. e. light degeneration, moderate degeneration, severe degeneration and complete excision degeneration, were simulated with loading situations using finite element method under the condition of appropriate computational accuracy. By applying a vertical load of 378.93 N on L4 vertebral plate, stress nephograms on joint isthmus under four different working conditions were obtained. The results showed that the contacted area of facet joint was influenced by the degree of intervertebral disc degeneration level, which influenced the mises stress on joint isthmus. It was proved that joint isthmus was the important pressure-proof structure of the back of lumbar vertebra, and the stress values and distribution were related to structural stiffness of the back of lumbar vertebra as well as the contact area of facet joint. The conclusion could be the theoretical reference for the analysis of spinal biomechanics and artificial disc replacement as well.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Intervertebral Disc ; pathology ; Intervertebral Disc Degeneration ; Lumbar Vertebrae ; physiopathology ; Models, Anatomic ; Pressure ; Zygapophyseal Joint

Objective: To study the treatment of experimental lung metastasis by intratracheal injection of IL 18 gene recombinant adenovirus. Methods: (1)The mouse IL 18 mRNA was detected by RT PCR, the concentrations of IL 18, associated cytokines in lung lavage and blood were determined by ELISA at different times after intratracheal injection of IL 18 recombinant adenovirus. (2)The lung metastasis nodes, mouse survival period, survival rates were investigated in the treatment of experimental lung metastasis in C57BL/6 mouse model. The NK activity and CTL activity were determined by 51 Cr 4 h release method. Results: (1)The IL 18 mRNA could be detected in lung tissue 6 h after intratracheal use of IL 18 recombinant adenovirus, and the concentrations of IL 18 in lung lavage was higher than that of peripheral blood, and both IL 18 mRNA and IL 18 could not be detected in control groups. (2)Intratracheal use of IL 18 recombinant adenovirus had significant therapeutic effect on experimental lung metastasis with the results of increased CTL and NK activity, and with longer survival period and higher survival rates compared with the control groups. Conclusion: Intratracheal usage of adenovirus vector containing IL 18 gene has therapeutic effect on the lung metastasis, denoting that gene therapy of lung diseases can be done through airway directly with recombinant adenovirus.

Adenoviruses harboring E. coli cytosine deaminase gene (AdCD) were used to transfect murine FBL-3 ery-throleukemia cells in vitro. FBL3 cells infected with AdCD were more sensitive to 5-fluorocytosine (5-FC) than cells infected with a control adenovirus AdLacZ. Further study indicated that this combination therapy (AdCD and 5-FC) killed tumor cells by inducing apoptosis of FBL-3 cells. The supematants from FBL-3 cells treated with AdCD/5-Fc were transferred on the culture system of uninfected (wild - type) FBL-3 cells, the result indicated that only 6.25% of the supernatant could induce significant cytotoxicity on wild type FBL3 cells. The results demonoustrated that bystander effect plays an important role in AdCD-mediated cytotoxicities. Direct injection of AdCD into established subcutaneous FBL3 tumor in mice followed by daily intraperitoneal injection of 5-FC for 10 days was found to inhibit tumor growth significant-

Antitumor effect of combined transfer of suicide gene and cytokine gene was evaluated in the present study. Adenoviruses expressing E. coli. cytosine deaminase (AdCD) and adenoviruses expressing murine interleukin 2 (AdTL2) were used for the treatment of tumor-bearing mice. The mice were inoculated s. c. with FBL-3 leukemia cells and 3 days later received intratumoral injection of AdCD in the presence or absence of AdIL2 followed by intraperitoneal 5-fluorocytosine (5FC) administration. The results demonstrated that tumor-bearing mice treated with AdCD/5FC in combination with AdTL2 showed more .potent inhibition of tumor growth and survived much longer as compared with mice treated with AdCD/5FC, AdEL2, AdlacZ/5FC or PBS. It was illustrated that the tumor mass showed obvious necrosis and inflammatory cell infiltration, and more CD4+ and CD8+ T cells infiltrated into the tumor after combined therapy. The splenic NK and CTL activities increased significantly in mice after combined transfer of CD gene and EH gene. Our results demonstrated that combined transfer of suicide gene and IL-2 gene could inhibit the growth of established tumor in mice significantly and induce antitumor immunity of the host efficiently.

Objective To investigate the mechanisms of tacrolimus on the migration of Langerhans′ cells. Methods The concentration of MCP-1 in the cultured supernatants of HaCaT cell treated with tacrolimus was determined by ELISA. The expression level of MCP-1 mRNA in HaCaT cell treated with tacrolimus was studied by RT-PCR method. Results The concentration of MCP-1 in HaCaT cell treated with 625 ～ 5 000 ng/mL of tacrolimus was significantly decreased. The expression level of MCP-1 mRNA was also markedly decreased. Conclusions Tacrolimus may probably decrease the expression of MCP-1 in keratinocytes and suppress the chemotactic ability of Langerhans′ cells precursor and Langerhans′ cells, thus inhibiting or diminishing certain local immunoreaction.