Objective To study the immunoregulatory ability of mesenchymal stem cell (MSC) on T cells. Methods MSC were isolated and cultured from bone marrow and CD3 + T cells from peripheral blood. Then the action of MSC on T cell proliferation was investigated. ELISA assay tested IFN-? and IL-10 secretion of CD3 + T cells. Results The data showed that MSC inhibited T cell proliferation in a dose dependent manner when there was 2?10 5/well (96-well plate) CD3 +T cells. While MSC stimulated T cell proliferation when there was 5?10 4/well CD3 + T cells. High dose CD3 +T cells produced high level IFN-? and IL-10 in the absence of MSC, while when there were MSC in the culture, 5?10 4/well CD3 +T cells secreted more IFN-? and IL-10 than 2?10 5/well CD3 + T cells. Conclusion The result suggested that the effect of MSC on T cells was complex, not only correlating with the cell concentration of MSC but also of T cells.

IL-2 gene was introduced into human erythroleukemic cell line K562 by retroviral vector. After transduction for eighteen days, flow microfluorometric analysis for DNA distribution of both K562/neo and K562/IL-2 cells indicated that transduced cells were accumulated in a state of G2M arrest. Thirty days later, the number of G2+M in K562/neo cells decreased, but proportion of G0/G1 in K562/IL-2 cells was still lower and G2+M was higher than that of nontransduced cells. The proliferative activity assay by MTT method demonstrated that the proliferation of K562/IL-2 was slow following four day culture. The index of mitosis was decreased. The results of light microscopical studies showed many giant and multinucleate giant cells with even more than twenty nuclei in each cell. It was possible that the formation of multinucleate giant cells associated with repeated endomitosis in a single cell. Further analysis of morphometry confirmed that the size of IL-2 gene modified K562 cells was increased. The ratio of giant cells was higher than that of nontransduced K562 cells. We suggested that I1-2 gene transduction might have some regulation effects on proliferative activity of K562 cells. IL-2 gene modified K562 cells might be blocked at a stage of G2.

Objective: To study the relationship between mental health and achievement motivation of undergraduates. Method: 532 undergraduates completed SCL-90 and Academic Achievement Motive Scale. Results:17.29% subjects had mental problems. Undergraduates had higher score in self-oriented motive than society-oriented motive, while the score of SCL-90 correlated positively with score in society-oriented motive. In students with poor academic achievement, the score of SCL-90 negatively correlated with score in self-oriented motive. Conclusion:Society-oriented motive had negative influence on mental health of undergraduates and in those with poor academic achievement, poor mental health positively correlated with lower self-oriented motive.

To develop the methodology to purify and culture expand mesenchymal stem cells (MSC) from human bone marrow and investigate the optimal system for MSC differentiation into chondrocytes mononuclear cells were harvested by gradient centrifugation on Percoll at density of 1 073g/ml and seeded in low glucose DMEM containing 10% fetal calf serum. The purity of cells was evaluated by flow cytometric technique. MSC of 2 passages thereafter were absorbed into a biomaterial of gelatin sponge and induced to differentiate in to chondrocytes for one week under the influence of TGF ? and other inductive agents. The feature of chondrocytes in engineered tissues was identified by toluidine blue staining at various time points. The results showed that human mesenchymal stem cells culture expanded were positive for CD166, CD29, and CD44, but negative for CD34, CD45, and HLA DR. Furthermore, when treated cells absorbed into the biomaterial were implanted subcutaneously into BALB c nude mice, they formed cartilage like tissues after 4 weeks.Our conclusions is that cultured marrow MSC have unique biological features and the capacity to differentiate into chondrocytes in vivo , so they are useful for cartilage engineering by serving as the seed cells.

BACKGROUND: There are several types of endogenons stem/progenitor cells in lung that develop from either endoderm or mesoderm precursors.To elucidate the characteristics of the intrapulmonary stem ceils wig help to understand their biological behavior in lung injury.OBJECTIVE: To isolate the mesenchymal stem cells (MSCs) from mouse lung tissues,and identify their morphology and growth characteristics,cell surface antigens,differentiation potential in vitro,stem cell properties,and to investigate the protective role in bleomycin challenged lung.DESIGN,TIME AND SETTING: The present randomized controlled in vivo animal experiment based on in vitro observation of cytology was performed at the Laboratory of Cell Biology,Institute of Basic Medical Science,the Academy of Military Medical Science between October 2005 and August 2007.MATERIALS: Male(3-4 weeks) and female C57BL/6 (6-8 weeks) mice were used.Twenty female C57BL/6 mice were randomly and evenly divided into a pulmonary MSCs (PMSCs)-treated group and a myelosuppression group.METHODS: The lungs from male C57BL/6 mice were digested with collagenase Ⅱ,followed by centrifugation over a Ficoll step.The interface fraction was collected and cultured by adherent method.When the monolayer of adherent cells reached 70%-80%confluence,the adherent cells were detected and expanded in culture medium.The mice in the PMSCs-treated and myelosuppression groups were intraperitoneally administered busulfan to inhibit the immigration of bone marrow stem cells.In addition,pulmonary fibrosis injury was induced in these mice with bleomycin.The PMSCs-treated group was intravenously administered 5×105 PMSCs.At the same time,the myelosuppression group received 100 μ L of phosphate buffered saline.After 14 days,the lungs were taken to prepare paraffin-embedded section.MAIN OUTCOME MEASURES: Cell morphology,immunophenotype,specific markers of the induced cells,expression of gene peroxisome proliferator activated receptor γ,osteopontin,osteocalcin,prosurfactant protein C(SP-C),Oct-4 and Nanog,histological alteration of lung tissue sections.RESULTS: MSCs were successfully isolated from mouse lung tissue.The pulmonary MSCs(PMSCs) were fibroblast-like cells,and expanded rapidly in vitro for up to 40 passages.The phenotype of the PMSCs was Scu- 1+ ,CD44+ ,CD29+ ,CD105+ ,CD54+ ,CD34-,CD45-,CD11b,c-kif,and CD31.They did not express alveolar epithelial cell specific markers,such as SP-C,aquaporin-5,and clara cell secretory protein.It was noticeable that stem cell markers octamer-binding transcription factor 4 (Oct-4) and Nanog were expressed continuously in culture expanded cells.They could differentiate into adipocytes,osteoblasts and alveolar epithelial cells in vitro.Colony-forming assay demonstrated that the colony forming efficiency of the PMSCs was nearly 3%.The cells from single colony were capable of differentiating to osteocytes,adipocytes and alveolar epithelial cells.Intravenous administration of PMSCs could alleviate pulmonary injury and fibrosis induced by bleomycin,despite the bone marrow was intact or not.CONCLUSION: The PMSCs are able to extensively propagate in vitro,can efficiently switch to both mesenchymal and alveolar epithelial lineages in vitro,generate adipocytes,osteocytes,and the alveolar epithelial cells,and reduce pulmonary injury and fibrosis in bleomycin challenged lung in vivo,strongly suggesting their promising applications in cellular therapy against the lung injury.

Objective: This study was aimed to explore antitumor responses induced by recombinant vaccinia viruses expressing a point mutant p53 (rVV-p53FL) and enhancive effects of recombinant vaccinia viruses expressing costimulatory molecule B7 (rVV-B7). Methods: A 135 Cys to Tyr point mutant p53 protein was used as the model of tumor associated antigen. rVV-of3FL and rVV-B7 were used as vaccines to test their induction of CTLs and antitumor immunity. Results: Immunization BABL/c mice with rVV-p53FL could elicited specific CD8+ CTLs that could effecively lyse P815-mp53 cells, a transfectant of the murine P815 mastocytoma containing the mutant p53 gene. Treatment with rVV-p53FL could survive a part of mice challenged with 1 ? 106 P815-mp53. Treatment with rVV-p53FL could significantly prolong survival of tumor-bearing force. Admixture at 1: 1 ratio of rVV-p53FL and rVV-B7 could enhance therapeutic antitumor effects of rVV-p53FL. ~Conclusion: Mutant P53 over-expressed in tumor cells can render cells targets for specific CTLs generated by immunization with mutant p53 protein based vaccine. Costimulatory molecule H7 can enhance tumor-associated antigen inducing antitumor responses.

Transfer of drug resistance genes into hematopoietic cells is an attractive approach to protect hematopoietic system from the toxic effects by chemotherapeutic agents in cancer patients. In this study, transduction of mdr-1 in combination with dihydrofolate reductase (dhfr) gene was performed, and the expression of exogenous genes and chemoprotection capacity in mouse bone marrow cells were observed. The results showed that approximately 15% of bone marrow cells transfected with the retroviral vector expressed mdr-1 as assayed by flow cytometry. Gene transfer resulted in about 0.9 - 13 fold and 0.5 - 2.6 fold increase in the resistance of CFU-GM to taxol and methotrexate in vitro, respectively (P < 0.05). Moreover, seven months after transplantation to syngeneic mice with mdr-1 and dhfr-transfected bone marrow cells, peripheral blood cells in recipients were still positive for gp170 as evaluated by FACS as well as for mdr-1 and dhfr by PCR amplification. These results indicate that hematopoietic progenitors can be transfected by retrovirus containing mdr-1 and dhfr genes, and that functional drug resistance accompanies their expressions. Furthermore, genetic chimerism might exist in hematopoietic stem cells. In conclusion, transfer and expression of mdr-1 and dhfr genes in bone marrow cells might be applicable in gene therapy research in cancer patients.

Abstract:Objective To investigate the protective effects of blocking CD40/CD40L interactions with human CD40-Ig fusion protein in a murine graft-versus-host disease model.Methods Human CD40 gene extracellular region was inserted into plasmid pIG1, which contains genomic human IgG1 Fc gene. A transient vector containing CD40-Fc fusion gene was transfected into COS-7 cells. The CD40-Ig fusion protein was detected through enzyme-linked immunosorbent assay (ELISA). A constitutive vector was also generated by ligating the CD40-Fc fusion gene into pcDNA3.1 and transfecting it into CHO cells. CD40-Ig was purified by protein A affinity chromatography. SDS-PAGE, Western blot and ligand binding assay were used to identify the qualities of CD40-Ig. Murine acute graft-versus-host disease (GVHD) was induced by intravenous injection of C57BL/6J (H-2b) spleen cells into sub-lethally irradiated BALB/c (H-2d) mice. Protective effects against murine graft-versus-host disease by in vivo administration of CD40-Ig were evaluated.Results Mammalian expression vectors pIG/40Ig and p3.1/40Ig were constructed as described above. Chimeric proteins were expressed in COS-7 and CHO cell culture supernatant and confirmed by ELISA and Western blot. SDS-PAGE showed that fusion proteins had a disulfide-bonded dimeric structure and existed as homodimer. Purified CD40-Ig could bind to CD40L. In vivo administration of CD40-Ig could prevent the development of GVHD and significantly prolong the mean survival time of mice with graft-versus-host disease.Conclusions These results demonstrate that CD40/CD40L interactions play an important role in the pathogenesis of graft-versus-host disease and suggest clinical potential for CD40-Ig in the prevention and treatment of human graft-versus-host disease.

CD40/CD40L, besides B7/CD28, is an alternative important costimulation signal transduction pathway. It plays a pivotal role in T cell activation. Moreover, it may play a critical role at many levels of sensitization and effector phases of allograft rejection. In order to get the fusion protein of human CD40 extracelluar region and IgG 1 Fc fragment, and investigate the potential role of blocking CD40/CD40L costimulation pathway in immunotherapy, total RNA was extracted from human lymphoma cell line Daudi, and CD40 gene extracelluar region was amplified by RT-PCR. The PCR products were inserted into pGEM T Easy vector, and the cloning vector pGE40 was obtained. The DNA sequence was analyzed by automatic DNA sequencer. After sequencing, the transient expressing vector was constructed by inserting correct fragment into pIG vector, which contains the genomic human IgG1 Fc (hinge, CH2 and CH3) gene. Hence the recombinant fusion expression vector was constructed successfully, and named after pIG/40 Ig. Then, COS-7 cells were transfected through DEAE-Dextran/chloroquine method. The CD40-Ig fusion protein expressed in COS-7 cell culture supernatant was identified by sandwich ELISA and Western blot. Result showed that the CD40-Ig fusion protein can be detected by sandwich ELISA in the cell culture supernatant. Western blot analysis also showed that it could react with McAbs of mouse anti-human CD40 G28-5 and mouse anti-human Ig gamma chain. There is only one obvious band at the position of relative molecular weight 50 kD, and it is equivalent to the expected value. Above all, the recombinant fusion expression vector pIG/40 Ig was constructed, and CD40-Ig fusion protein gene was expressed in COS-7 cells successfully. It could be laid a foundation to investigate the potential role of CD40/CD40L pathway as the target of GVHD prevention and therapy.

Bone marrow mesenchymal stem cells (MSCs) are multipotential progenitors of connective tissues and bone marrow stroma as well, which implies the modulatory function of MSCs in hematopoiesis. To clarify the contributions of MSCs to hematopoiesis, the methods for isolation and expansion of MSCs were established and long-term bone marrow cultures were performed using irradiated MSCs as the feeder layer. The results here showed that CD34(+) cells from cord blood formed hematopoietic foci adherent to the monolayer. Furthermore, colony-forming cells remained in the coculture of 5 weeks, indicating the maintenance of long-term culture-initiating cells (LTC-IC). Flow cytometry analysis showed that about 1% of the hematopoietic cells in the culture were positive for CD34 and around 15% were CD41a-positive. It is clear that MSCs maintain LTC-IC in vitro and promote differentiation of hematopoietic progenitors especially into megakaryocytic lineage. The preliminary results here demonstrate that MSCs residing in the bone marrow might be a crucial cellular component in the hematopoietic microenvironment.