ABSTRACT
<p><b>OBJECTIVE</b>To explore the anti-tumor effect and its mechanism of Sendai virus Tianjin strain defective interfering particles (DIP) on mouse models of colon carcinoma.</p><p><b>METHODS</b>CT26 cells (5×10(6)/0.1 ml) were subcutaneously injected into the back of Bal B/c mice to establish murine colon carcinoma model. After the tumors reached 5 mm in diameter, the mice were randomly divided into Tianjin strain DIP group and saline control group. The former was intratumorally injected with Tianjin strain DIP (0.1 ml) once a day on day 4, 7, 10 and 13 after CT26 cell inoculation. The latter was intratumorally injected with the same volume of saline. Tumor volume and survival rate of the mice were calculated to confirm the anti-tumor effect of DIP. Flow cytometry and ELISA were used to examine the maturation and release of cytokines IL-6, IFN-α and TNF-α from murine myeloid dendritic cells (DCs) induced by Tianjin strain DIP. Moreover, real-time RT-PCR and immunohistochemistry were performed to identify whether the Tianjin strain DIP could induce infiltration of CD11c(+) DCs, CD4(+) and CD8(+) T cells in the tumors.</p><p><b>RESULTS</b>On day 22 after CT26 cell inoculation, the average tumor volume of the Tianjin strain DIP group was (33.2 ± 2.0) mm(3), significantly smaller than that of the control group [(2 376.0 ± 130.8)mm(3), P < 0.01]. On day 50 after CT26 cell inoculation, the survival rate of mice was 90.0% in the Tianjin strain DIP group, much higher than that of the control group (30.0%, P < 0.01). Flow cytometry analysis showed that the expression of markers of DCs maturation, including CD40, CD80 and CD86, was dose-dependently increased by DIP or intact virus. No statistically significant difference was found betweent the DIP and intact virus groups. ELISA results showed that DIP could stimulate the secretion of IL-6, IFN-α and TNF-α from mouse DCs. The secretion of all of the cytokines was dose-dependently increased by DIP or intact virus. Real-time RT-PCR revealed that the expression of CD4, CD8 and CD11c mRNAs was increased in tumors treated with DIP compared with that of the saline group at all time points. Moreover, the expression level of all of them remained maximal at 120 h after the last treatment. Immunohistochemical staining revealed that the ratios of CD4(+), CD8(+) T cells or CD11c(+) DCs to total cells were (21.60 ± 1.49)%, (22.12 ± 2.84)% and (23.05 ± 2.91)%, respectively, in the DIP-treated tumors. In the tumors treated by saline, the ratios were (2.62 ± 0.60)%, (4.05 ± 0.12)% and (3.10 ± 0.09)%, respectively. The difference between experimental group and control group had statistical significance.</p><p><b>CONCLUSIONS</b>Tianjin strain DIP may exert anti-tumor effect on tumor-bearing mice. The mechanism is related with the antitumor immunity induced by DCs and T cells.</p>
Subject(s)
Animals , Female , Mice , Cell Line, Tumor , Colonic Neoplasms , Metabolism , Pathology , Cytokines , Metabolism , Defective Viruses , Allergy and Immunology , Dendritic Cells , Metabolism , Interferon-alpha , Metabolism , Interleukin-6 , Metabolism , Mice, Inbred BALB C , Neoplasm Transplantation , Random Allocation , Sendai virus , Allergy and Immunology , T-Lymphocytes , Metabolism , Tumor Burden , Tumor Necrosis Factor-alpha , MetabolismABSTRACT
This article introduced the thoughts and practice of implementing microbiology course reform for stomatology majors in school of stomatology and department of microbiology in Tianjin medical university.To make the introductory courses more suitable and meet the needs of stomatology better,our microbiology classes included the basic knowledge of oral microoganism.
ABSTRACT
Objective To investigate the specific pathogenesis of O-antigen polysaccharide(OPS) which is a subunit component of lipopolysaccharide(LPS) from enteroinvasive Escherichia coli. Methods The OPS was extracted and purified from Escherichia coli O29(enteroinvasive E.coli) strain. Effects of OPS, contrasted with the whole LPS molecule, were observed by in vitro experiments (HeLa cell culture) and in vivo experiments (rabbit ileal loop assay). Results It was revealed that the purified EIEC OPS alone cause cytopathic effect to HeLa cell, and that the OPS caused mucosal hemorrhage, but no fluid accumulation in ileal loop of rabbits. The scanning electron microscope and transmission electron microscope demonstrated the fine structures of cytopathic HeLa cell were damaged. Conclusion Escherichia coli O29 OPS might be one of the factors causing diarrhea and its mechanism was different from endotoxin reaction of LPS. Escherichia coli O29(pathogen) OPS showed a marked serious toxicity as compared with Escherichia coli HB101(nonpathogen) OPS.