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Objective:To establish an in vivo infection model of H5N1 pseudovirus and to detect the neutralizing activity of FHA3 antibody using this model. Methods:Based on the sequence information of hemagglutinin (HA) and neuraminidase (NA) of A/Anhui/1/2005/H5N1 strain, two recombinant plasmids of pcDNA3.1-HA5 and pcDNA3.1-NA1 were constructed. The two plasmids and plasmid pNL4-3.Luc.R-E- were co-transfected into 293T cells to prepare H5N1 pseudovirus supernatant. The morphology of pseudovirus particles in the supernatant was observed by electron microscopy. MDCK cells were infected with the pseudovirus supernatant and the virus titer was detected. BALB/c mice were injected with the pseudovirus supernatant by intraperitoneal injection and subjected to bioluminescence imaging at 2, 5, 8, and 12 d after infection to detect the pseudovirus infection in vivo. The functional activity of FHA3 antibody in vivo was evaluated using the established mouse infection model. Results:The recombinant plasmids pcDNA3.1-HA5 and pcDNA3.1-NA1 were correctly constructed and could be used to prepare pseudovirus supernatants of high titer by co-transfecting 293T cells with the plasmid pNL4-3.Luc.R-E-. The virus particles were round under electron microscope. H5N1 pseudovirus-infected mice exhibits strong fluorescence signals, which were attenuated by FHA3 treatment before challenge.Conclusions:The in vivo infection model of H5N1 pseudovirus was successfully constructed and FHA3 antibody was proved to be protective against the pseudovirus infection.
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Objective:To prepare and identify a functional antibody FNA1 targeting the neuraminidase (NA) of influenza A virus N1 subtype.Methods:According to single-chain antibody fragment (scFv) sequence, the heavy chain and light chain variable region sequences of FNA1 were synthesized, and the recombinant expression plasmid pFRT-IgG1κ-FNA1 was constructed by linking the expression vector pFRT-IgG1κ. The FNA1 antibody was expressed in ExpiCHO cells and purified using affinity purification technique. The binding ability of FNA1 to the target proteins, influenza A virus N1 subtype NA antigens, was detected by ELISA. Flow cytometry was performed to analyze the binding ability of FNA1 to the NA antigens expressed on the surface of cell membrane. The in vitro activity of FNA1 against NA was evaluated by infecting 293T cells with pseudovirus. Results:Protein electrophoresis showed that FNA1 with high purity was obtained. FNA1 specifically recognized and bound to N1 subtype NA antigens in a concentration-dependent manner. FNA1 could effectively block NA activity by binding to N1 subtype NA protein expressed on the surface of cell membrane, thus inhibiting the release of packaged pseudovirus from cell surface and further inhibiting target cell infection.Conclusions:An antibody FNA1 targeting influenza A virus N1 subtype NA with in vitro functional activity was obtained.
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Objective:To prepare and identify a broad-spectrum antibody FHA3 targeting influenza A virus hemagglutinin (HA).Methods:According to the single-chain antibody fragment (scFv) sequence, the heavy chain (VH) and light chain (VL) variable regions of FHA3 were amplified by PCR and a recombinant plasmid pFRT-IgG1κ-FHA3 was constructed by linking the expression vector pFRT-IgG1κ. FHA3 was expressed in the ExpiCHO system and purified by affinity purification. The binding activity of FHA3 to influenza A virus HA was detected by ELISA. The neutralizing activity of FHA3 was detected in vitro by infecting host cells with pseudovirus. Results:SDS-PAGE showed that high-purity FHA3 was obtained. FHA3 could bind to H1N1 HA, H2N2 HA, H3N2 HA, H5N1 HA, H7N9 HA and H9N2 HA in a concentration-dependent manner. FHA3 had good neutralizing activity in vitro that was it could effectively block the invasion of H5N1 and H7N9 pseudoviruses into target cells at a low concentration of 5 μg/ml and H1N1 pseudovirus at 0.012 5 μg/ml. Conclusions:A broad spectrum antibody targeting HA protein of influenza A virus with neutralizing activity in vitro was obtained.
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5-Fluorouracil(5-FU)has been widely used to treat gastrointestinal,head,neck,chest and ovarian malignant tu-mors since 1957. As an analogue of pyrimidine,5-FU plays anti-cancer roles by inhibiting thymioylate synthase and integrating its me-tabolites into DNA and RNA. Although 5-FU is one of the first-line therapeutic compounds for gastrointestinal malignant tumor as a sin-gle drug or in combination with other drugs,its effectiveness is hindered by its low efficiency,which may be due to chemotherapy re-sistance. 5-FU chemotherapy resistance may stem from enzyme abnormality,genetic abnormality and tumor microenvironment. In this paper,we make a review about 5-FU actions and the mechanisms underlying chemotherapy resistance.
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Colorectal cancer(CRC)ranks the third in incidence and mortality rate among human tumors. Tumor relapse,me?tastasis and drug resistance remain the main obstacle to the success of CRC treatments. Compared to traditional chemotherapy ,target therapy seems to treat tumors in more precise and rational fashion with good response and often less toxic side-effect. Although target agents provide hope for more effective therapy,recent clinical studies have shown only modest benefit from target therapy similar to tra?ditional chemotherapy. Primary and secondary resistance to target agents is still observed and contributes to CRC treatment failure. The review summarizes research progress in the mechanism of drug resistance to target therapy in CRC treatment.
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Objective To evaluate the role of recombinant human soluble Tim-3 (hTim-3-Fc) in regulating immune response.Methods Soluble hTim-3 was incubated with human macrophage cell line U 937, human T cell line Jurkat and normal human PBMC before cytokines secreted by or expressed in different immune cells were analyzed using ELISA , RT-PCR and Western-blotting, respectively.Results Soluble hTim-3 significantly promoted the activation of different immune cells.Our data showed that IL-8 secretion by U937 cells, IL-2 secretion by Jurkat cells , IL-2 and IFN-γsecretion by human PBMCs were all significantly increased .In addition , soluble hTim-3 significantly increased the IFN-α2 and IFN-β1 mRNA expression in U937, Jurkat and PBMCs and increased the phosphorylation of stat-1 in Jurkat and U937 cells.Conclusion Recombinant soluble hTim-3 can significantly promote the activation of immune cells in vitro, which shows its therapeutic potential .
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Objective To ascertain whether estrogen could induce B cell to produce interleukin(IL)-10. Methods C57BL/6 splenic B cells were purified by magnetic activated cell sorting(MACS)method,followed by estrogen treatment for 3 days. The secretion of IL-10 from cultured cell supernatant was tested by ELISA technique. The abundance of mRNA for IL-10、PD-L1 and RBM47 in B cells with estrogen treatment was tested by real-time PCR method. The intracellular IL-10 expression and the surface PD-L1 expression of treated B cells were tested by fluorescence activated cell sorting(FACS)method. And the expression of RBM47 in B cells by estrogen treatment was tested using Western blotting method. Results Estrogen could induce B cell to produce IL-10 in a dose-dependent manner. Estrogen treatment could increase the percentage of IL-10+B cells,the abundance of mRNA for IL-10,PD-L1 and RBM47 in B cells,as well as the expression of PD-L1 on B cell surface. Furthermore,our experimental result indicated the upreg?ulation of RBM47 expression in B cells by estrogen treatment. Conclusion Estrogen treatment in vitro can induce the upregulation of IL-10+regulatory B cells(Breg). Upregulation of RBM47 in the treated B cells might participate in this process by stabilizing IL-10 mRNA.
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Objective To examine whether Tim-3 plays a protective role in paraquat poisoning induced excessive immune response and tissue damage based on the critical roles of Tim-3 controlling inflammatory response.Methods A paraquat poisoning model was established in wild type and in Tim-3 transgenic C57BL/6 mice by intraperitoneal injection of paraquat (40 mg/kg) .In addition, C57BL/6 mice with paraquat poisoning were injected with Tim-3 soluble protein( sTim-3) or control protein to see the effect of Tim-3 blocking on the progression of paraquat poisoning.Samples were collected at 6 and 24 h after paraquat injection respectively and were examined for tissue damage, cytokine expression and paraquat metabolism.Results After paraquat poisoning, there was significantly attenuated tissue damage in the lungs and kidneys and decreased TNF-α,IL-6 and IL-1 beta expression in the PBMCs or in the serum from Tim-3 transgenic mice compared to wild type mice.The serum concentration of paraquat in Tim-3 transgenic mice was also significantly decreased.However, in sTim-3 treated paraquat poisoning mice, there was significantly increased cytokine expression and tissue damage compared to control protein treated mice.The in vitro data showed that Tim-3 signaling negatively regulated macrophages mediated inflammatory response.Conclusion Tim-3 plays a critical role in maintaining the homeostasis after paraquat poisoning. Further investigation on the regulatory roles of Tim-3 in inflammation will shed new light on the pathogenesis of paraquat poisoning and provide new therapeutic strategies.
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OBJECTIVE To investigate the effect of bevacizumab ,an anti-human vascular endothelial growth factor monoclonal antibody,on pulmonary dissemination of colorectal cancer. METHODS A metastatic colorectal cancer mouse model was established. Mice were randomly divided into two groups(n=8). The mice in experimental group were administered ip with bevacizumab at the dosage of 5 mg · kg-1,and those in control group were given isotype IgG at the same dosage. The antibodies were administered on 2 d before initiation of model establishment and 2 d after that,then once every 5 d for 4 weeks,for a total of 7 times. Liver and lung metastases were determined by histopathological examination. The chemokine receptor C-X-C receptor 4(CXCR4)and its ligand C-X-C ligand 12(CXCL12)mRNA expression in the lung were detected by quantitative RT-PCR. Human colon cancer cells HCT116 were treated with bevacizumab(5 mg·L-1)for 24 h. The expression levels of vascular endothelial growth factor receptor 1(VEGFR1)and CXCR4/7 protein as well as CXCR3/4/7 mRNA were examined by Western blotting and quantitative RT-PCR respectively. RESULTS The number of mice(2/8) with liver metastases was reduced,while the number of mice(8/8) with lung metastases increased in experimental group compared with isotype IgG-treated group(6/8 and 2/8 respectively,P<0.05). The mRNA expression level of CXCR4 and CXCL12 in lung tissue was significantly up-regulated in bevacizumab-treated group com?pared with control group(P<0.05). The mRNA and protein expression level of CXCR4 and CXCR7 was dramatically increased in HCT116 cells treated with bevacizumab(P<0.05). CONCLUSION Bevacizumab can potentially promote lung metastases of colorectal cancer,which may be related to up-regulation of CXCR4 and CXCL12 expression.
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Objective To develop a human Tim-3 specific monoclonal antibody and evaluate its biological activity and possible use in clinical diseases associated with dysregulated Tim-3 expression .Methods The BALB/c mice were immu-nized by conventional method, and positive clones were used to develop anti-human Tim-3 antibody, the binding and neutralization activities of which in vitro and in vivo were investigated.Results ①A monoclonal antibody (clone L3D) which could specifically bind to human Tim-3 protein in ELISA assay was obtained and the subtype of the monoclonal antibody was IgG2a .②Flow cytometry indicated that the monoclonal antibody could bind to Tim-3 expressed in human U937 cells.This antibody also showed a cross activity to mice′Tim-3.③The monoclonal antibody inhibited the apoptosis of THP1 cells induced by Gal-9, the ligand of Tim-3.④Injection of Tim-3 antibody exacerbated sepsis in mice as marked by the decreased survival rate and increased expression of pro-inflammatory cytokines .Conclusion An anti-human Tim-3 monoclonal antibody is successfully obtained.The excellent binding and neutralization activities of this antibody enable it to be widely used in clinical diseases associated with deregulated Tim-3 expression .
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Complement system is an important component of innate immunity and has been recognized as an effective means to inhibit tumor. However,in last decades,accumulating studies showed unexpected results that the complement components and their activation products could promote development of malignancies by secreting growth factors,activating signal pathway and promoting tumor angiogenesis. Herein,the relationship between the complement system and tumor is reviewed.