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Li-Xin Wang

Publications and source records attributed to Li-Xin Wang.

34 records · Page 2Linked to original sources
PubMed2004

Synthesis of monodentate chiral spiro phosphonites and the electronic effect of ligand in asymmetric hydrogenation.

New monodentate chiral phosphonites were synthesized from enantiomerically pure 1,1'-spirobiindane-7,7'-diol. The phosphonites 2 were efficient ligands for the Rh-catalyzed asymmetric hydrogenation of alpha- and beta-dehydroamino acid derivatives, providing the amino acids in high enantioselectivities. The study of electronic effect showed that the electron-withdrawing substitutent on the P-phenyl ring of the phosphonite ligand dramatically decreased both the reactivity and enantioselectivity of the ligand.

Journal Article↗
PubMed2004

Contribution of C3d-P28 repeats to enhancement of immune responses against HBV-preS2/S induced by gene immunization.

AIM: To investigate whether P28 derived from C3d can enhance the immune response to HBV-preS2/S induced by directly injection of naked plasmids containing variable repeats of P28 and HBV-preS2/S in fusion form. METHODS: One to four copies of C3d-P28 coding gene, amplified by PCR and modified by restriction endonucleases digestion, were subcloned into a eukaryotic expression vector pVAON33 to construct pVAON33-P28, pVAON33-P28.2, pVAON33-P28.3 and pVAON33-P28.4 (pVAON33-P28.[1-4]). HBV-preS2/S coding sequence was then introduced into the pVAON33-P28.[1-4] and identified by both PCR and DNA sequencing. BALB/c mice were primed by intramuscular gene immunization with 100 microg different recombinant plasmids on day 0 and were boosted by subcutaneous inoculation with HBsAg protein (1 microg) 12 wk post-priming. The levels and avidity of specific IgG in sera collected at the indicated times from each group were determined by ELISA and NaSCN-displacement ELISA, respectively. RESULTS: HBsAg specific antibody response was elicited in groups primed with plasmids pVAON33-S2/S-P28.[1-4] and pVAON33-S2/S. However, the response against HBsAg in the groups primed with pVAON33-S2/S-P28.[1-4] was significantly higher than that in pVAON33-S2/S group, the highest level of the specific antibody response was observed in the groups primed with pVAON33-S2/S-P28.4 (P<0.01). After secondary immunization with specific antigen, the acceleration of antibody levels was significantly higher and faster in the mice primed with DNA expressing preS2/S-P28 fusions than that with DNA expressing preS2/S only (P<0.05). Interestingly, mice primed with DNA expressing preS2/S-P28.4 fusions maintained the highest levels of anti-HBs antibodies in all animals. The avidity assay showed that the avidity index (AI) collected at 18 wk from mice primed with pVAON33-S2/S-P28.3 and pVAON33-S2/S-P28.4 were significantly higher than that from preS2/S-DNA vaccinated mice (P<0.01). CONCLUSION: Different repeats of C3d-P28 can enhance both humoral immune response and avidity maturation of specific antibodies induced by gene immunization, in which four copies of C3d-P28 may be necessary to achieve the most modest antibody response.

Animals↗
PubMed2004

Memory T cells originate from adoptively transferred effectors and reconstituting host cells after sequential lymphodepletion and adoptive immunotherapy.

Adoptive transfer of tumor-specific effector T cells induces regression of advanced tumors and induces a long term memory response; however, the origin of this response has not been clearly defined. In this study Thy1.2+ mice bearing advanced MCA-205 tumors were treated with sublethal total body irradiation, followed by adoptive transfer of congenic Thy1.1+ T cells that had been sensitized to tumor in vivo and then activated ex vivo with anti-CD3, IL-2, and IL-7. Splenocytes were recovered >140 days after the initial therapy, and the L-selectinlow memory cell subset was separated into host Thy1.2+ and transferred Thy1.1+ cells and restimulated ex vivo. Both adoptively transferred Thy1.1+ cells as well as reconstituted host Thy1.2+ cells could specifically eliminate MCA-205 pulmonary metastases. Interestingly, hosts with partial responses followed by tumor recurrence nevertheless harbored memory cells that could be isolated and numerically amplified ex vivo to regenerate potent effector function. Memory cells were recovered after adoptive transfer into lymphodepleted nontumor-bearing hosts, indicating that they were not dependent on continued Ag exposure. These experiments establish that rapid ex vivo expansion of tumor Ag-primed T cells does not abrogate their capacity to become long-lived memory cells. Moreover, immune-mediated tumor regression coincident with lymphoid reconstitution produces another wave of host memory cells. These data suggest an approach to rescuing antitumor immune function even in hosts with long-standing progressive tumor through restorative ex vivo activation.

Animals↗
PubMed2004

[Function of MMP/TIMP on airway remodeling of bronchial asthma and treating effects of Zhichuan capsule].

OBJECTIVE: To explore the mechanism of the bronchial asthma and to study the treating effects of Zhichuan Capsule on the airway remodeling of asthmatic model rats. METHODS: The rat model was established by being sensitized and activated with different density of ovalbumin through prolonged and repeated exposure for 8 weeks. The rats were randomly divided into model group, Zhichuan Capsule treated group, dexameson treated group, and Zhichuan Capsule and dexameson treated group. Another group of normal rats were taken as control. General histological changes were observed by hematoxylin and eosin stained sections. Being standardized by internal perimeter (Pi), the wall thickness (d), internal area (Ai), outer area (Ao) and wall area (WA) of the airway were quantified by computer-assisted image analysis system. The express of MMP-9, TIMP-1, Col I, Col III and ColV in the airway were examined by immunocytochemical methods. During the course of airway remodeling, the dynamic changes of model rats were observed at different time points (2, 4, 6 and 8 weeks after the activating). Statistical comparison was performed by ANOVA followed by Fisher LSD test. RESULTS: (1) Histologic examination showed eosinophil infiltration within the airway walls, epithelial damage, excessive mucus in the lumen and edema in the submucosa of the airways in model rats, and that the collagen deposition increased accompanied by increasing of TIMP-1. In the model rats, MMP-9 increased at the time point of 2 weeks, but it decreased in the late stage (8 weeks after activating) of airway remodeling. And the level of TIMP-1 was far higher than MMP-9 at the time point of 8 weeks. (2) Zhichuan Capsule could down-regulate the level of TIMP-1 in the airway wall, as well as the thickness of airway wall and the collagen deposition. And there were progressing effects when it was used together with dexameson. CONCLUSION: (1) The early increase of MMP-9 is a key point to start remodeling; and the increase of TIMP-1 in the late stage, which inhibits collagenase activity, may play an important role in developing airway fibrosis. Imbalance between MMP-9 and TIMP-1 is a marker of airway remodeling. (2) Zhichuan Capsule can decrease the deposition of collagen and suppress the airway remodeling by inhibiting the TIMP-1 expression.

Analysis of Variance↗
PubMed2004

[Inhibitive effect of previously activated psoralens on K562 cell proliferation].

The objective was to observe the influence of previously activated psoralens on the proliferation of K562 cells, and to provide laboratory data for its clinical usage. K562 cells were treated separately with previously and late activated psoralens, then their trypan blue exclusion inhibited rates (TBIR), cell proliferation inhibited rates (CPIR) and colony forming inhibited rates (CFIR) after culture were compared. The results showed that previously activated psoralens displayed an inhibiting effect on the proliferation of K562 cells with a dose-effect relationship. There was no obvious difference between previously and late activated psoralens on TBIR, CPIR and CFIR. In order to exert the inhibitive effect of previously activated psoralens, the time of ultraviolet ray exposure should be 10 minutes at least, and longer than 12 hours for inhibiting K562. The inhibitive effect of previously activated psoratens decreased as the time interval from activation to its use was prolonged. The inhibiting effect of previously activated psoralens was strongest within 6 hours after activation. In conclusion, both previously and late activated psoralens show inhibiting effects on the proliferation of K562, which may be able to use an antineoplastic drug in clinic.

Cell Proliferation↗
PubMed2003

[Morphological changes following airway remodeling in asthmatic rats].

OBJECTIVE: To explore the establishment of an asthmatic model with airway remodeling in rats by observing the morphological changes of the airway in different stages. METHODS: Animals were divided into two groups: asthmatic group and control group. The subjects were observed at 5 phases: before activation and 2, 4, 6, 8 weeks after activation. General histological changes were observed using hematoxylin and eosin stained sections. Being standardized by internal perimeter (Pi), the wall thickness (d), internal area (Ai), outer area (Ao) and wall area (WA) of the airway were quantified by computer-assisted image analysis system. And the membrane airways were divided into 3 grades (large, media and small airways) to be analyzed. RESULTS: The changes of small airway appeared earlier and greater than the others. The changes of media airway appeared later than the small one. The changes of large airway appeared as later as the 4th week after activation. There were no differences before and after activation in control group (P>0.05). CONCLUSION: (1) Prolonged, repeated and low density Ag activation could establish asthmatic model with airway remodeling. (2) The morphological changes of the airways increased following airway remodeling, and the greatest increase occurred at small airway. (3)The morphological changes in the model rats were similar to that in human beings.

Airway Remodeling↗
PubMed2003

[Protective immunoresponse to CVB3 induced by gene immunization with pcDNA3-VP1].

AIM: To induce Coxsackie virus B type 3 (CVB3)-specific immune response by using a DNA vaccine containing CVB3-VP1 and to observe its protection against CVB3 challenge. METHODS: The gene coding for VP1 was obtained by RT-PCR and then was cloned into plasmid pcDNA3 to construct pcDNA3-VP1. In-vitro expression of VP1 was performed by transfection of pcDNA3-VP1 into Hela cells. Expressed product was detected by ELISA. BALB/c mice were immunized intramuscularly with 50 microg DNA three times, and challenged by 5xLD(50) CVB3 four weeks after the last immunization. RESULTS: pcDNA3-VP1 had been constructed and the expression product was detected in the culture supernatant of Hela cells 24 hours after transfection. CVB3-specific IgM and IgG elicited in the mice immunized with pcDNA3-VP1 were significantly higher than those in the control mice immunized with pcDNA3. Specific proliferation of the splenic lymphocytes and activity of CVB3-specific CTLs from the pcDNA3-VP1 immunized mice were much stronger than those in the controls. pcDNA3-VP1 could protect 33.3% mice from lethal CVB3 challenge, while control mice only survived 6.7 days. Infiltration of inflammatory cells or unusual proliferation of connective tissue, indicating ongoing myocarditis or fibrosis, were not found in pcDNA3-VP1 immunized mice, but did exist in control mice. CONCLUSION: Intramuscular immunization with pcDNA3-VP1 may be a promising approach against CVB3 infection.

Animals↗
PubMed2003

[Enhancement of HBV gene-induced specific cell-mediated immunoresponse by C3d-P28].

AIM: To investigate whether P28 derived from complement C3d can enhance the cell-mediated immunoresponse to HBV-preS2/S induced by direct injection of naked plasmid DNA containing four tandem repeats of C3d-P28 gene and HBV-preS2/S gene existed in fusion form. METHODS: Four copies of gene coding for C3d-P28, amplified by PCR and cut by restriction endonucleases digestion, were subcloned into a eukaryotic expression vector pVAON33 to construct pVAON33-P28.4. HBV-preS2/S gene was then introduced into the pVAON33 and pVAON33-P28.4 respectively to form pVAON33-S2/S and pVAON33-S2/S-P28.4. The recombinant plasmids were identified by PCR and restriction endonucleases digestion as well as DNA sequencing. BALB/c mice were immunized i.m. three times at 3 weeks' intervals with 100 microg of pVAON33-S2/S DNA, pVAON33-S2/S-P28.4 and mock DNA, respectively. Splenocytes from immunized mice were stimulated by HBsAg and then harvested to analyze the specific lymphocytic proliferative response and CTL cytotoxic activity by (3)H-TdR incorporation assay and isotopic release analysis, respectively. RESULTS: Specific lymphocytic proliferation and CTL cytotoxic activity against HBV-preS2/S were observed in mice immunized by both pVAON33-S2/S and pVAON33-S2/S-P28.4 in dose-dependent form. Specific lymphocytic proliferation and CTL response in mice immunized by pVAON33-S2/S-P28.4 were markedly stronger than those in mice immunized by pVAON33-S2/S. CONCLUSION: A C3d-P28 can enhance the cell-mediated immunoresponse induced by HBV-preS2/S gene immunization.

Animals↗
PubMed2002

Adoptive immunotherapy of advanced tumors with CD62 L-selectin(low) tumor-sensitized T lymphocytes following ex vivo hyperexpansion.

Tumor-draining lymph nodes (TDLN) contain sensitized T cells with the phenotype CD62 L-selectin(low) (CD62L(low)) that can be activated ex vivo with anti-CD3 mAb and IL-2 to acquire potent dose-dependent effector function manifested upon adoptive transfer to secondary tumor-bearing hosts. In this study advanced tumor models were used as a stringent comparison of efficacy for the CD62L(low) subset, comprising 5-7% of the TDLN cells, vs the total population of TDLN cells following culture in high dose IL-2 (100 U/ml). During the 9-day activation period the total number of CD8+ T cells increased 1500-fold, with equivalent proliferation in the CD62L(low) vs the total TDLN cell cultures. Adoptive transfer of activated CD62L(low) cells eliminated 14-day pulmonary metastases and cured 10-day s.c. tumors, whereas transfer of maximally tolerated numbers of total TDLN cells was not therapeutic. Despite their propagation in a high concentration of IL-2, the hyperexpanded CD62L(low) subset of TDLN cells functioned in vivo without exogenous IL-2, and CD8+ T cells demonstrated relative helper independence. Moreover, the anti-tumor response was specific for the sensitizing tumor, and long term memory was established. The facile enrichment of tumor-reactive TDLN T cells, based on the CD62L(low) phenotype, circumvents the need for prior knowledge of the relevant tumor Ags. Coupling the isolation of pre-effector T cells with rapid ex vivo expansion to >3 logs could overcome some of the shortcomings of active immunotherapy or in vivo cytokine treatment, where selective robust expansion of effector cells has been difficult to achieve.

Animals↗
PubMedDate not supplied

Efficacy of GM-CSF-producing tumor vaccine after docetaxel chemotherapy in mice bearing established Lewis lung carcinoma.

In this report, we evaluated the efficacy of a GM-CSF-producing tumor vaccine given before and after docetaxel in mice bearing established lung tumors. Mice bearing established 3LL tumors were treated with docetaxel and tumor vaccines transduced with either control or GM-CSF adenoviral vectors. Docetaxel (5-20 mg/kg) treatment alone had only a minimal effect on growth of established 3LL tumors in vivo, although docetaxel was cytotoxic to 3LL cells in vitro. When mice bearing established 3LL tumors were pretreated with docetaxel followed by vaccination with irradiated GM-CSF- transduced 3LL tumor cells, significant tumor regression and prolonged survival were observed compared with chemotherapy alone. Delaying docetaxel treatment until after tumor vaccination abrogated the vaccine's anti-tumor effects. Mice that survived treatment were able to resist a lethal rechallenge of 3LL tumor cells. Memory CTL specific for an epitope (MUT-1) derived from 3LL were detected in surviving mice. Docetaxel induced a mild lymphodepletion in mice, both CD4 and CD8 subsets were reduced in LN and spleens. Interestingly, docetaxel also diminished the number of memory CD8+ T cells (CD122+) and possible CD4+ CD25+ Foxp3+ natural Treg cells. Docetaxel treatment did not affect antigen-driven proliferation of naive T cells but significantly promoted survival of activated T cells. Thus, augmentation of vaccine induced antitumor immunity in docetaxel-treated mice primarily due to the enhanced survival of antigen-experienced T cells.

Adenoviridae↗