Publications by authors named "Xu Zhi-kai"

Introduction: Urolithiasis affects many people throughout their lives. Among the maternal population, although the morbidity of acute urolithiasis in pregnant women is unremarkable, it is the leading cause of hospitalisation during pregnancy. There is no effective clinical diagnostic tool to help doctors diagnose diseases.

View Article and Find Full Text PDF

Dormancy-associated antigens encoded by the dormancy survival regulon (DosR) genes are required for survival of Mycobacterium tuberculosis (Mtb) in macrophages. However, mechanisms underlying survival of Mtb in macrophages remains to be elucidated. A recombinant Mycobacterium smegmatis strain (rMs) expressing a fusion protein of two dormancy‑associated antigens Rv2031c and Rv2626c from Mtb was constructed in the present study.

View Article and Find Full Text PDF

Hantaviruses encompass rodent-borne zoonotic pathogens that cause severe hemorrhagic fever disease with high mortality rates in humans. Detection of infectious virus titer lays a solid foundation for virology and immunology researches. Canonical methods to assess viral titers rely on visible cytopathic effects (CPE), but Hantaan virus (HTNV, the prototype hantavirus) maintains a relatively sluggish life cycle and does not produce CPE in cell culture.

View Article and Find Full Text PDF

A safe and effective Hantaan virus (HTNV) vaccine is highly desirable because HTNV causes an acute and often fatal disease (hemorrhagic fever with renal syndrome, HFRS). Since the immunity of the inactivated vaccine is weak and the safety is poor, HTNV virus-like particles (VLPs) offer an attractive and safe alternative. These particles lack the viral genome but are perceived by the immune system as virus particles.

View Article and Find Full Text PDF

The cytotoxic T lymphocyte (CTL) response plays a key role in controlling viral infection, but only a few epitopes within the HTNV glycoprotein (GP) that are recognized by CTLs have been reported. In this study, we identified one murine HTNV GP-derived H2-K-restricted CTL epitope in C57BL/6 mice, which could be used to design preclinical studies of vaccines for HTNV infection. First, 15 8-mer peptides were selected from the HTNV GP amino acid sequence based on a percentile rank of <=1% by IEDB which is the most comprehensive collection of epitope prediction and analysis tool.

View Article and Find Full Text PDF

Hepatitis C virus (HCV) envelope protein E2 is required for the entry of HCV into cells. Viral envelope proteins interact with cell receptors in a multistep process, which may be a promising target for the development of novel antiviral agents. In this study, a heptapeptide M13 phage-display library was screened for peptides that bind specifically to prokaryotically expressed, purified truncated HCV envelope protein E2.

View Article and Find Full Text PDF

Hantavirus glycoprotein Gc is one of the main components that contribute to the generation of humoral immune responses, while the nucleocapsid protein (NP) is involved in cellular immune responses through the induction of antibody-dependent cytotoxic T cells. In this study, a chimeric gene, GcS0.7, which encodes a fusion protein containing Gc and truncated NP, was constructed as a candidate for Hantaan virus (HTNV) vaccine development.

View Article and Find Full Text PDF

To develop a vaccine against hepatitis C virus (HCV), a multi-epitope peptide was synthesized from nonstructural proteins containing HLA-A2 epitopes inducing mainly responses in natural infection. The engineered vaccine candidate, VAL-44, consists of multiple epitopes from the HCV NS5A, NS4B and core proteins. Immunization with the VAL-44 peptide induced higher CTL responses than those by the smaller VL-20 peptide.

View Article and Find Full Text PDF

Background: Enterovirus 71 (EV71) is a highly infectious agent that plays an etiological role in hand, foot, and mouth disease. It is associated with severe neurological complications and has caused significant mortalities in recent large-scale outbreaks. Currently, no effective vaccine or specific clinical therapy is available against EV71.

View Article and Find Full Text PDF

Aim: To construct and express a trichosanthin (TCS) gene mutant and purify the expressed product in E.coli.

Methods: The potential antigenic determinant was predicted on TCS molecule by computer modeling and induced for site-directed mutation.

View Article and Find Full Text PDF

The mol-ecule of the title compound {systematic name: 17,35-bis-[(2-propyn-1-yl-oxy)meth-yl]-2,5,8,11,14,20,23,26,29,32-deca-oxatricyclo-[31.3.1.

View Article and Find Full Text PDF

Hantavirus glycoproteins (Gn and Gc) are significant components of vaccines for haemorrhagic fever with renal syndrome (HFRS); however, they are not effective due to weak immunogenicity and low levels of production in expression systems. To circumvent this problem, a 0.7-kb fragment of the S segment was fused to Gn, and a hybrid CAG promoter/enhancer in conjunction with (or without) the WPRE (Woodchuck hepatitis virus post-transcriptional regulatory element) was used to improve the expression of fusion protein GnS0.

View Article and Find Full Text PDF

Brucella cell surface protein (BCSP31) is potentially useful for diagnosing brucellosis. We aimed to establish a monoclonal antibody (MAb) against Brucella melitensis BCSP31 and to investigate its distribution in diagnosis. Soluble recombinant BCSP31 was successfully expressed and purified.

View Article and Find Full Text PDF

Aim: To stably express herpes simplex virus type 1 (HSV-1) glycoprotein C (gC) in Chinese hamster ovary cells (CHO-K1).

Methods: The eukaryotic expression vector pCI-mCMV-gC-1-IRES-DHFR-L22R was constructed and transfected into CHO-K1 cells by Lipofectamine 2000. The transfected cells were selected by G418 and methotrexate (MTX).

View Article and Find Full Text PDF

Aim: To construct and express a trichosanthin(TCS)gene mutant and purify the expressed product.

Methods: Predict the potential antigenic determinant on TCS molecule by computer modeling and induce site-directed mutation. Amplify gene mutant TCS(RL28-29CG); by PCR using the genomic DNA of Trichosanthes kirilowii as a template and insert into expression vector pRSET-A, then transform to E.

View Article and Find Full Text PDF

Aim: To express G2 fragment of M segment and 0.7 kb fragment of S segment and several CTL epitopes of S segment in adenovirus expression system and investigate the immunological properties of hantaan virus chimeric gene.

Methods: The recombinant adenovirus was constructed and the recombinant adenovirus was obtained after transfecting HEK293 cells.

View Article and Find Full Text PDF

The N-myc downstream-regulated gene-1 (NDRG1) has recently been proposed as a metastasis suppressor, but its precise role remains unclear. To investigate whether NDRG1 can indeed influence the metastasis progress, expression of endogenous NDRG1 was knocked down in human AGS gastric adenocarcinoma cells using RNA interference. Stable NDRG1 "silenced" transfectants showed similar growth rates as their control counterparts.

View Article and Find Full Text PDF

Aim: Identification of membrane protein molecules Vero cells binding JEV.

Methods: Membrane protein extract was subject to co-immunoprecipitation (Co-IP) with JEV, and identified by mass (MS) spectrometry. The binding between specific extract protein and JEV was measured by MS, flow cytometry (FCM) and immunofluorescence assay (IFA).

View Article and Find Full Text PDF

Aim: To construct a adenovirus vector containing the 0.7 kb fragment of S gene of Hantavirus, CAG promoter, and WPRE (mRNA-stabilizing post-transcriptional regulatory element from the woodchuck hepatitis virus).

Methods: The fragments of CAG and WPRE were synthesized according to GenBank, and inserted into the plasmid pShuttle-S0.

View Article and Find Full Text PDF

Aim: To evaluate immunoprophylaxis of recombinant Mycobacterium vaccae secreted MPT64 of Mycobacterium tuberculosis.

Methods: BALB/c mice were immunized with recombinant Mycobacterium vaccae secreted MPT64 of Mycobacterium tuberculosis. ELISA was used to detect the anti-MPT64 antibody titers and subtype in immunized mice sera.

View Article and Find Full Text PDF

Purpose: Carbapenems are important agents for the therapy of Gram-negative bacillus infections, and the development of their resistance hampers effective therapeutic options. The purpose of this study was to assess the major mechanisms and risk factors leading to carbapenem resistance in clinical Pseudomonas aeruginosa isolates.

Methods: Thirty-four clinical isolates with differing degrees of carbapenem susceptibility were analyzed for carbapenemase, porin, and efflux systems.

View Article and Find Full Text PDF

Developing a new generation of vaccines is important for preventing tuberculosis (TB). DNA vaccine is one promising candidate. In this study we evaluated the immunogenicity and protective efficacy of the DNA vaccine encoding the fusion protein of Mycobacterium tuberculosis heat shock protein 65 (Hsp65) with human interleukin-2 (hIL-2) in BALB/c mice.

View Article and Find Full Text PDF

Objective: To construct PEGylated trichosanthin (TCS) mutein and analyze its bioactivities, immunogenicity, acute toxicity, and pharmacokinetics.

Methods: The potential antigenic determinant site YFF81-83 in the molecule of TCS was selected to undergo site-directed mutagenesis. Thus, a TCS mutein named TCS(YFF81-83ACS) was constructed and expressed in Escherichia coli of the line BL21 (DE3).

View Article and Find Full Text PDF

Aim: To investigate the immunobiology of Rpf domain from Micrococcus luteus.

Methods: BALB/c mice were immunized with Rpf domain three times at 2-week interval. ELISA was used to detect the title of the anti-Rpf domain antibody titer in the immunized mice sera.

View Article and Find Full Text PDF

Hepatitis C virus (HCV) infection is the major etiological agent of chronic hepatitis, which leads to liver cirrhosis and hepatocellular carcinomas. HCV NS3 helicase is a promising target of anti-virus therapy. In this report, we discuss a strategy to generate monoclonal antibodies (MAbs) of the HCV NS3 helicase, and investigate its potential characteristic.

View Article and Find Full Text PDF