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Biomedical subjects

Z X Zheng

Publications and source records attributed to Z X Zheng.

At least 19 recordsLinked to original sources
PubMed2003

A recombinant fusion protein and DNA vaccines against foot-and-mouth disease virus type Asia 1 infection in guinea pigs.

On the basis of amino acid (aa) sequence of the tandem repeat 133-158-20-34-133-158 which consisted of aa 133-158 of VP1 and aa 20-34 of VP4 of Foot-and-mouth disease virus (FMDV) type Asia 1 a recombinant prokaryotic expression vector pAS1-P encoding a fusion protein and eukaryotic expression vectors pAS1-E and pAS1-EdeltaCpG-ODN representing DNA vaccines were constructed. Guinea pigs immunized with these vaccines showed both neutralizing antibody and T cell proliferation responses. FMDV challenge tests for the first time showed that the recombinant fusion protein and pAS1-E and pAS1-EdeltaCpG-ODN vaccines protected 86%, 60% and 43% of guinea pigs from FMDV type Asia1 challenge, respectively. The results also indicated that the immune response of animals treated with the vector pAS1-E containing an oligodeoxynucleotide (ODN), which consisted of immunostimulatory cytosine-phosphate-guanosine (CpG) motifs, was augmented by CpG ODN.

Animals↗
PubMed2002

Immunogenicity of a recombinant fusion protein of tandem repeat epitopes of foot-and-mouth disease virus type Asia 1 for guinea pigs.

In this study, the sequences of capsid protein VPI regions of YNAs1.1 and YNAs1.2 isolates of foot-and-mouth disease virus (FMDV) were analyzed and a peptide containing amino acids (aa) 133-158 of VP1 and aa 20-34 of VP4 of FMDV type Asia I was assumed to contain B and T cell epitopes, because it is hypervariable and includes a cell attachment site RGD located in the G-H loop. The DNA fragments encoding aa 133-158 of VP1 and aa 20-34 of VP4 of FMDV type Asia 1 were chemically synthesized and ligated into a tandem repeat of aa 133-158-20 approximately 34-133-158. In order to enhance its immunogenicity, the tandem repeat was inserted downstream of the beta-galactosidase gene in the expression vector pWR590. This insertion yielded a recombinant expression vector pAS1 encoding the fusion protein. The latter reacted with sera from FMDV type Asia 1-infected animals in vitro and elicited high levels of neutralizing antibodies in guinea pigs. The T cell proliferation in immunized animals increased following stimulation with the fusion protein. It is reported for the first time that a recombinant fusion protein vaccine was produced using B and T cell epitopes of FMDV type Asia 1 and that this fusion protein was immunogenic. The fusion protein reported here can serve as a candidate of fusion epitopes for design of a vaccine against FMDV type Asia 1.

Animals↗
PubMed2001

[Study on the DNA vaccine against foot-and-mouth disease virus using the heavy chain constant region of swine IgG as the carrier for peptide epitopes].

The peptide of amino acids 141-160 of VP1 protein of foot-and-mouth disease virus (FMDV) is a major B cell epitope and the peptide of amino acids 21-40 is an important T cell epitope. In this study, the DNA fragments of 141-160 and 21-40 peptide epitopes of a strain of type O FMDV was chemically synthesized and arranged into a tandem repeat 141-160 (20AA)-21-40 (20AA)-141-160 (20AA). This tandem sequence was fused to the 3' end of the heavy chain constant region gene of swine immunoglobulin G and was then cloned into mammalian expression vector pCDM8 to form a recombinant plasmid pCDM8FZ3. After pCDM8FZ3 was inoculated intramuscularly into guinea pigs, it elicited a neutralizing antibody response and a specific spleen T cell proliferative response, and 66% of the vaccinated animals were protected from viral challenge. Our study indicated that the heavy chain constant region of swine IgG can act as the carrier protein for FMDV peptide epitopes, and pC-DM8FZ3 is a potential DNA vaccine candidate to prevent FMDV infection.

Animals↗
PubMed2000

Plasmids encoding foot-and-mouth disease virus VP1 epitopes elicited immune responses in mice and swine and protected swine against viral infection.

VP1 is a capsid protein of foot-and-mouth disease virus (FMDV) and contains epitopes of the virus. Plasmids encoding two VP1 epitopes (amino acid residues 141-160 and 200-213) and a host-self immunoglobulin molecule were constructed to produce a new type of FMD DNA vaccine. Two plasmids, namely, pCEIM and pCEIS, containing mouse immunoglobulin (IgG) or swine IgG were subjected to immunogenicity testing in mice and swine, respectively. In mice administrated pCEIM in the abdomen using a genegun, both FMDV-specific T-cell proliferation and neutralizing antibodies were detected. In swine immunized with pCEIS at the back of the ear, immune responses were achieved after the second administration. Swine showed a T-cell proliferative response with a stimulation index (SI) of up to 8.1 and a neutralizing antibody response that was able to protect suckling mice from 10(2) LD(50) (lethal dose 50) FMDV challenge. To compare the immunogenicity of the DNA-based vaccine candidate, versus the protein-based vaccine candidates, a second group of swine was immunized with the protein F1-scIgG, which was encoded by the plasmid pCEIS. Injection with F1-scIgG elicited a T-cell proliferative response of SI < 1.7 and a neutralizing antibody response that protected suckling mice from up to 10(5) LD(50) FMDV challenge. In the challenge test, three of three swine immunized with pCEIS were fully protected from FMDV challenge.

Animals↗
PubMed2000

An immunoglobulin G based chimeric protein induced foot-and-mouth disease specific immune response in swine.

Epitopes containing the residues 141aa-160aa and 200aa-213aa from foot-and-mouth disease (FMD) serotype O1K HK type FMDV VP1 were joined to a swine immunoglobulin G single heavy chain constant region (scIgG), creating a novel chimeric protein, named F1-scIgG. In this study, inoculation with F1-scIgG induced both FMD virus-neutralizing antibody response and T cell response in swine. Antisera from these F1-scIgG-inoculated swine protected suckling mice against 1000 lethal dose 50 (1000LD(50)) FMD challenge. F1-scIgG-inoculated swine were also fully protected against 50LD(50) FMD virus challenge. The present study demonstrates the clear potential for viral epitopes linked with self-Ig in novel FMD vaccine design.

Animals↗
PubMed1999

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application.

OBJECTIVES: The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans. BACKGROUND: Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation. METHODS: Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests. RESULTS: The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing. CONCLUSIONS: These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.

Adolescent↗
PubMed1997

[Modulation of T-cell-mediated immune responses by trichosanthin via antigen processing and presentation].

It has been shown in our previous study that the lymphoproliferation to allo- or soluble antigens could be inhibited when T cells were cocultured with antigen presenting cells (APCs) pulsed with Trichosanthin (Tk), a plant protein purified from a Chinese medicinal herb Trichosanthes kirilowii Maximovich. In this paper, data are presented dealing with the mechanism by which the Tk functioned as a down modulator. APCs of human peripheral blood were first treated with one of inhibitors of antigen processing (chloroquine, leupeptin or cycloheximide), followed by pulsed with Tk, and then added into a T cell culture with stimulators PMA and A 23187. The suppression of lymphoproliferation was observed to be obviously diminished or totally disappeared. In contrast, when CyA was used to replace the Tk for pulse-treatment of APCs that had received the same pretreatment with the inhibitors, no significant change was detected for the suppression, suggesting that the Tk might use a different pathway to induce hyporeactivity and that the pathway was concerned in APC's function of antigen presentation. This view obtained support from our immuno-histochemical examination of the Tk-pulsed APCs. By preparing colloidal gold-labelled Tk (Tk-G particle), we were able to show that the Tk-G, when incubated with APCs and T cells at 37 degrees C for two hours and washed, was visualized under the electronic microscope to be bound to APCs', instead of T cells', membrane surface and internalized cells' into endosomes. And then the Tk-G particles were further identified within lysosomes. In this way, the Tk molecules were subjected to be processed as an external antigen and might be presented to T cells to activate certain T subsets that in turn mediated the immunosuppression. This course was capable of, as expected, being interrupted by antigen processing inhibitor, especially by chloroquine.

Antigen Presentation↗
PubMed1994

[Cloning and sequencing of a DNA fragment from Plasmodium falciparum FCC1/HN isolate].

A specific DNA fragment isolated from Plasmodium falciparum FCC1/HN isolate has been cloned in Bam H1 site of pUC18 and first partially sequenced by Sanger's method. The results show: G+C percent of DNA sequence is 26.8%, and the cloned DNA has many restriction sites which are conventional for subcloning. The authors suggest that this clone and sequence may be used as a guide for developing a DNA probe or PCR primers.

Animals↗
PubMed1993

Survey of 160 centenarians in Shanghai.

One hundred and sixty centenarians were discovered and followed up for 7 years (1982-88) in Shanghai. The proportion of centenarians in the population was non-significantly greater in the urban than in the rural area and centenarians were in general increasing in both areas over the years. The factors promoting longevity were good medical care and benevolent attention from family members. Autopsy was performed in eight centenarians revealing the main causes of death as pneumonia and cancer.

Activities of Daily Living↗
PubMed1991

Influence of operation under epidural anesthesia on peripheral t lymphocyte subsets.

This paper reports the variation of peripheral T lymphocyte subsets in patients before and after operation under epidural anesthesia using OKT monoclonal antibodies (McAb). The results show that TH and TS after anesthesia and during surgery were lower than before anesthesia and in normal controls (P less than 0.05). The ratio of TH/TS after anesthesia and during operation were lower than before anesthesia (P less than 0.05), but there was no significant difference with normal controls (P greater than 0.05). Therefore, we consider that the decrease in TH cells was one of the reasons for decrease in patient immune function during anesthesia and surgery. Five to seven days after surgery, patient TH cell levels tended to normalize. This showed that this abnormality was transient and reversible. The results also indicated that emphasising prevention of infection in post-operational case, should be done during the first 5-7 days after surgery.

Adult↗
PubMed1990

[Construction of a cDNA library of Schistosoma japonicum].

The template mRNA was extracted from Schistosoma japonicum. The first strand of cDNA was synthesized by AMV-reverse transcriptase. The second strand cDNA was first digested by RNase H to remove mRNA and was then synthesized by AMV-reverse transcriptase, T4-DNA polymerase. Sizing of cDNA was applied on a NACS column to remove small fragments of less than 1 kb. Homopolymeric tailing of vector (pUC18) was done with dGTP and DNA terminal transferase and tailing of the cDNA with dCTP was carried out under the same conditions. After annealing, the plasmids with cDNA were transformed into E. coli MC1061. The efficiency of cloning was about 10(4)/micrograms mRNA with 30% of the transformants having the inserts of cDNA (Figs. 1-2).

Animals↗
PubMed1990

[Screening of Schistosoma japonicum adult worm genomic DNA library by specific antibody].

S. japonicum adult worm genomic DNA libraries were screened by enzymeimmunoassay. The antigens produced by recombinant lambda gt 11 plaques were transferred to nitrocellulose filters. Clones encoding given antigens were detected with infected rabbit sera (IRS) which were preabsorbed with lysate of induced lambda gt 11 in Y1090 cells. Eight putative positives were picked up from 97 plates in the primary screening and were rescreened a second time, and, 2 of them consistently gave good positive signals in subsequent screenings. One of the phage clones was purified to homogeneity and mixed with Y1089 cells. The expressed products still showed positive when rescreened by ELISA, indicating that the clone encoding S. japonicum antigen could be recognized by IRS. The immunoscreening method described here was able to efficiently isolate single clones encoding S. japonicum antigens. The method has the advantages of screening libraries efficiently, reliably and specifically, and it might open the way to screen genes encoding S. japonicum antigens inducing protective immunity (Fig. 1).

Animals↗
PubMed1989

[Changes of the release of atrial natriuretic factor (ANF) and its gene transcription in morphine tolerance rat atrium].

Specific radioimmunoassay and molecular hybridization technique were used in the present work. Compared with the control rats, we found for the first time a significant decrease of ANF in plasma and a marked increase of ANF in atria in morphine tolerant rats. Simultaneously a raised level of ANF messenger RNA in morphine tolerant rat atria was observed. It is suggested that the biosynthesis and storage of ANF in atria be increased and its release from atria decreased in morphine tolerant rats.

Animals↗