Biomedical subjects

Zhao-shan Zhang

Publications and source records attributed to Zhao-shan Zhang.

4 recordsLinked to original sources

PubMed2005

[Progress on the vaccine for anthrax].

Bacillus anthracis is the causative organism of the potentially fatal disease anthrax, and the used vaccines have some disadvantages. There are new developments appeared for the Bacillus anthracis in recent years, such as anti-PA antibody kills the spore of Bacillus anthracis, mucosal immunization induces immune responses in both systemic and secretory immune compartments, Poly (gamma-D-PGA) protein induce IgG antibodies to the vegetative bacteria, new pathogens were found by genomic analysis. The DNA vaccine and live vector vaccine will be the next generation vaccines for anthrax. It will have a shorter immunization schedule and will be greater protective efficacy than before.

Anthrax↗

PubMed2005

[Study on the safety and immunogenicity of enterotoxigenic Escherichia coli recombinant active vaccine].

OBJECTIVE: To study the safety, immunogenicity on the enterotoxige Escherichia coli (E. coli) recombinant active vaccine FE3 and FE16. METHODS: Toxicity and immunogenicity of the vaccine were determined by experiments on enterotoxigenic E. coli toxicity and immunological experiments on rabbits and mice. RESULTS: The results of an toxicological experiments were negative. The agglutination titer of antibodies against the S. flexneri 2a and enterotoxigenic E. coli plamid antigen were all higher than 1:640 and 1:1280 in the sera of rabbits. IgG in the serum went up remarkably, while sIgA against CFA/I was also decteted in the dejecta of mice immunized with active bacteria either orogastrically or intranasally. Simultaneously, sIgA was not detected in the dejecta of mice immunized with inactive bacteria either orogastrically or intranasally. CONCLUSION: The enterotoxigenic E. coli recombinant active vaccine showed good safety and immunogenicity, inducing both humoral and mucosal immunity in mice.

Administration, Intranasal↗

PubMed2003

[Cloning and immunogenicity of conservative region of adhesin gene of Helicobacter pylori].

OBJECTIVE: To construct a candidate strain of Helicobacter pylori (Hp) that expresses the proteins of the conservative region of 4 adhesins (BabA2, AlpA, AlpB, and HopZ) and study its immunogenicity. METHODS: The DNA of Hp was extracted. Primers were designed according to the C-terminal structural gene sequence (called CB) of AlpA. The CB gene was amplified by PCR and inserted into the prokaryotic expression vector pET-22b (+) and expressed in BL21 (DE3) strain of Escherichia coli. The product of expression, CB, was purified by affinity chromatography and identified by Western blot analysis. ELISA assay was used to measure the CB-specific antibody in the specimens of serum of 55 Hp infected patients. Rapid urease test (RUT) was used on biopsy specimens collected by gastroscopy as parallel control. RESULTS: A recombinant plasmid pET-22b (+)/CB was constructed with the conservative region of the 4 adhesins. DNA sequencing showed one open reading frame of 588 bp encoding a polypeptide of 195 amino acids. The recombinant CB (rCB) protein, with a molecular weight of 22.5KD, amounted to 29% of the total bacterial protein. The purity of purified rCB was 96%. Western blot analysis showed that the rCB protein could be specifically recognized by the serum from Hp infected patients. The kappa coefficient was 0.76 for evaluation by ELISA and RUT results. CONCLUSION: CB has the potential to be used as a vaccine against Hp infection.

Adhesins, Bacterial↗

PubMed2003

[Construction of the non-resistant attenuated Salmonella typhimurium strain expressing Helicobacter pylori catalase].

OBJECTIVE: To construct a non-resistant attenuated Salmonella typhimurium (S.typhimurium) strain capable of expressing Helicobacter pylori (Hp) catalase. METHODS: After PCR amplification, the gene fragment encoding Hp catalase was inserted into the expression vector pYA248 containing asd gene, and the recombinant vector was then introduced into the host S.typhimurium strain X4072 depleted of genes encoding adenylate cyclase (delta cya), cyclic adenosine monophosphate receptor protein (delta crp) and aspartate-beta-semialdehyde dehydrogenase (delta asd). Bridged enzyme-linked immunosorbent assay (ELISA) was employed to measure the antigenicity of the catalase expressed in the sonicate and culture supernatant. According to Meacock's method and with the assistance of the growth curve, the stability of the recombinant strain was evaluated. A half lethal oral dose test was conducted to evaluate the safety of recombinant strain. RESULTS: S.typhimurium X4072 (pYA248-CAT) with expected capacity was successfully constructed, and bridged ELISA demonstrated higher catalase levels in the culture supernatant than in the sonicate of the recombinant strain X4072 (pYA248-CAT). After the strain was passaged for 100 generations without selection pressure, all the randomly selected colony of the recombinant strain grew well with positive catalase antigenicity as identified by ELISA. The growth curve of the recombinant strain showed comparable growth status of the 2 strains X4072 (pYA248) and X4072 (pYA248-CAT). The survival rate of C57BL/6 mice was 100% 30 d after oral administration of 1.0x10(10) cfu X4072 (pYA248-CAT). CONCLUSION: Non-resistant S. typhimurium vaccine X4072 (pYA248- CAT) is constructed successfully, which is stable in vitro and safe as confirmed by animal experiment. This vaccine provides a new candidate for viable oral vaccine against Hp infection.

Administration, Oral↗