Study on the safety and immunogenicity of enterotoxigenic Escherichia coli recombinant active vaccine / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the safety, immunogenicity on the enterotoxige Escherichia coli (E. coli) recombinant active vaccine FE3 and FE16.</p><p><b>METHODS</b>Toxicity and immunogenicity of the vaccine were determined by experiments on enterotoxigenic E. coli toxicity and immunological experiments on rabbits and mice.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>The enterotoxigenic E. coli recombinant active vaccine showed good safety and immunogenicity, inducing both humoral and mucosal immunity in mice.</p>

Study on molecular epidemiology of Mycobacterium tuberculosis in Chinese army with PCR amplified fingerprinting methods / 中华流行病学杂志

<p><b>OBJECTIVE</b>Typing of Mycobacterium tuberculosis strains and epidemiological studies in the army of southern China to provide scientific basis for prevention of pulmonary tuberculosis.</p><p><b>METHODS</b>A rapid fingerprinting of M. tuberculosis strains method by polymerase chain reaction (PCR) with outward-directed primers that designed to the ends of the insertion sequence IS6110 was developed, and to analyze the relationship between the polymorphism of DNA fingerprinting and epidemiology of M. tuberculosis.</p><p><b>RESULTS</b>One hundred and fifty-four M. tuberculosis detected were classified into eight types according to their characters of PCR amplified fingerprints. The main types were type I (36.4%), type II (31.8%), and type III (21.4%), while other types were less than 4 percentage. In those main type groups, patients aged 20 to 29 and 30 to 39 took up 31.8% and 27.9% respectively. For those main types, the distribution of those types in the first treated patients showed significant difference compared with that in the retreated patients, and the rate of drug-resistance was also statistically different. However, the distribution was not statistically significant to history of BCG vaccination and patients living in urban or rural area. The main drug-resistant strains were only Isoniazid-resistant or Rifampin-resistant strains, while the drug-resistant strains were 44.4%, 29.6% and 14.8% respectively in type I, type II and type III.</p><p><b>CONCLUSION</b>PCR fingerprinting was a rapid, precise, sensitive, specific method to type M. tuberculosis, and could be used to study the epidemiology of tuberculosis; The prevalence of tuberculosis was primarily due to the transmission of type I, type II and type III in the army being studied from Southern China, to suggest that surveillance needs to be strengthened.</p>

Study on DNA fingerprinting of Mycobacterium tuberculosis strains isolated in Southern Chinese army by IS6110-restriction fragment length polymorphism / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the correlation between DNA fingerprinting of Mycobacterium tuberculosis (MTB) stains isolated from the Chinese army in the south and from local residents, and to investigate the molecular epidemiological characteristics of tuberculosis (TB) in the army, for the sake of TB prevention in the army.</p><p><b>METHODS</b>MTB DNA was digested with restriction endonuclease PvuII and electrophoresed in agarose gel, after Southern Blotting, the membrane was hybridized with a 245 bp fragment of IS6110 which labeled [alpha(32)P]-dCTP as probe. Finally, a restriction fragment length polymorphism (RFLP) patterns was shown, and analyzed logestic with epidemiological data from the patients.</p><p><b>RESULTS</b>A total number of 185 TB strains were detected and the IS6110 copy numbers ranged from 1 - 22. No significant difference was found in the IS6110 copy numbers between patients from army and local patients. IS6110 copy numbers of TB strains in army patients were centered in 6 - 20, however, with 7 - 20 copies in local TB patients. The TB strains were dispersed into 8 groups and the majority of TB strains in both army and local patients was centered in groups I, II, III. The distribution of DNA fingerprint for drug resistance TB strains was significantly different from those for sensitive strains. No different distribution of among groups was found regarding BCG history.</p><p><b>CONCLUSIONS</b>The genetics of TB stains were roughly the same between the army patients and local ones, but there was a strong correlation in the gene levels. Data suggested that a close connection should be considered on TB prevention and treatment for TB patients in the army and local residents.</p>

HBV C gene mutation in the transmission from father to infant / 中华儿科杂志

<p><b>OBJECTIVE</b>Hepatitis B virus (HBV) DNA was detected from infants whose mothers were negative for all HBV markers and the fathers were HBV carrier, the homology of HBV sequence of fathers and fetus was high, and HBV mutations concentrated on some points, and the transmission of HBV from father to fetus was also identified in some reports. The present study aimed to study HBV transmission from father to infant.</p><p><b>METHODS</b>The study enrolled 16 pairs of fathers who were HBV carriers and infants whose mothers were negative for HBV markers. The infants had evidences for intrauterine HBV infection. The five HBV serum markers HBsAg, HBeAg, anti-HBe, anti-HBs, and anti-HBc were detected with ELISA. The positive results for HBsAg and/or HBeAg were regarded as markers of HBV infection. Amplification of HBV DNA was done using a nested PCR method. The first amplification was carried out using primer C1 (nt 2394-2370), and primer C3 (nt 1730-1754). The second amplification was carried out using primer C2 (nt 1955-1974) and primer C6 (nt 2348-2330). Both primers were designed to amplify the part of sequence coding for the hepatitis B C antigen. The size of the amplified fragment obtained by the nested PCR was expected to be 394 bp. The PCR products were electrophoresed on 1.5% agarose gels, which were then stained with ethidium bromide and observed with ultraviolet transillumination. When 394 bp specific band was detectable, the sample was designated positive. Then the positive samples were identified by dot blot. The second PCR products were extracted by phenol-chloroform and 70% ethanol precipitation, then resuspended in TE buffer (pH8.0), and used as the template for cloning. The template was connected into pGEM-T vector by ligase. The ligated products were cloned into fresh competent JM109 cells, and incubated for 90 minutes at 37 degrees C on roller drum. Finally several dilutions were plated on plates containing ampicillin, X-Gal and IPTG, and incubated at 37 degrees C overnight. The white colony on plates was used for identification by the nested PCR with the above primers. When the 394 bp band was detectable by electrophoresis of PCR products in 1.5% agarose gels, the colony was designated positive; a positive colony was incubated in LB medium for 8 to 12 hrs, then plasmid was extracted using the Wizard Plus SV Minipreps DNA Purification System Kit (Promega). The purified plasmid was sent to Beijing Saibaisheng Company for sequencing. The homology of HBV C nt 2022-2301 sequence was compared between fathers and infants.</p><p><b>RESULTS</b>The homology of HBV C nt 2022-2301 sequence were 99% - 100% in 16 pairs of fathers and infants. The results were referred to the published sequence of HBV adw/adr clones, and the nucleic acid databases were searched for homology by using BLAST tool on Internet. HBV of the sixteen pairs of father/infant was closely related to the Japan strain (Genebank accession number AF121249), but there were still 17 more mutations at nucleotide positions 2029, 2034, 2044, 2059, 2078, 2095, 2104, 2154, 2161, 2169, 2189, 2201, 2233, 2251, 2284, 2288, 2293. Moreover the mutations at positions 2189, 2288 resulted in the substitution of the encoded amino acid (corresponding to amino acid positions 97 and 130, respectively), the other mutations at the position were nonphenotypic. The mutation of 2189, 2288 nucleotide of HBV C gene caused 97, 130 amino acid substitution for isoleucine to leucine and proline to threonine. The mutation of 2189, 2288 nucleotide of HBV C gene were detected in 6 (37.5%) of 16 pairs of fathers and infants.</p><p><b>CONCLUSION</b>The HBV transmission from father to infants did exist. The main HBV C gene mutation strains also existed in the transmission.</p>