The enterobacterial common antigen (ECA) is a polysaccharide composed of polysaccharide repeats that are located in the outer membrane of almost all Enterobacteriaceae bacteria and has diverse biological functions. ECA is synthesized by the synergistic action of multiple genes that are present in clusters on the genome of Enterobacteriaceae bacteria, forming the ECA antigen gene cluster, an important virulence factor that plays a role in host invasion and survival of Enterobacteriaceae in vivo. ECA also plays an important role in the maintenance of the bacterial outer membrane permeability barrier, flagella gene expression, swarming motility, and bile salts resistance. In addition, ECALPS, anchored in the core region of bacterial lipopolysaccharide, is an important surface antigen for bacteria, stimulating high levels of antibody production in the host and could be a target for vaccine research. This review summarizes ECA purification, genes involved in ECA biosynthesis, its immunological characteristics, biological functions and clinical applications.
Antigens, Bacterial/genetics* ; Enterobacteriaceae/genetics* ; Lipopolysaccharides ; Polysaccharides

Animals ; Anthrax ; microbiology ; Antigens, Bacterial ; genetics ; Bacillus anthracis ; genetics ; Bacterial Toxins ; genetics ; Gene Expression Regulation, Bacterial ; Humans ; Receptors, Peptide ; genetics

Antigens, Bacterial ; genetics ; Bacterial Proteins ; Cloning, Molecular ; Interleukin-2 ; genetics ; Mycobacterium bovis ; genetics ; growth & development ; Plasmids ; Recombinant Fusion Proteins ; biosynthesis

The GapC protein of Streptococcus uberis located on the surface of bacteria is a protein with glyceraldehyde-3-phosphate dehydrogenase activity. It participates in cellular processes and exhibits a variety of biological activities. In addition, it has good antigenicity. The aim of this study was to predict the possible B-cell epitopes of the GapC protein and verify the immunogenicity of candidate epitope peptides. The gapC gene of S. uberis isolate RF5-1 was cloned into a recombinant expression plasmid pET-28a-GapC and inducibly expressed. The purified protein was used to immunize experimental rabbits to produce anti-GapC polyclonal antibodies. The three-dimensional structure and three-dimensional location of the GapC B-cell epitopes and the homology comparison of the GapC protein and its B-cell epitopes were carried out using bioinformatics softwares. The results showed that the 44-kDa GapC protein had a good immunological reactivity. Six linear and 3 conformational dominant B-cell epitopes against the GapC protein were selected and synthesized. Three dimensional analysis indicated that the selected peptides have better antigen epitope formation potential. Rabbit anti-GapC polyclonal antibodies were generated after immunized with the purified GapC protein, and the polyclonal antibodies were used to identify the epitope peptide by an indirect ELISA. The ELISA results showed that all of the 9 epitope peptides could react with anti-GapC polyclonal antibodies with varying titers. Among them, the epitope polypeptide ²⁶⁶AANDSYGYTEDPIVSSD²⁸² reacted with the polyclonal antibodies significantly stronger than with other epitope peptides. This study laid an experimental foundation for in-depth understanding of the immunological properties and utilizing effective epitopes of the GapC protein of S. uberis.
Animals ; Antigens, Bacterial/genetics* ; Bacterial Proteins/genetics* ; Epitopes, B-Lymphocyte/genetics* ; Mice ; Mice, Inbred BALB C ; Rabbits ; Streptococcus

OBJECTIVEA multiplex PCR system for screening rare blood group antigens K and Yt(b) was constructed to study the distribution of the two blood groups in a Uygur population in Xinjiang, China.

METHODSSequence-specific primers (SSP) were designed based on single nucleotide polymorphism sites of KEL and ACHE alleles encoding the two blood group antigens. The system was designed for simultaneously detecting the two antigens by optimizing the PCR reaction. Three hundred and sixty-two randomly selected healthy individuals were screened. Products of PCR were further analyzed for heterozygosity.

RESULTSThe system was set up successfully. No KK sample was identified and 9 K+ k+ , 41 Yt (a+ b+ ), 4 Yt (a- b+ ) were found among the 362 samples.

CONCLUSIONThe established PCR-SSP based multiple PCR system is efficient to screen the rare blood group antigens K and Yt(b). The information of rare blood donors obtained from the screening can be used to improve the capability of compatible transfusion.

Antigens, Bacterial ; genetics ; Antigens, Surface ; genetics ; Blood Donors ; Blood Group Antigens ; genetics ; Blood Transfusion ; methods ; China ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Polymorphism, Single Nucleotide

OBJECTIVEA number of putative virulence factors have been postulated to be relevant to the clinical outcome of Helicobacter pylori infection based on strains identified in the western countries. The aim of this study was to investigate the association between genotypes of vacA, cagA and iceA and duodenal ulcer disease in patients from Hong Kong.

METHODSSeventy-two dyspeptic patients with or without duodenal ulcer disease, with proven H.pylori infection, were studied. Gastric biopsy specimens were analyzed by specific polymerase chain reaction and Southern blot to determine the genotypes of these virulence factors.

RESULTSExcept 6 (8.3%) cases with evidence of multiple infections, all of the remaining 66 cases had vacA signal sequence s1 type strains. Twenty-seven (90%) of the 30 cases with duodenal ulcers were infected with cagA-positive strains, compared with 32 (88.9%) of 36 with non-ulcer dyspepsia (P > 0.05). Similarly, vacA middle region sequences were detected with no significant difference in the two groups, 9 (30.0%) versus 13 (36.1%) for m1b and 21 (70.0%) versus 23 (63.9%) for m2 type. IceA1 subtype was detected in the same frequency in 42 (63.6%) of the 66 cases. Neither cagA nor vacA and iceA were associated with duodenal ulcer disease.

CONCLUSIONNo clear differences were found in the distribution of cagA, vacA and iceA genotypes among patients with duodenal ulcer or non-ulcer dyspepsia. The association of these virulence genes and duodenal ulcer disease needs reappraisal, particularly under geographic considerations.

Antigens, Bacterial ; genetics ; Bacterial Proteins ; genetics ; Duodenal Ulcer ; etiology ; Genotype ; Helicobacter pylori ; pathogenicity ; Humans ; Middle Aged ; Virulence

OBJECTIVETo analyze the genetic differences of Orientia tsutsugamushi (Ot) Sta56 gene between Shandong isolates and other strains deposited in GenBank.

METHODSPCR and restriction fragment length polymorphism (RFLP) were used to amplify the complete sequence of Ot-Sta56 gene. RFLP profiles of Ot were predicted by a computer program according to their complete sequences of Ot-Sta56 gene. PCR amplicon from XDM2 strain was sequenced and analyzed by Clustal X (1.8) and PHYLIP software.

RESULTSThe complete sequences (about 1.6 kbp) of Ot-Sta56 gene were amplified from B16 strain (isolated from patients), FXS2 strain (isolated from A. agrarius) and XDM2 strain. Four species of restriction endonucleases (Hha I, Hinf I, Hae III, Pst I) were used to digest the PCR amplicons from the 3 isolates. When comparing with the RFLP profiles of prototype Ot, the RFLP profiles of PCR amplicons from the 3 isolates were similar to those of Japan Kawasaki strain, but were quite different from the international reference strains Gilliam, Karp, Kato. Results from DNA sequence analysis showed that the complete sequence of Ot-Sta56 gene homology to Japan Kawasaki strain of XDM2 strain was 97%, and deduced amino acid sequence was 92%.

CONCLUSIONData from the complete sequence of Sta56 gene indicated that the genotypes of Ot isolates in Shandong province were similar, but with distinction from the Kawasaki strain.

Amplified Fragment Length Polymorphism Analysis ; Antigens, Bacterial ; genetics ; Bacterial Proteins ; genetics ; Bacterial Typing Techniques ; classification ; DNA, Bacterial ; genetics ; Genes, Bacterial ; Membrane Proteins ; genetics ; Orientia tsutsugamushi ; genetics ; isolation & purification ; Polymorphism, Restriction Fragment Length ; Sequence Analysis, DNA

OBJECTIVETo investigate the distribution of babA2 cagA and vacA genotypes of Helicobacter pylori (Hp) in chronic gastritis and peptic ulcer and to discuss the relationship between babA2, cagA and vacA genotypes of Hp and chronic gastritis and peptic ulcer.

METHODSbabA2, cagA genotypes and vacA subtype of 58 Hp strains isolated from patients of Zhejiang province with chronic gastritis or peptic ulcer were tested by polymerase chain reaction.

RESULTSThe positive rates of babA2, cagA, vacAs1a, vacA m1 and vacA m2 of 58 Hp strains were 87.9%, 100%, 93.1%, 1.7% and 65.5%, respectively. There were no significant differences between the positive rates of babA2, vacA s1a and vacA m2 genes of Hp strains isolated from patients with chronic gastritis and peptic ulcer.

CONCLUSIONThe genotypes of Hp isolated from patients of Zhejiang province were predominatly babA2 positive, cagA positive and vacA s1a/m2. The relationships between babA2, cagA and vacA genotypes of Hp and chronic gastritis and peptic ulcer can not be identified.

Adhesins, Bacterial ; Antigens, Bacterial ; Bacterial Proteins ; genetics ; Carrier Proteins ; genetics ; Chronic Disease ; Gastritis ; microbiology ; Genotype ; Helicobacter pylori ; genetics ; Humans ; Peptic Ulcer ; microbiology

This study was conducted to amplify the cfpl0-esat6 fusion gene by SOE and insert into the integrating shuttle plasmid pMV361 to form the recombinant plasmid. Then another recombinant plasmid was constructed by insertinga-A g signal sequence of BCG. The two recombinant plasmids were introduced into BCG and the induced products from recombinant BCG were analyzed. In conclusion,the successful construction of rBCG expressing the fusion protein CFP10-ESAT6 will be the base of the development of novel Mycobacterium tuberclosis vaccines.
Antigens, Bacterial ; biosynthesis ; genetics ; Bacterial Proteins ; biosynthesis ; genetics ; Mycobacterium bovis ; genetics ; metabolism ; Mycobacterium tuberculosis ; genetics ; Plasmids ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Tuberculosis Vaccines ; biosynthesis

OBJECTIVETo determine expression changes of major outer membrane protein(OMP) antigens of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai during infection of human macrophages and its mechanism.

METHODSOmpR encoding genes and OmpR-related histidine kinase (HK) encoding gene of L.interrogans strain Lai and their functional domains were predicted using bioinformatics technique. mRNA level changes of the leptospiral major OMP-encoding genes before and after infection of human THP-1 macrophages were detected by real-time fluorescence quantitative RT-PCR. Effects of the OmpR-encoding genes and HK-encoding gene on the expression of leptospiral OMPs during infection were determined by HK-peptide antiserum block assay and closantel inhibitive assays.

RESULTSThe bioinformatics analysis indicated that LB015 and LB333 were referred to OmpR-encoding genes of the spirochete, while LB014 might act as a OmpR-related HK-encoding gene. After the spirochete infecting THP-1 cells, mRNA levels of leptospiral lipL21, lipL32 and lipL41 genes were rapidly and persistently down-regulated (P <0.01), whereas mRNA levels of leptospiral groEL, mce, loa22 and ligB genes were rapidly but transiently up-regulated (P<0.01). The treatment with closantel and HK-peptide antiserum partly reversed the infection-based down-regulated mRNA levels of lipL21 and lipL48 genes (P <0.01). Moreover, closantel caused a decrease of the infection-based up-regulated mRNA levels of groEL, mce, loa22 and ligB genes (P <0.01).

CONCLUSIONExpression levels of L.interrogans strain Lai major OMP antigens present notable changes during infection of human macrophages. There is a group of OmpR-and HK-encoding genes which may play a major role in down-regulation of expression levels of partial OMP antigens during infection.

Antigens, Bacterial ; genetics ; metabolism ; Bacterial Outer Membrane Proteins ; genetics ; metabolism ; Cell Line ; Chaperonin 60 ; genetics ; metabolism ; Humans ; Leptospira interrogans ; genetics ; immunology ; pathogenicity ; Lipoproteins ; genetics ; metabolism ; Macrophages ; microbiology