OBJECTIVETo recombine OspC gene from Borrelia burgdorferi PD91 of China and expressed it in E. coli for early diagnosis of Lyme disease.

METHODSThe OspC gene was amplified from the genome of Borrelia burgdorferi PD91 strain by polymerase chain reaction and recombined with plasmid PET-11D. The recombinant plasmid PET-11D-OspC was identified with PCR, restriction endonuclease analysis and sequencing. The antigenicity was verified with Western Blot.

RESULTSOspC gene was cloned correctly into vector PET-11D. The resultant sequence was definitely different from the published sequence. The recombinant OspC seemed to have had strong antigenicity.

CONCLUSIONThe findings laid basis for the studies on early diagnosis of Lyme disease.

Antigens, Bacterial ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; Blotting, Western ; Borrelia burgdorferi Group ; immunology ; Escherichia coli ; genetics ; Humans ; Lyme Disease ; diagnosis ; Polymerase Chain Reaction ; Recombinant Proteins ; analysis ; immunology

We previously induced protective immune response by oral immunization with yeast expressing the ApxIIA antigen. The ApxI antigen is also an important factor in the protection against Actinobacillus pleuropneumoniae serotype 5 infection; therefore, the protective immunity in mice following oral immunization with Saccharomyces cerevisiae expressing either ApxIA (group C) or ApxIIA (group D) alone or both (group E) was compared with that in two control groups (group A and B). The immunogenicity of the rApxIA antigen derived from the yeast was confirmed by a high survival rate and an ApxIA-specific IgG antibody response (p < 0.01). The highest systemic (IgG) and local (IgA) humoral immune responses to ApxIA and ApxIIA were detected in group E after the third immunization (p < 0.05). The levels of IL-1beta and IL-6 after challenge with an A. pleuropneumoniae field isolate did not change significantly in the vaccinated groups. The level of TNF-alpha increased in a time-dependent manner in group E but was not significantly different after the challenge. After the challenge, the mice in group E had a significantly lower infectious burden and a higher level of protection than the mice in the other groups (p < 0.05). The survival rate in each group was closely correlated to the immune response and histopathological observations in the lung following the challenge. These results suggested that immunity to the ApxIA antigen is required for optimal protection.
Actinobacillus Infections/prevention & control ; Actinobacillus pleuropneumoniae/genetics/*immunology ; Animals ; Antibodies, Bacterial/blood ; Bacterial Proteins/analysis/*immunology ; Cytokines/analysis/blood ; Disease Models, Animal ; Female ; Hemolysin Proteins/analysis/*immunology ; Immunoglobulin A/blood/immunology ; Intestines/immunology ; Lung/cytology/immunology ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins/*immunology ; Saccharomyces cerevisiae/*genetics/immunology ; Survival Analysis ; Time Factors ; Vaccination ; Vaccines, Synthetic/administration & dosage/*immunology

BACKGROUND: Enzyme immunoassay (EIA) capable of detecting both toxin A and toxin B is strongly recommended for the diagnosis of Clostridium difficile associated disease. Therefore, we evaluated two different EIAs for the detection of C. difficile toxin A/B. METHODS: For a total of 228 stool specimens we performed bacteriologic cultures for C. difficile and examined for toxin A and toxin B using enzyme linked fluorescent immunoassay (ELFA; VIDAS CDAB, Bio-Merieux sa, France) and ELISA (C.DIFFICILE TOX A/B II, TECHLAB, USA). We also performed PCR assays for toxin A and B genes in 117 C. difficile isolates that grew from the stool cultures and compared the results with those obtained with the two different EIAs. RESULTS: The concordance rate between ELFA and ELISA was 85.5% (195/228). Using the culture and PCR results as the standard, the sensitivity/specificity of the ELFA and ELISA were 65.0%/72.1% and 71.8%/70.3%, and for positive/negative predictive values were 78.4%/69.6% and 71.8%/70.3%, respectively (P value >0.05). No differences were observed between the results of ELFA and ELISA with toxin A- toxin B+ strains of C. difficile. CONCLUSIONS: The sensitivity of the ELISA was slightly higher than that of ELFA for toxin A and toxin B, but the specificity and positive predictive value of the ELFA were rather higher than those of the ELISA, although no statistical differences were observed. A bacteriologic culture and PCR assay for toxin genes are recommended in case the both EIAs are negative.
Bacterial Proteins/*analysis/genetics/immunology ; Bacterial Toxins/*analysis/genetics/immunology ; Clostridium difficile/genetics/isolation & purification/*metabolism ; Enterotoxins/*analysis/genetics/immunology ; Enzyme-Linked Immunosorbent Assay/*methods ; Feces/microbiology ; Fluorescent Dyes/chemistry ; Humans ; Reagent Kits, Diagnostic

OBJECTIVETo reconstruct the nucleotide sequence of Leptospira interrogans lipL21 gene for increasing the output of prokaryotic expression and to understand the changes on immunogenicity of the expression products before and after reconstruction, and to determine the position of envelope lipoprotein LipL21 on the surface of leptospiral body.

METHODSAccording to the preferred codons of E.coli, the nucleotide sequence of lipL21 gene was designed and synthesized, and then its prokaryotic expression system was constructed. By using SDS-PAGE plus BioRad agarose image analysor, the expression level changes of lipL21 genes before and after reconstruction were measured. A Western blot assay using rabbit anti-TR/Patoc I serum as the first antibody was performed to identify the immunoreactivity of the two target recombinant proteins rLipL21s before and after reconstruction. The changes of cross agglutination titers of antisera against two rLipL21s before and after reconstruction to the different leptospiral serogroups were demonstrated using microscope agglutination test (MAT). Immuno-electronmicroscopy was applied to confirm the location of LipL21s.

RESULTThe expression outputs of original and reconstructed lipL21 genes were 8.5 % and 46.5 % of the total bacterial proteins, respectively. Both the two rLipL21s could take place immune conjugation reaction with TR/Patoc I antiserum. After immunization with each of the two rLipL21s in rabbits, the animals could produce specific antibody. Similar MAT titers with 1:80 - 1:320 of the two antisera against rLipL21s were present. LipL21 was confirmed to locate on the surface of leptospiral envelope.

CONCLUSIONLipL21 is a superficial antigen of Leptospira interrogans. The expression output of the reconstructed lipL21 gene is remarkably increased. The expression rLipL21 maintains fine antigenicity and immunoreactivity and its antibody still shows an extensive cross immunoagglutination activity. The high expression of the reconstructed lipL21 gene will offer a favorable condition to use its product for further developing a novel universal vaccine as well as detection kit of leptospirosis.

Amino Acid Sequence ; Animals ; Antigens, Bacterial ; genetics ; immunology ; metabolism ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; metabolism ; Bacterial Vaccines ; immunology ; Base Sequence ; Blotting, Western ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Immune Sera ; immunology ; Leptospira interrogans ; genetics ; immunology ; ultrastructure ; Lipoproteins ; genetics ; immunology ; metabolism ; Microscopy, Immunoelectron ; Molecular Sequence Data ; Rabbits ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism ; Sequence Analysis, DNA ; Vaccines, DNA ; immunology

Heat shock protein 65 (HSP65) is one of the most important protective immunogens against the tuberculosis infection. The signal sequence of antigen 85B and the whole HSP65 DNA sequence of human Mycobacterium tuberculosis (M. tuberculosis) were amplified from BCG genome and plasmid pCMV-MTHSP65 respectively by polymerase chain reactions (PCR). These two sequences were cloned into the plasmid pBCG-2100 under the control of the promoter of heat shock protein 70 (HSP70) from human M. tuberculosis, yielding the prokaryotic shuttle expression plasmid pBCG-SP-HSP65. Results of restriction endonuclease analysis, PCR detection and DNA sequencing analysis showed that the two cloned DNA sequences were consistent with those previously reported, and the direction of their inserting into the recombinant was correct and the reading frame had been maintained. The recombinants were electroporated into BCG to construct the recombinant BCG vaccine and induced by heating. The induced expression detected by SDS-PAGE showed that the content of 65 kD protein expressed in recombinant BCG was 35.69% in total bacterial protein and 74.09% in the cell lysate supernatants, suggesting that the recombinant HSP65 gene could express in BCG with high efficiency and the expressed proteins were mainly soluble. Western-blot showed that the secretive recombinant proteins could specifically combine with antibody against M. tuberculosis HSP65, indicating that the recombinant proteins possess the biological activity of HSP65.
BCG Vaccine ; biosynthesis ; immunology ; Bacterial Proteins ; biosynthesis ; immunology ; Chaperonin 60 ; Chaperonins ; biosynthesis ; immunology ; Cloning, Molecular ; Escherichia coli ; metabolism ; Genetic Vectors ; Humans ; Mycobacterium tuberculosis ; genetics ; immunology ; Plasmids ; genetics ; Sequence Analysis, DNA ; Vaccines, Synthetic ; biosynthesis ; immunology

Pertussis is a representative vaccine-preventable disease. However, there have been recent outbreaks in countries where even higher vaccination against the disease. One reason is the emergence of antigenic variants, which are different to vaccine type. In Korea, reported cases have rapidly increased since 2009. Therefore, we analyzed genotype of strains isolated in 2011-2012 by multilocus sequence typing method. As expected, the genotype profiles of tested genes dramatically changed. The major sequence type changed from ST1 to ST2, and new sequence type (ST8) appeared. In the minimum spanning tree, recent isolates belonging to the ACC-I-ST3 subgroup were detected that were composed of ST2, ST3, and ST6. In particular, the ST2 frequency increased to 81%. The novel ST8 was linked to the increased frequency of ST2. In addition, toxic strains carrying the ptxP3 promoter type were confirmed. This ptxP3 type emerged from 2009 and its frequency had increased to 100% in 2012. Based on these results, it can be inferred that the genotypic changes in the currently circulating strains are strongly associated with the recent increasing of pertussis in Korea. Therefore, the surveillance system should be strengthened, and genetic characterization of the isolates should be expanded to the whole genome sequence level.
*Antigenic Variation ; Antigens/*genetics/immunology/metabolism ; Bacterial Proteins/genetics/metabolism ; Bordetella pertussis/*genetics/isolation & purification/*metabolism ; Genes, Bacterial ; Genotype ; Humans ; Pertussis Toxin/genetics/metabolism ; Promoter Regions, Genetic ; Republic of Korea ; Sequence Analysis, DNA ; Whooping Cough/immunology/*microbiology/pathology

Oral vaccination may be the most efficient way of inducing an immune response at the remote mucosal site through the common mucosal immune network. Antigenspecific secretory IgA (sIgA) is the major immunoglobulin type generally detected in the secretions of experimental animals following an effective oral immunization. Actinobacillus pleuropneumoniae causing disease in the lung of pig initially interacts, colonizes, and infects the host tissues at the mucosal surface of the respiratory tract. Also, importantly for A. pleuropneumoniae protection, the quantity of sIgA in the lung had merits associated with the mucosal immunity. However, there is no simple method to monitor the level of sIgA as an indicator for the induction of local immune responses by an oral vaccination in the target tissue. Therefore, the relationship between sIgA and IgG was analyzed to evaluate the induction of local immune responses by an oral immunization with Saccharomyces cerevisiae expressing the apxIA and apxIIA genes of A. pleuropneumoniae in this study. The correlation coefficient of determination (r2 x 100) for paired samples in both vaccinated and control groups showed a significant positive-relationship between IgG in sera and sIgA in the lung or intestine. These results indicated that IgG antibody titers in sera could be useful to indirectly predict local immune response, and sIgA, in the lung or intestine to evaluate the efficacy of an oral vaccination.
Actinobacillus pleuropneumoniae ; Administration, Oral ; Animals ; Antigens, Fungal/*immunology ; Bacterial Proteins/genetics/immunology ; Bacterial Vaccines/*immunology ; Disease Models, Animal ; Female ; Hemolysin Proteins ; Immunity, Mucosal/*immunology ; Immunoglobulin A, Secretory/*analysis ; Immunoglobulin G/*blood ; Intestine, Small/immunology ; Lung/immunology ; Mice ; Mice, Inbred BALB C ; Saccharomyces cerevisiae/*immunology

OBJECTIVELcrV is an important component for the development of a subunit vaccine against plague. To reduce immunosuppressive activity of LcrV, a recombinant LcrV variant lacking amino acids 271 to 326 (rV270) was prepared by different methods in this study.

METHODSA new strategy that produced non-tagged or authentic rV270 protein was designed by insertion of rV270-thrombin-hexahistidine fusion gene into the vector pET24a, or by insertion of hexahistidine-enterokinase-rV270 or hexahistitine-factor Xa-rV270 fusion gene into the vector pET32a. After Co(2+) affinity chromatography, a purification strategy was developed by cleavage of His tag on column, following Sephacryl S-200HR column filtration chromatography.

RESULTSRemoval of His tag by thrombin, enterokinase and factor Xa displayed a yield of 99.5%, 32.4% and 15.3%, respectively. Following Sephacryl S-200HR column filtration chromatography, above 97% purity of rV270 protein was obtained. Purified rV270 that was adsorbed to 25% (v/v) Al(OH)₃ adjuvant in phosphate-buffered saline (PBS) induced very high titers of antibody to rV270 in BALB/c mice and protected them (100% survival) against subcutaneous challenge with 10⁶ CFU of Y. pestis virulent strain 141.

CONCLUSIONThe completely authentic rV270 protein can be prepared by using enterokinase or factor Xa, but they exhibited extremely low cleavage activity to the corresponding recognition site. Thrombin cleavage is an efficient strategy to prepare non-tagged rV270 protein and can be easily operated in a large scale due to its relatively low cost and high cleavage efficacy. The recombinant rV270 can be used as a key component to develop a subunit vaccine of plague.

Amino Acid Sequence ; Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; genetics ; immunology ; Blotting, Western ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; Female ; Genetic Vectors ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Plague ; immunology ; prevention & control ; Plague Vaccine ; genetics ; immunology ; Plasmids ; Pore Forming Cytotoxic Proteins ; genetics ; immunology ; Protein Engineering ; methods ; Recombinant Fusion Proteins ; genetics ; immunology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Survival Analysis ; Vaccines, Subunit ; genetics ; immunology ; Yersinia pestis ; growth & development ; immunology

OBJECTIVEChlamydia psittaci is an avian respiratory pathogen and zoonotic agent. The wide prevalence of C. psittaci poses a threat to the poultry industry and its employees. However, few commercial kits are available for detecting avian antibodies excluding the in-house ELISA kit. In this study, we developed a novel ELISA kit for detecting antibodies against C. psittaci based on the N-terminal fragment of polymorphic outer membrane protein D (PmpD-N) as the coating antigen.

METHODSThe antigen concentrations, primary antibody, and cut-off value were determined and optimized. The ELISA, designated PmpD-N ELISA, was assessed for sensitivity, specificity, and concordance using sera samples from 48 experimentally infected and 168 uninfected SPF chickens.

RESULTSThe sensitivity and specificity of PmpD-N ELISA were 97.9%, 100%, respectively, while the concordance was 98.1% as compared to that of MOMP-ELISA. No cross-reaction with positive sera for other avian pathogens was found. Using PmpD-N ELISA, 799/836 clinical samples were positive, including 93.0% and 98.1% positivity in layers and broilers, respectively.

CONCLUSIONThese data indicate that indirect ELISA with PmpD-N as the antigen candidate is a promising approach for the surveillance of C. psittaci infection.

Animals ; Bacterial Proteins ; analysis ; Chickens ; Chlamydophila psittaci ; genetics ; immunology ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; veterinary ; Membrane Proteins ; analysis ; Poultry Diseases ; diagnosis ; microbiology ; Psittacosis ; diagnosis ; microbiology ; veterinary ; Sensitivity and Specificity

OBJECTIVETo construct prokaryotic expression systems of ltB/ctB-lipL41/1 fusion genes, identify immunogenic and adjuvant activities of the products as well as to understand the frequencies of lipL41 gene that carrying and expressing in L. interrogans wild strains and specific antibody levels in sera from patients with leptospirosis.

METHODSPolymerase chain reaction (PCR) with linking primer was applied to construct the fusion genes ltB-lipL41/1 and ctB-lipL41/1. By routine molecular biological techniques, prokaryotic expression systems of the two fusion genes were constructed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to examine expression of the target recombinant proteins rLTB-rLipL41/1 and rCTB-rLipL41/1. Both western blot and Ganglioside-enzyme linked immunosorbent assay (GM-ELISA) were used while immunogenic and adjuvant activities of rLTB-rLipL41/1 and rCTB-rLipL41/1 were measured. PCR and MAT were performed to detect lipL41 gene and expression of the gene in 97 wild strains of L. interrogans, respectively. Antibodies against product of lipL41 gene in serum samples from 228 leptospirosis patients were detected by ELISA.

RESULTSIn comparison with reported corresponding sequences, the similarities of ltB-lipL41/1 and ctB-lipL41/1 fusion genes to nucleotide and putative amino acid sequence were 99.6%-99.9% and 99.8%-100%, respectively. Expression outputs of both rLTB-rLipL41/1 and rCTB-rLipL41/1, mainly presenting with inclusion body, consisting approximate 10% of the total bacterial proteins. Both rLTB-rLipL41/1 and rCTB-rLipL41/1 could combine rabbit anti-rLipL41/1 serum as well as bovine GM1, respectively. 87.6% of the L. interrogans wild strains(85/97) having lipL41 gene while 84.5% (82/97) of the wild strains with rLipL41/1 or rLipL41/2 antiserum were positive for MAT with titers of 1:4-1:128. 84.6% (193/ 228), 78.5% (179/228) from the patients' serum samples were positive for rLipL41/1 and rLipL41/2 antibodies, respectively.

CONCLUSIONltB-lipL41/1 and ctB-lipL41/1 fusion genes and their prokaryotic expression systems were successfully constructed in this study. The two expressed fusion proteins showed qualified immunogenic and adjuvant activities. lipL41 gene was extensively distributed and frequently expressed in different serogroups of L. interrogans. rLTB-rLipL41/1 or rCTB-rLipL41/1 seemed to have had good potential to serve as an antigen in L. interrogans genus-specific vaccine.

Amino Acid Sequence ; Animals ; Antibody Specificity ; Antigens, Bacterial ; biosynthesis ; chemistry ; genetics ; immunology ; Cattle ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli Proteins ; genetics ; Genetic Engineering ; methods ; Humans ; Leptospira interrogans ; genetics ; physiology ; Leptospirosis ; immunology ; Polymerase Chain Reaction ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics ; immunology ; Sequence Analysis, DNA