Acinetobacter baumannii (A. Baumannii) is an emerging opportunistic pathogen responsible for hospital-acquired infections, and which now constitutes a sufficiently serious threat to public health to necessitate the development of an effective vaccine. In this study, a recombinant fused protein named OmpK/Omp22 and two individual proteins OmpK and Omp22 were obtained using recombinant expression and Ni-affinity purification. Groups of BALB/c mice were immunized with these proteins and challenged with a clinically isolated strain of A. baumannii. The bacterial load in the blood, pathological changes in the lung tissue and survival rates after challenge were evaluated. Mice immunized with OmpK/Omp22 fused protein provided significantly greater protection against A. baumannii challenge than those immunized with either of the two proteins individually. The results provide novel clues for future design of vaccines against A. baumannii.
Acinetobacter Infections ; pathology ; prevention & control ; Acinetobacter baumannii ; genetics ; immunology ; Animals ; Antibodies, Bacterial ; blood ; Bacterial Load ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; Bacterial Vaccines ; immunology ; Disease Models, Animal ; Female ; Mice, Inbred BALB C ; Pneumonia, Bacterial ; pathology ; prevention & control ; Recombinant Fusion Proteins ; genetics ; immunology

Serologic tests are widely accepted for diagnosing Toxoplasma gondii but purification and standardization of antigen needs to be improved. Recently, surface tachyzoite and bradyzoite antigens have become more attractive for this purpose. In this study, diagnostic usefulness of 3 recombinant antigens (SAG1, SAG2, and SAG3) were evaluated, and their efficacy was compared with the available commercial ELISA. The recombinant plasmids were transformed to JM109 strain of Escherichia coli, and the recombinants were expressed and purified. Recombinant SAG1, SAG2, and SAG3 antigens were evaluated using different groups of sera in an ELISA system, and the results were compared to those of a commercial IgG and IgM ELISA kit. The sensitivity and specificity of recombinant surface antigens for detection of anti-Toxoplasma IgG in comparison with commercially available ELISA were as follows: SAG1 (93.6% and 92.9%), SAG2 (100.0% and 89.4%), and SAG3 (95.4% and 91.2%), respectively. A high degree of agreement (96.9%) was observed between recombinant SAG2 and commercial ELISA in terms of detecting IgG anti-Toxoplasma antibodies. P22 had the best performance in detecting anti-Toxoplasma IgM in comparison with the other 2 recombinant antigens. Recombinant SAG1, SAG2, and SAG3 could all be used for diagnosis of IgG-specific antibodies against T. gondii.
Antibodies, Protozoan/*blood ; Antigens, Protozoan/diagnostic use/*genetics ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Membrane Glycoproteins/*genetics ; Protozoan Proteins/*genetics ; Recombinant Proteins/diagnostic use/immunology ; Sensitivity and Specificity ; Toxoplasma/immunology ; Toxoplasmosis/blood/*diagnosis

Amplification of the 16S rRNA gene from a blood sample obtained from a dog in southeastern Brazil was used to confirm a naturally acquired Ehrlichia (E.) canis infection. Following isolation and culturing of the new bacterial strain called Uberlandia, partial sequences of the dsb and p28 genes were obtained. The dsb partial sequence of the novel strain was 100% similar to dsb gene sequences of E. canis obtained from different geographic areas around the world. Conversely, the p28 partial sequence for the E. canis Uberlandia strain differed at several nucleotides from other sequences available in GenBank. To confirm the antigenic profile of the Uberlandia strain, an indirect immunofluorescence assay against E. canis antigens was performed using dog sera collected from two different areas in Brazil (Uberlandia and Sao Paulo). The results suggest that both antigens were able to identify animals seropositive for E. canis in Brazil since these Brazilian strains appear to be highly conserved.
Animals ; Antigens, Bacterial/blood/*diagnostic use ; Bacterial Outer Membrane Proteins/genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Base Sequence ; Brazil ; Dog Diseases/diagnosis/*microbiology ; Dogs ; Ehrlichia canis/*genetics/*immunology/isolation & purification ; Ehrlichiosis/diagnosis/microbiology/*veterinary ; Fluorescent Antibody Technique, Indirect/veterinary ; Male ; Molecular Sequence Data ; Polymerase Chain Reaction/veterinary ; RNA, Ribosomal, 16S/genetics/metabolism ; Sequence Alignment/veterinary

OBJECTIVETo investigate the effect of protein transduction domain-hepatitis B virus core antigen (CTP-HBcAg18-27)-Tapasin fusion protein-induced specific cytotoxic T lymphocyte (CTL) response on hepatitis B virus (HBV) replication in HBV transgenic mice.

METHODSTwenty HBV-transgenic mice were randomly divided into two groups for a 3-week course of once weekly subcutaneous immunizations with either CTP-HBcAg18-27-Tapasin fusion protein or CTP-HBcAg18-27. Mice administered isotonic saline served as blank controls. Expressions of cytokines in splenocytes were analyzed by flow cytometry. Serum levels of hepatitis B surface antigen (HBsAg) and HBV DNA were determined by microparticle enzyme immunoassay and real-time fluorescent PCR assay, respectively. Expression of HBsAg in hepatic tissues was detected by immunohistochemistry.

RESULTSImmunization with 100 mug of CTP-HBcAg18-27-Tapasin fusion protein led to a significant increase in proportions of CTLs in spleen (2.70%+/-0.20% vs. 50 mug of CTP-HBcAg18-27-Tapasin: 1.66%+/-0.53%, 50 mug of CTP-HBcAg18-27: 1.26%+/-0.56%, and blank controls: 0.75%+/-0.71%; F = 741.45, P = 0.000) and up-regulation of inflammatory cells in hepatic tissue. In addition, both immunizations of CTP-HBcAg18-27-Tapasin led to significant decreases in serum HBsAg and HBV DNA levels compared to those in the CTP-HBcAg18-27 group.

CONCLUSIONHBV-related modification of the expression of the molecular chaperone Tapasin may affect its interaction with intracellular antigen peptides, thereby leading to increases the number of specific CTLs in the spleen, decreases in serum HBsAg and HBV DNA levels, and down-regulation of HBsAg expression in hepatic tissue. These results obtained in HBV-transgenic mice suggest that the CTP-HBcAg18-27-Tapasin fusion protein has anti-HBV activity.

Animals ; DNA, Viral ; blood ; Female ; Hepatitis B ; immunology ; Hepatitis B Core Antigens ; genetics ; Hepatitis B Surface Antigens ; blood ; Hepatitis B virus ; physiology ; Male ; Membrane Transport Proteins ; genetics ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Recombinant Fusion Proteins ; genetics ; immunology ; T-Lymphocytes, Cytotoxic ; immunology ; Transfection ; Virus Replication

OBJECTIVETo determine the distribution and sequence conservation of pagC gene in Salmonella paratyphi A isolates, and the immunogenicity and immunoprotection of its recombinant expression products (rPagC).

METHODSThe distribution of pagC gene in Salmonella paratyphi A isolates and its sequence conservation were examined by PCR and sequencing. A prokaryotic expression system of pagC gene was constructed and the expressed rPagC was extracted by Ni-NTA affinity chromatography. SDS-PAGE and Bio-Rad Gel Image Analyzer were applied to examine the expression and yield of rPagC. The antigenicity and immunoreactivity of rPagC were detected by immunodiffusion test, ELISA and Western Blot assay. The immunoprotective effect of rPagC against infection of Salmonella paratyphi A in mice was determined, while the agglutinative effect of sera from rPagC-immunized mice was measured by micro-Widal's test.

RESULTSAll the Salmonella paratyphi A isolates tested had the pagC gene, the similarity of nucleotide and amino acid sequences was 99.1 %-100 % and 98.4 %-100 %, respectively. The constructed prokaryotic expression system expressed rPagC with high efficiency. The rPagC immunized rabbit produced a high level antibody and it also combined with antiserum against whole cell of S. paratyphi A to generate a positive Western hybridization signal. ELISA results indicated that 97.1 % (66/68) paratyphoid patients infected with Salmonella paratyphi A were positive for rPagC antibody in their serum specimens. When mice were immunized with 100 μg or 200 μg rPagC, the immunoprotective rates were 73.3 % (11/15) or 86.7 % (13/15), respectively. The sera from rPagC-immunized mice offered 1:10-1:40 agglutination titers with the H antigens of Salmonella paratyphi A and Salmonella typhi.

CONCLUSIONPagC gene has an extensive distribution in Salmonella paratyphi A isolates. rPagC can be used as the candidate antigen in genetic engineering vaccine due to its fine immunogenicity and powerful immunoprotective effect.

Agglutination Tests ; Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; genetics ; immunology ; Bacterial Proteins ; genetics ; immunology ; Bacterial Vaccines ; Membrane Proteins ; genetics ; immunology ; Mice ; Rabbits ; Recombinant Proteins ; genetics ; immunology ; Salmonella paratyphi A ; genetics ; immunology ; Sequence Homology, Amino Acid ; Sequence Homology, Nucleic Acid

The outer membrane proteins (OMPs) of Brucella (B.) abortus have been extensively studied, but their immunogenicity and protective ability against B. abortus infection are still unclear. In the present study, B. abortus Omp28, a group 3 antigen, was amplified by PCR and cloned into a maltose fusion protein expression system. Recombinant Omp28 (rOmp28) was expressed in Escherichia coli and was then purified. Immunogenicity of rOmp28 was confirmed by Western blot analysis with Brucella-positive mouse serum. Furthermore, humoral- or cell-mediated immune responses measured by the production of IgG1 or IgG2a in rOmp28-immunized mice and the ability of rOmp28 immunization to protect against B. abortus infection were evaluated in a mouse model. In the immunogenicity analysis, the mean titers of IgG1 and IgG2a produced by rOmp28-immunized mice were 20-fold higher than those of PBS-treated mice throughout the entire experimental period. Furthermore, spleen proliferation and bacterial burden in the spleen of rOmp28-immunized mice were approximately 1.5-fold lower than those of PBS-treated mice when challenged with virulent B. abortus. These findings suggest that rOmp28 from B. abortus is a good candidate for manufacturing an effective subunit vaccine against B. abortus infection in animals.
Animals ; Antibodies, Bacterial/blood ; Blotting, Western/veterinary ; Brucella Vaccine/*immunology ; Brucella abortus/*immunology ; Brucellosis, Bovine/*immunology/microbiology/*prevention & control ; Cattle ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel/veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Immunization/veterinary ; Immunoglobulin G/blood ; Immunoglobulin Isotypes/blood ; Membrane Proteins/genetics/*immunology ; Mice ; Mice, Inbred BALB C ; Models, Animal ; Recombinant Proteins/genetics/immunology ; Vaccines, Subunit/immunology

In Iran, Plasmodium vivax is responsible for more than 80% of the infected cases of malaria per year. Control interventions for vivax malaria in humans rely mainly on developed diagnostic methods. Recombinant P. vivax apical membrane antigen-1 (rPvAMA-1) has been reported to achieve designing rapid, sensitive, and specific molecular diagnosis. This study aimed to perform isolation and expression of a rPvAMA-1, derived from Iranian patients residing in an endemic area. Then, the diagnostic efficiency of the characterized Iranian PvAMA-1 was assessed using an indirect ELISA method. For this purpose, a partial region of AMA-1 gene was amplified, cloned, and expressed in pET32a plasmid. The recombinant His-tagged protein was purified and used to coat the ELISA plate. Antibody detection was assessed by indirect ELISA using rPvAMA-1. The validity of the ELISA method for detection of anti-P. vivax antibodies in the field was compared to light microscopy on 84 confirmed P. vivax patients and compared to 84 non-P. vivax infected individuals. The ELISA cut-off value was calculated as the mean+2SD of OD values of the people living in malaria endemic areas from a south part of Iran. We found a cut-off point of OD=0.311 that showed the best correlation between the sera confirmed with P. vivax infection and healthy control sera. A sensitivity of 81.0% and specificity of 84.5% were found at this cut off titer. A good degree of statistical agreement was found between ELISA using rPvAMA-1 and light microscopy (0.827) by Kappa analysis.
Antibodies, Protozoan/blood/immunology ; Antigens, Protozoan/*blood/genetics/immunology ; Diagnostic Tests, Routine/*methods ; Enzyme-Linked Immunosorbent Assay/*methods ; Female ; Humans ; Iran ; Malaria, Vivax/blood/*diagnosis/immunology/*parasitology ; Male ; Membrane Proteins/blood/genetics/immunology ; Plasmodium vivax/isolation & purification/*physiology ; Protozoan Proteins/blood/genetics/immunology ; Sensitivity and Specificity

OBJECTIVETo express and purify Hap protein of nontypeable Haemophilus influenzae (NTHi) in prokaryotic system, and study its immunogenicity and adhesive activity.

METHODHap protein was expressed in E.coli BL21 with pET32a (+)-Hap and purified by affinity chromatography. The adhesive activity of the recombinant Hap protein was observed in competitive adhesion assay using scanning electron microscope and bacterial counting. BALB/C mice were immunized intranasally with the purified recombinant Hap protein and cholera toxin B subunit (CT-B), and anti-Hap IgA and IgG were detected by enzyme-linked immunosorbent assay.

RESULTSSDS-PAGE analysis showed a single band of the target protein, whose purity reached 85% according to the result of Gel analysis software. The concentration of the protein was 3.2 g/L after ultrafiltration and condensation. Competitive adhesion assay showed that compared with control group, the recombinant Hap protein significantly inhibited the adhesion of NTHi to ECM (P<0.01). Compared with Hap immunization alone, immunization with Hap combined with CT-B resulted in significantly higher titers of anti-Hap IgG and IgA in mice (P<0.05).

CONCLUSIONHighly purified recombinant Hap protein has been obtained in a prokaryotic system and shows good immunogenic and adhesive activities. These results will establish the basis for further study of NTHi vaccine.

Adhesiveness ; Animals ; Bacterial Outer Membrane Proteins ; biosynthesis ; genetics ; immunology ; Cholera Toxin ; immunology ; Escherichia coli ; genetics ; metabolism ; Haemophilus Infections ; prevention & control ; Haemophilus influenzae ; metabolism ; Immunization ; Immunoglobulin A ; blood ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Serine Endopeptidases ; biosynthesis ; genetics ; immunology

OBJECTIVETo investigate the antigenicity of recombinant Chlamydia trachomatis (Ct) OmcBc protein and search for the new target for early diagnosis of Chlamydia infection and Chlamydia vaccine development.

METHODSThe C fragment of OmcB encoding the amino acids from T270 to T553 was amplified from Chlamydia serovar D genomic DNA. The pGEX-6p-Ct OmcBc expression plasmid was constructed and transformed into E.coli XL-1blue. The expression of recombinant Ct OmcBc protein was induced by IPTG. Serum samples were collected from 120 patients with urogenital Chlamydia infection. The antiserum samples were collected from 7 New Zealand white rabbits and 5 Balb/C mice immunized subcutaneously and intraperitoneally with Ct serovar D inactivated EB, respectively, and from 9 Balb/C mice intranasally infected with Ct serovar D live EB. The anti-Chlamydia specific antibody were titrated by an immunofluorescence assay (IFA). The reactivity of the recombinant OmcBc protein with all the above antisera was detected by ELISA.

RESULTSThe pGEX-6p-Ct OmcBc expression plasmid was successfully constructed. DNA sequencing showed that the inserted OmcBc was about 852 bp, encoding a protein with 284 amino acids. The expression of the recombinant GST-OmcBc was induced by IPTG, producing a fusion protein with a molecular weight of about 57 kD. The titer of the specific antibodies to Chlamydia in all the antisera was high. ELISA results showed strong reactivities of the recombinant GST-OmcBc fusion protein with all the above antisera.

CONCLUSIONSOmcBc protein is an immunodominant protein of Chlamydia. The recombinant GST-OmcBc with strong antigenicity may provide a basis for further study of early diagnosis of chlamydia infection and development of Chlamydia vaccine.

Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; immunology ; metabolism ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; Chlamydia trachomatis ; genetics ; immunology ; metabolism ; Cloning, Molecular ; Genes, Bacterial ; Humans ; Immune Sera ; immunology ; Mice ; Mice, Inbred BALB C ; Plasmids ; Rabbits

OBJECTIVETo study the correlation between hepatocellular carcinoma (HCC) and serum Golph2 protein.

METHODSGolph2 gene was cloned by RT-PCR using RNA from WBF44 cell line as template, the point mutations of the cloned sequence were corrected by PCR, then the gene (1206 bp) was cloned into pET-21 plasmid, and the resulted plasmid was transformed into E.coli DH5a. The expression of 6xHis and Golph2 fusion protein was induced by isopropylthio-beta-D-galactoside (IPTG). The expression of fusion protein was detected by SDS-PAGE and Western blot, and was purified by Ni NTA chelating agarose. The rabbit antibody against Golph2 protein was obtained by immunizing 2 rabbits with the purified Golph2 protein. The specificity and titer of the antibody was determined by Western-blot and ELISA respectively. Sandwich ELISA was used to detect the level of serum Golph2 protein.

RESULTSThere were two replacement mutation and 1 deletion mutation in the cloned sequence contrasted to NM177937 in Genbank, including 644(T-->C, L-->P) , 970 (G-->A, V-->I) and 802 G deletion. The sequence was completely reversed by PCR. The sequence of Golph2 gene cloned into expression vector was confirmed by DNA sequencing. SDS-PAGE and Western blot analysis showed that Golph2 protein was expressed in E.coli DH5a. The antiserum could bind to the 52 kD recombinant protein and serum 73 kD protein specifically. The mean A450 value of ELISA for serum Golph2 protein were significantly higher in HCC and other liver diseases than that in control groups. The sensitivity and specificity for HCC were 44.5% and 82.0%, respectively, at the cut off value is more than or equal to 0.40.

CONCLUSIONThe polyclonal antibody against Golph2 protein is specific. The level of serum Golph2 is significantly higher in patients with HCC and other liver diseases than that in healthy controls.

Animals ; Antibodies, Monoclonal ; analysis ; immunology ; Base Sequence ; Biomarkers, Tumor ; blood ; Carcinoma, Hepatocellular ; diagnosis ; metabolism ; pathology ; Cell Line, Tumor ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; methods ; Escherichia coli ; genetics ; Genetic Vectors ; genetics ; Humans ; Liver Neoplasms ; diagnosis ; metabolism ; pathology ; Male ; Membrane Proteins ; biosynthesis ; blood ; genetics ; immunology ; metabolism ; Molecular Sequence Data ; Polymerase Chain Reaction ; Rabbits