Journal of Microbiology

Journal Articles

Anti-inflammatory and anti-oxidative effect of Korean propolis on Helicobacter pylori-induced gastric damage in vitro: Moon-Young Song , Da-Young Lee , Eun-Hee Kim; J. Microbiol. 2020;58(10):878-885. Published online September 2, 2020; DOI: https://doi.org/10.1007/s12275-020-0277-z

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27 Citations

Abstract: Helicobacter pylori, present in the stomach lining, is a Gramnegative bacterium that causes various gastrointestinal diseases, including gastritis and peptic ulcers. Propolis is a natural resinous substance collected from a variety of plants, and contains several natural bioactive substances. The aim of this study was to investigate the anti-inflammatory and antioxidative effects of Korean propolis on H. pylori-induced damage in the human adenocarcinoma gastric cell line. The propolis used in this study was obtained from the Korea Beekeeping Association in South Korea. The expression of pro-inflammatory interleukins (ILs), such as IL-8, IL-12, IL-1β, tumor necrosis factor alpha, cyclooxygenase-2, and inducible nitric oxide synthase, which was increased after H. pylori infection, significantly decreased in a dose-dependent manner upon pretreatment with Korean propolis, because of the suppression of mitogen-activated protein kinases and nuclear factor κB pathway. The anti-oxidative activity of propolis was assessed using the 2,2-diphenyl-1-picrylhydrazyl hydrate free radical assay. Korean propolis showed significant anti-oxidative effects via reactive oxygen species scavenging. In addition, pretreatment with Korean propolis upregulated the expression of anti-oxidant enzymes through Nrf2 signaling activation. These findings indicate that the use of Korean propolis, which has anti-inflammatory and anti-oxidative effects, can be promising for the prevention of H. pylori-induced gastric damage.

Development of a real-time loop-mediated isothermal amplification method for the detection of severe fever with thrombocytopenia syndrome virus: Jae Woong Lee , Yu-Jung Won , Lae Hyung Kang , Sung-Geun Lee , Seung-Won Park , Soon-Young Paik; J. Microbiol. 2020;58(8):711-715. Published online May 18, 2020; DOI: https://doi.org/10.1007/s12275-020-0109-1

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9 Citations

Abstract: Severe fever with thrombocytopenia syndrome (SFTS) is being reported annually in South Korea since its first detection there in 2010. The causal agent is a negative-strand RNA virus 80–100 nm in diameter. It causes fever, thrombocytopenia, leukocytopenia, gastrointestinal symptoms, and neural symptoms. The mortality rate of SFTS was 32.6% among 172
case
s reported from 2012 to 2015 in South Korea. Thus, is necessary to develop an effective diagnostic method that selectively identifies the isolates circulating in South Korea. The real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay is a simple, rapid, and sensitive approach for molecular diagnosis. Here, we designed novel primers for this assay and found that the technique had very high specificity, sensitivity, and efficiency. This real-time RTLAMP approach using the novel primers developed herein can be applied for early diagnosis of SFTSV strains in South Korea to reduce the mortality rate of SFTS.

IgG and IgM responses to human papillomavirus L1 virus-like particle as a function of dosing schedule and vaccine formulation: Min-Hye Park , Ji Won You , Hyoung Jin Kim , Hong-Jin Kim; J. Microbiol. 2019;57(9):821-827. Published online August 27, 2019; DOI: https://doi.org/10.1007/s12275-019-9308-z

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4 Citations

Abstract: Most commercialized virus-like particle (VLP) vaccines use aluminum salt as adjuvant, even though VLPs provoke adequate antibody responses without adjuvant. We do not have detailed knowledge of how adjuvant affects the profile of anti- VLP antibodies. Meanwhile, there is evidence that differences between vaccination protocols influence the glycosylation of antibodies, which may alter their effector functions. In the present study a murine model was used to investigate the effects of dosing schedule and adjuvant on the antibody profiles and glycosylation levels of antigen-specific antibody responses to human papillomavirus type 16 L1 (HPV16 L1) VLPs. Mice received subcutaneously 2,000 ng of antigen divided into 4 or 7 doses. The HPV16 L1 VLPs elicited > 4 log10 anti-HPV16 L1 IgG titers without adjuvant, and aluminum hydroxide as adjuvant increased IgG titers 1.3- to 4-fold and reduced the anti-HPV16 L1 IgG2a / anti-HPV16 L1 IgG1 ratio value (use of aluminum hydroxide reduced the ratio of the IgG2a). Immunization with HPV16 L1 VLPs in combination with Freund’s adjuvant enhanced IgG titers 5- to 12- fold. Seven-dose immunization markedly increased anti- HPV16 L1 IgM titers compared to four-dose immunization, as well as increasing the proportion of glycosylated antibodies. Our results suggest that antibody glycosylation can be controlled immunologically, and IgG and IgM profiles and glycosylation profiles of the vaccine-induced antibodies can be used as indicators reflecting the vaccine characteristics. These
results
indicate that the HPV16 L1 VLP dosing schedule can affect the quality of antigen-specific antibody responses. We suggest that dosing schedules should be noted in vaccination protocols for VLP-based vaccines.

Research Support, Non-U.S. Gov't

Immunological charaterization of monoclonal antibodies used in rapid influenza diagnostic test for detection of the 2009 pandemic influenza A(H1N1)pdm09 infection: Hwajung Yi , Mi-Seon Lee , Joo-Yeon Lee , Hae Kyung Lee , Chun Kang; J. Microbiol. 2015;53(2):166-175. Published online January 28, 2015; DOI: https://doi.org/10.1007/s12275-015-4642-2

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Abstract: Since the 2009 pandemic, monoclonal antibodies (mAbs) for rapid influenza diagnostic tests (RIDT) have been developed for specific diagnostics of pandemic viral infection. Most of the mAbs were poorly characterized because of urgency during the pandemic. Further characterization of the mAbs for RIDTs would be beneficial for understanding the immunological properties of the pandemic virus and utilizing the mAbs for other research purposes. In this study, it was confirmed that two mAbs (I38 and D383) in an RIDT for H1N1pdm09 diagnostics were able to detect H1N1pdm09 virus through enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). Also, the two mAbs exhibited reactivity to hemagglutinins (HAs) of both the H1N1pdm09 and 1918 H1N1 viruses; therefore, the RIDT using the mAbs could detect HAs of H1N1pdm09 and also HAs of 1918 H1N1-like strains. In an extension to our previous study, the epitopes (Sa antigenic site and the interface area of F?and vestigial esterase subdomains on the HA1 domain of HA of H1N1pdm09) recognized by the mAbs were corroborated in depth by IFA with escape-mutants from the mAbs and mapping of the epitopes on the crystal structure of human H1N1 viral HAs. Collectively, these results imply that the mAbs for the RIDT may be suitable for use in studying the immunological properties of H1N1pdm09 viruses and that the Sa antigenic site and the interface area between F?and vestigial esterase subdomains on influenza viral HA recognized by the mAbs are immunologically conserved regions between H1N1pdm09 and 1918 H1N1.

Journal Article

Anti protein A antibody-gold nanorods conjugate: a targeting agent for selective killing of methicillin resistant Staphylococcus aureus using photothermal therapy method: Rasoul Shokri , Mojtaba Salouti , Rahim Sorouri Zanjani; J. Microbiol. 2015;53(2):116-121. Published online January 28, 2015; DOI: https://doi.org/10.1007/s12275-015-4519-4

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24 Citations

Abstract: The high prevalence of methicillin resistant Staphylococcus aureus (MRSA) and developing resistance to antibiotics requires new approaches for treatment of infectious diseases due to this bacterium. In this study, we developed a targeting agent for selective killing of MRSA using photothermal therapy method based on anti protein A antibody and gold nanorods (GNRs). Polystyrene sulfonate (PSS) coated GNRs were conjugated with anti protein A antibody. The FT-IR and UV-vis analyses approved the formation of anti protein A antibody-gold nanorods conjugate. In vitro study of photothermal therapy showed 82% reduction in the MRSA cells viability which was significantly greater than the ablation effect of free GNRs and laser alone. Significant accumulation of anti protein A antibody-GNRs in the infected muscle in comparison with normal muscle approved the targeting ability of new agent. In vivo study of photothermal therapy resulted in a significant reduction (73%) in the bacterial cells viability in the infected mouse model. These results demonstrated the ability of anti protein A antibody-GNRs conjugate in combination with NIR laser energy for selective killing of MRSA in mouse model.

Validation Study

Comparison of JEV Neutralization Assay Using Pseudotyped JEV with the Conventional Plaque-Reduction Neutralization Test: Hee-Jung Lee , Kyung-Il Min , Ki Hoon Park , Hyo Jung Choi , Min-Kyoung Kim , Chi-Young Ahn , Young-Jin Hong , Young Bong Kim; J. Microbiol. 2014;52(5):435-440. Published online March 7, 2014; DOI: https://doi.org/10.1007/s12275-014-3529-y

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18 Citations

Abstract: We previously reported the development of a neutralization assay system for evaluating Japanese Encephalitis Virus (JEV) neutralizing antibody (NAb) using pseudotyped-JEV (JEV- PV). JEV-PV-based neutralization assay offers several advan-tages compared with the current standard plaque-reduc-tion neutralization test (PRNT), including simplicity, safety, and speed. To evaluate the suitability of the JEV-PV assay as new replacement neutralization assay, we compared its repeatability, reproducibility, specificity, and correlated its results with those obtained using the PRNT. These analyses showed a close correlation between the results obtained with the JEV-PV assay and the PRNT, using the 50% plaque re-duction method as a standard for measuring NAb titers to JEV. The validation results met all analytical acceptance criteria. These results suggest that the JEV-PV assay could serve as a safe and simple method for measuring NAb titer against JEV and could be used as an alternative approach for assaying the potency of JEV neutralization.

Research Support, Non-U.S. Gov'ts

Fine Mapping of a Foot-and-Mouth Disease Virus Epitope Recognized by Serotype-Independent Monoclonal Antibody 4B2: Yongzhong Yu , Haiwei Wang , Lei Zhao , Chunyuan Zhang , Zhigang Jiang , Li Yu; J. Microbiol. 2011;49(1):94-101. Published online March 3, 2011; DOI: https://doi.org/10.1007/s12275-011-0134-1

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26 Citations

Abstract: VP2 is a structural protein of the foot-and-mouth disease virus (FMDV). In this study, a FMDV serotype-independent monoclonal antibody (MAb), 4B2, was generated. By screening a phage-displayed random 12-peptide library, we found positive phages displaying the consensus motif ETTXLE (X is any amino acid (aa)), which is highly homologous to 6ETTLLE11 at the N-terminus of the VP2 protein. Subsequently, a series of GST-fusion proteins expressing a truncated N-terminus of VP2 were examined by western blot analysis using the MAb 4B2. The results indicated that the motif 6ETTLLE11 of VP2 may be the minimal requirement of the epitope recognized by 4B2. Moreover, a 12-aa peptide 2KKTEETTLLEDR13 was shown to be the minimal unit of the epitope with maximal binding activity to 4B2. Alanine-scanning analysis demonstrated thatThr7, Thr8, and Leu10 are the functional residues of the 4B2 epitope Glu6 and Leu9 are required residues, and Glu11 plays a crucial role in the binding of MAb 4B2. The fine mapping of the epitope indicated that MAb 4B2 has the potential to be used in FMDV diagnosis.

Development of a Latex Agglutination Test for Norovirus Detection: Heetae Lee , YoungBin Park , Misoon Kim , Youngmee Jee , Doo-sung Cheon , Hae Sook Jeong , GwangPyo Ko; J. Microbiol. 2010;48(4):419-425. Published online August 20, 2010; DOI: https://doi.org/10.1007/s12275-010-0071-4

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9 Citations

Abstract: Norovirus (NoV) is the leading cause of acute gastroenteritis worldwide. Currently, reverse transcription polymerase chain reaction (RT-PCR) is used commonly to detect NoVs in both clinical and environmental samples. However, RT-PCR requires expensive equipment and cannot be performed on site. In this study, a latex agglutination test (LAT) using antibody-labeled latex beads for detecting NoVs was developed. Two kinds of polyclonal antibodies, one generated from synthetic peptides and the other from E. coli-expressed NoV capsid proteins, were used to develop the LAT. Each of these polyclonal antibodies was immobilized on the surface of latex beads and tested for the ability to detect NoVs. Under optimized conditions, our LAT detected GII.4 NoV at concentrations as low as 3.3×105 RT-PCR units/ml in stool samples. The detection limit for the LAT was approximately 1.7×103 RT-PCR units. Forty-eight stool samples were tested for NoVs using this LAT. In comparison with an RT-PCR assay, the sensitivity and specificity of the LAT were 35% and 100%, respectively. With further optimization, this LAT used with appropriate antibodies could be applied for convenient detection of NoVs in clinical diagnosis and food monitoring.

Identification of a Novel Linear B-Cell Epitope in the M Protein of Avian Infectious Bronchitis Coronaviruses: Junji Xing , Shengwang Liu , Zongxi Han , Yuhao Shao , Huixin Li , Xiangang Kong; J. Microbiol. 2009;47(5):589-599. Published online October 24, 2009; DOI: https://doi.org/10.1007/s12275-009-0104-z

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16 Citations

Abstract: This report describes the identification of a novel linear B-cell epitope at the C-terminus of the membrane (M) protein of avian infectious bronchitis virus (IBV). A monoclonal antibody (MAb) (designated as 15E2) against the IBV M protein was prepared and a series of 14 partially-overlapping fragments of the IBV M gene were expressed with a GST tag. These peptides were subjected to enzyme-linked immunosorbent assay (ELISA) and western blotting analysis using MAb 15E2 to identify the epitope. A linear motif, 199FATFVYAK206, which was located at the C-terminus of the M protein, was identified by MAb 15E2. ELISA and western blotting also showed that this epitope could be recognized by IBV-positive serum from chicken. Given that 15E2 showed reactivity with the 199FATFVYAK206 motif, expressed as a GST fusion protein, in both western blotting and in an ELISA, we proposed that this motif represented a linear B-cell epitope of the M protein. The 199FATFVYAK206 motif was the minimal requirement for reactivity as demonstrated by analysis of the reactivity of 15E2 with several truncated peptides that were derived from the motif. Alignment and comparison of the 15E2-defined epitope sequence with the sequences of other coronaviruses indicated that the epitope is well conserved among chicken and turkey coronaviruses. The identified epitope should be useful in clinical applications and as a tool for the further study of the structure and function of the M protein of IBV.

Journal Articles

Molecular Cloning and Characterization of a Single-Chain Variable Fragment Antibody Specific for Benzoylecgonine Expressed in Escherichia coli: Kenichiro Mori , Youn Uck Kim; J. Microbiol. 2008;46(5):571-578. Published online October 31, 2008; DOI: https://doi.org/10.1007/s12275-008-0123-1

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2 Citations

Abstract: Benzoylecgonine is a major metabolite of cocaine. We generated hybridoma cells (C1303) producing antibenzoylecgonine monoclonal antibody (mAb) with a single-chain variable fragment (scFv) and an antigenbinding domain from the C1303 cells. Genes encoding an scFv antibody and constant region (Fc) were amplified from a cDNA library of C1303 cells using PCR. The two frameworks built for scFv and scFv-Fc consisted of HL [(heavy chain variable region, VH) - linker - (light chain variable region, VL)] and HL-Fc, respectively. A 45 base-pair-long sequence encoding (Gly4-Ser)3 was used as the linker, and the mouse IgG1 constant region sequence (225 amino acids) was used as the Fc domain. These two types of recombinant Abs were determined to be 750 bp in length (which corresponds to a 30 kDa protein) in the HL and 1,432 bp in length (which corresponds to a 65 kDa protein) in the HL-Fc, respectively. The parental Ab and HL-Fc affinities against benzoylecgonine were measured by ELISA and found to be nearly equal to the Ab concentration. We were also able to measure HL affinity using an agarose diffusion assay (Ouchterlony test). The affinity of the recombinant single-chain antibody against benzoylecgonine was sufficiently comparable to that of the parent antibodies to be used for the immunodetection of specific drug compounds or the detoxification of drug abusers by immunotherapy.

Prevalence of Antibodies in Response to Legionella Species, Analysis of a Healthy Population from Jeollanam-do Province, Korea: Hae Kyung Lee , Mi Kyeong Woo , Yong In Ju , Soo Jin Baek , Hyeon Je Song , Jin Su Choi , Sun Seog Kweon , Doo Young Jeon , Yeon Ho Kang; J. Microbiol. 2008;46(2):160-164. Published online June 11, 2008; DOI: https://doi.org/10.1007/s12275-007-0181-9

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14 Citations

Abstract: Seroepidemological investigation of antibodies to Legionella species in 500 healthy individuals from a single geographical location in Korea was conducted by indirect fluorescent antibody assay (IFA). Considering an antibody titer of ≥1:128 as positive reaction, 15.2% of total sera were positive. In males and females older than 40 years old, levels of IgM and IgG were 1.2% and 14%, respectively. The sera with antibody titers of ≥1:128 to Legionella species accounted for 85 sera, and 9 sera of these were reacted to more than one Legionella species. Reactivity to L. bozemanii, L. micdadei, L. longbeachae, L. pneumophila sg 6, and L. gormanii were 32.9%, 20%, 15%, 10.6%, and 8%, respectively. However, L. pneumophila sg 1, sg 2, and sg 3 did not react to any sera. Serological analysis revealed that the level of antibody in response to L. bozemanii was more prevalent than L. pneumophila. Our results suggest that the antibodies of non-L. pneumophila species, such as L. bozemanii, may be highly prevalent in healthy population within Korea. Although conclusions based on the findings of this study must be cautiously considered given that the population sampled were sourced from a single province, we have added to the knowledge base of serodiagnosis of infections due to non-L. pneumophila species in Korea.

Research Support, Non-U.S. Gov'ts

Affinity Maturation of an Anti-Hepatitis B Virus PreS1 Humanized Antibody by Phage Display: Gi-Hyeok Yang , Sun Ok Yoon , Myung Hee Jang , Hyo Jeong Hong; J. Microbiol. 2007;45(6):528-533.; DOI: https://doi.org/2640 [pii]

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Abstract: In a previous study we generated an anti-Hepatitis B Virus (HBV) preS1 humanized antibody (HzKR127) that showed in vivo HBV-neutralizing activity in chimpanzees. However, the antigen-binding affinity of the humanized antibody may not be sufficient for clinical use and thus affinity maturation is required for better therapeutic efficacy. In this study, phage display technique was employed to increase the affinity of HzKR127. All six amino acid residues (Glu95-Tyr96-Asp97-Glu98-Ala99-Tyr100) in the heavy (H) chain complementarydetermining region 3 (HCDR3) of HzKR127 were randomized and phage-displayed single chain Fv (scFv) library was constructed. After three rounds of panning, 12 different clones exhibiting higher antigen-binding activity than the wild type ScFv were selected and their antigen-binding specificity for the preS1 confirmed. Subsequently, five ScFv clones were converted to whole IgG and subjected to affinity determination. The results showed that two clones (B3 and A19) exhibited an approximately 6 fold higher affinities than that of HzKR127. The affinity-matured humanized antibodies may be useful in anti-HBV immunotherapy.

Generation and Characterization of a Monoclonal Antibody with Specificity for Mycoplasma arginini: Yeon Sung Son , Hyo Jeong Hong; J. Microbiol. 2007;45(6):547-552.; DOI: https://doi.org/2610 [pii]

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Abstract: Previously, we generated monoclonal antibodies (MAbs) that bound to the surface of human embryonic stem cells (hESCs) in an attempt to discover new hESC-specific surface markers. In this study, MAb 47-235 (IgG1, κ) was selected for further characterization. The MAb bound to the surface of undifferentiated hESCs but did not bind to mouse ESCs or mouse embryonic fibroblast cells in flow cytometric analysis. The antibody immunoprecipitated a 47 kDa protein from the lysates of cell surface-biotinylated hESCs. Identification of the protein by quadrupole time of flight tandem mass spectrometry revealed that 47-235 binds to Ag 243-5 protein of Mycoplasma arginini. BM-Cyclin treatment of the hESCs that reacted with 47-235 resulted in loss of mycoplasma DNA and the reactivity to 47-235. Nevertheless, the hESCs that were reactive to 47-235 maintained self-renewal and pluripotency and thus could be differentiated into three embryonic germ layers.

Guided Selection of Human Antibody Light Chains against TAG-72 Using a Phage Display Chain Shuffling Approach: Sang Jick Kim , Hyo Jeong Hong; J. Microbiol. 2007;45(6):572-577.; DOI: https://doi.org/2606 [pii]

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Abstract: To enhance therapeutic potential of murine monoclonal antibody, humanization by CDR grafting is usually used to reduce immunogenic mouse residues. Most humanized antibodies still have mouse residues critical for antigen binding, but the mouse residues may evoke immune responses in humans. Previously, we constructed a new humanized version (AKA) of mouse CC49 antibody specific for tumor-associated glycoprotein, TAG-72. In this study, to select a completely human antibody light chain against TAG-72, guided selection strategy using phage display was used. The heavy chain variable region (VH) of AKA was used to guide the selection of a human TAG-72-specific light chain variable region (VL) from a human VL repertoire constructed from human PBL. Most of the selected VLs were identified to be originated from the members of the human germline VK1 family, whereas the VL of AKA is more homologous to the VK4 family. Competition binding assay of the selected Fabs with mouse CC49 suggested that the epitopes of the Fabs overlap with that of CC49. In addition, they showed better antigen-binding affinity compared to parental AKA. The selected human VLs may be used to guide the selection of human VHs to get completely human anti-TAG72 antibody.

Expression and Purification of a Recombinant scFv towards the Exotoxin of the Pathogen, Burkholderia pseudomallei: Kue-Peng Lim , HongBin Li , Sheila Nathan; J. Microbiol. 2004;42(2):126-132.; DOI: https://doi.org/2034 [pii]

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Abstract: A single chain variable fragment (scFv) specific towards B. pseudomallei exotoxin had previously been generated from an existing hybridoma cell line (6E6AF83B) and cloned into the phage display vector pComb3H. In this study, the scFv was subcloned into the pComb3X vector to facilitate the detection and purification of expressed antibodies. Detection was facilitated by the presence of a hemagglutinin (HA) tag, and purification was facilitated by the presence of a histidine tag. The culture was grown at 30^oC until log phase was achieved and then induced with 1 mM IPTG in the absence of any additional carbon source. Induction was continued at 30^oC for five h. The scFv was discerned by dual processes-direct enzyme-linked immunosorbent assays (ELISA), and Western blotting. When compared to E. coli strains ER2537 and HB2151, scFv expression was observed to be highest in the E. coli strain Top10F'. The expressed scFv protein was purified via nickel-mediated affinity chromatography and results indicated that two proteins a 52 kDa protein, and a 30 kDa protein were co-purified. These antibodies, when blotted against immobilized exotoxin, exhibited significant specificity towards the exotoxin, compared to other B. pseudomallei antigens. Thus, these antibodies should serve as suitable reagents for future affinity purification of the exotoxin.

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