Journal of Microbiology

Journal Article

The periplasmic chaperone protein Psg_2795 contributes to the virulence of Pseudomonas savastanoi pv. glycinea: the causal agent of bacterial blight of soybean: Xiuhua Wang , Xiaoyan Zhang , Bao-Hui Lu , Jie Gao; J. Microbiol. 2022;60(5):478-487. Published online March 4, 2022; DOI: https://doi.org/10.1007/s12275-022-1469-5

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Abstract: Pseudomonas savastanoi pv. glycinea (Psg, also named P. syringae pv. glycinea and P. amygdali pv. glycinea) is the causative agent of bacterial blight in soybean. The identification of virulence factors is essential for understanding the pathogenesis of Psg. In this study, a mini-Tn5 transposon mutant library of Psg strain PsgNC12 was screened on soybean, and one low-virulent mini-Tn5 mutant, designated as 4573, was identified. Sequence analysis of the 4573-mutant revealed that the mini-Tn5 transposon was inserted in the Psg_2795 gene. Psg_2795 encodes a FimC-domain protein that is highly conserved in Pseudomonas. Further analysis revealed that the mutation and knockout of Psg_2795 results in a reduced virulence phenotype on soybean, decreased motility, weakened bacterial attachment to a glass surface and delayed the population growth within soybean leaves. The phenotype of the 4573-mutant could be complemented nearly to wild-type levels using an intact Psg_2795 gene. Collectively, our results demonstrate that Psg_2795 plays an important role in the virulence, motility, attachment and the population growth of PsgNC12 in soybean. This finding provides a new insight into the function of periplasmic chaperone proteins in a type I pilus and provides reference information for identifying Psg_2795 homologues in P. savastanoi and other bacteria.

Review

Middle East Respiratory Syndrome coronavirus vaccine development: updating clinical studies using platform technologies: Jung-ah Choi , Jae-Ouk Kim; J. Microbiol. 2022;60(3):238-246. Published online January 28, 2022; DOI: https://doi.org/10.1007/s12275-022-1547-8

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Abstract: Middle East Respiratory Syndrome coronavirus (MERS-CoV), a contagious zoonotic virus, causes severe respiratory infection with a case fatality rate of approximately 35% in humans. Intermittent sporadic cases in communities and healthcare facility outbreaks have continued to occur since its first identification in 2012. The World Health Organization has declared MERS-CoV a priority pathogen for worldwide research and vaccine development due to its epidemic potential and the insufficient countermeasures available. The Coalition for Epidemic Preparedness Innovations is supporting vaccine development against emerging diseases, including MERS-CoV, based on platform technologies using DNA, mRNA, viral vector, and protein subunit vaccines. In this paper, we review the usefulness and structure of a spike glycoprotein as a MERSCoV vaccine candidate molecule, and provide an update on the status of MERS-CoV vaccine development. Vaccine candidates based on both DNA and viral vectors coding MERSCoV spike gene have completed early phase clinical trials. A harmonized approach is required to assess the immunogenicity of various candidate vaccine platforms. Platform technologies accelerated COVID-19 vaccine development and can also be applied to developing vaccines against other emerging viral diseases.

Journal Article

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'ts

Therapeutic potential of an AcHERV-HPV L1 DNA vaccine: Hee-Jung Lee , Jong Kwang Yoon , Yoonki Heo , Hansam Cho , Yeondong Cho , Yongdae Gwon , Kang Chang Kim , Jiwon Choi , Jae Sung Lee , Yu-Kyoung Oh , Young Bong Kim; J. Microbiol. 2015;53(6):415-420. Published online May 30, 2015; DOI: https://doi.org/10.1007/s12275-015-5150-0

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8 Citations

Abstract: Cervical cancer is strongly associated with chronic human papillomavirus infections, among which HPV16 is the most common. Two commercial HPV vaccines, Gardasil and Cervarix are effective for preventing HPV infection, but cannot be used to treat existing HPV infections. Previously, we developed a human endogenous retrovirus (HERV)-enveloped recombinant baculovirus capable of delivering the L1 genes of HPV types 16, 18, and 58 (AcHERV-HP16/18/58L1, AcHERV-HPV). Intramuscular administration of AcHERVHPV vaccines induced a strong cellular immune response as well as a humoral immune response. In this study, to examine the therapeutic effect of AcHERV-HPV in a mouse model, we established an HPV16 L1 expressing tumor cell line. Compared to Cervarix, immunization with AcHERVHPV greatly enhanced HPV16 L1-specific cytotoxic T lymphocytes (CTL) in C57BL/6 mice. Although vaccination could not remove preexisting tumors, strong CTL activity retarded the growth of inoculated tumor cells. These results indicate that AcHERV-HPV could serve as a potential therapeutic DNA vaccine against concurrent infection with HPV 16, 18, and 58.

Prevalence of Human Papillomavirus Infection and Genotype Distribution Determined by the Cyclic-Catcher Melting Temperature Analysis in Korean Medical Checkup Population: Yun-Jee Kim , Min-Jung Kwon , Hee-Yeon Woo , Soon-Young Paik; J. Microbiol. 2013;51(5):665-670. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3160-3

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Abstract: Although cytology screening has reduced the incidence and mortality rate of cervical cancer significantly, its usefulness is limited to samples from the site of the lesion, resulting in its low sensitivity and unsuitability for use in medical checkups. The purpose of the present study was to evaluate the prevalence of HPV infection using genotype distribution and to analyze the correlation of the HPV DNA test results with cytological results. We also evaluated the benefits of quantitative information obtained from cyclic-catcher melting temperature analysis (CMTA) in screening for cervical cancer. We performed cyclic-CMTA using AnyplexTM II HPV28 Detection in combination with cervical cytology for 2,181 subjects. The following HPV positivity types were detected using cyclic-CMTA and HPV positivity was found to increase together with the severity of the cytology results: (1) For 419 HPV positive specimens, HPV DNA was detected in 18.1% of normal specimens, 78.3% of ASCUS, and all of LSIL and HSIL; (2) high-risk HPV DNAs were detected in 63.3% of normal (N=547), 65.9% of ASCUS (N=41), 76.9% of LSIL (N=13), and 88.9% of HSIL (N=9) among total detected HPV DNA regardless multiple detection; (3) multiple HPV genotypes were detected in 4.8% of normal specimens (N=2,146), 52.2% of ASCUS (N=23), 57.1% of LSIL (N=7), and 40.0% of HSIL (N=5). In addition, a high level of viral DNA was observed using cyclic-CMTA in all specimens beyond the LSIL stage according to cytology, while only 6% of specimens with normal cytology showed a correlation with viral quantitation by cyclic-CMTA. The combination of HPV genotyping with a quantitative assay and cytology will allow for a more accurate diagnosis of cervical cancer.

The Production and Immunogenicity of Human Papillomavirus Type 58 Virus-like Particles Produced in Saccharomyces cerevisiae: Hye-Lim Kwag , Hyoung Jin Kim , Don Yong Chang , Hong-Jin Kim; J. Microbiol. 2012;50(5):813-820. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2292-1

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15 Citations

Abstract: Human papillomavirus (HPV) is the cause of most cases of cervical cancer. HPV type 58 (HPV58) is the second most frequent cause of cervical cancer and high-grade squamous intraepithelial lesions (HSIL) in Asia and South / Central America, respectively. However, there is no vaccine against HPV58, although there are commercially available vaccines against HPV16 and 18. In this study, we produced HPV58 L1 protein from Saccharomyces cerevisiae, and investigated its immunogenicity. We first determined the optimum period of culture for obtaining HPV58 L1. We found that a considerable portion of the HPV58 L1 resulting from 48 h culture cannot be recovered by purification, while the HPV58 L1 resulting from 144 h culture is recovered efficiently: the yield of HPV58 L1 finally recovered from 144 h culture was 2.3 times higher than that from 48 h culture, although the production level of L1 protein from 144 h culture was lower than that from 48 h culture. These results indicate that the proportion of functional L1 protein from 144 h-cultured cells is significantly higher than that of 48 h-cultured cells. The HPV58 L1 purified from the 144 h culture was correctly assembled into structures similar to naturally occurring HPV virions. Immunization with the HPV58 L1 efficiently elicited anti-HPV58 neutralizing antibodies and antigen-specific CD4+ and CD8+ T cell proliferations, without the need for adjuvant. Our findings provide a convenient method for obtaining substantial amounts of highly immunogenic HPV58 L1 from S. cerevisiae.

Enhancement of Immunotherapeutic Effects of HPV16E7 on Cervical Cancer by Fusion with CTLA4 Extracellular Region: Yi Zheng , Yijuan Zhang , Jun Wan , Chaofan Shi , Laiqiang Huang; J. Microbiol. 2008;46(6):728-736. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0087-1

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17 Citations

Abstract: Cervical cancer is caused by infection by high-risk human papillomavirus (HPV), especially HPV16. Limitations in current treatments of cervical cancers call for the development of new and improved immunotherapies. This study aims at investigating the efficacy of a novel vaccine consisting of modified HPV 16E7 fused with human cytotoxic T-lymphocyte antigen 4 (CTLA4). The regions in HPV16 E7 gene associated with its transformation and CTL-enhanced response were modified; the resultant HPV16mE7 was fused with extracellular region of CTLA4 to generate HPVm16E7-eCTLA4 fusion protein. Binding of this fusion protein to B7 molecules expressed on antigen presenting-cells (APCs) was demonstrated. C57BL/6 (H-2b) mice immunized with low dose of the fusion protein (10 μg) produced higher titer antibody and stronger specific CTL response, and expressed higher levels of IFN-γ and IL-12, compared with those immunized with HPVm16E7 only or admixture of HPVm16E7 and CTLA4, or PBS; and were protected from lethal dose tumor challenge. Tumor growth was retarded and survival prolonged in mouse models with the fusion protein treatment. Our results demonstrate that fusion of HPV16 E7 with eCTLA4 targeting APCs resulted in enhanced immunity, and that this fusion protein may be useful for improving the efficacy of immunotherapeutic treatments of cervical cancer and other HPV16 infection-associated tumors.

Review

Strategies Against Human Papillomavirus Infection and Cervical Cancer: Woon-Won Jung , Taehoon Chun , Donggeun Sul , Kwang Woo Hwang , Hyung-Sik Kang , Duck Joo Lee , In-Kwon Han; J. Microbiol. 2004;42(4):255-266.; DOI: https://doi.org/2112 [pii]

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Abstract: Papillomaviruses infect a wide variety of animals, including humans. The human papillomavirus (HPV), in particular, is one of the most common causes of sexually transmitted disease. More than 200 types of HPV have been identified by DNA sequence data, and 85 HPV genotypes have been well characterized to date. HPV can infect the basal epithelial cells of the skin or inner tissue linings, and are, accordingly, categorized as either cutaneous or mucosal type. HPV is associated with a panoply of clinical conditions, ranging from innocuous lesions to cervical cancer. In the early 1980s, studies first reported a link between cervical cancer and genital HPV infection. Genital HPV infections are now recognized to be a major risk factor in at least 95% of cervical cancers. 30 different HPV genotypes have been identified as causative of sexually transmitted diseases, most of which induce lesions in the cervix, vagina, vulva, penis, and anus, as the result of sexual contact. There is also direct evidence demonstrating that at least four of these genotypes are prerequisite factors in cervical cancer. The main aim of this review was to evaluate the current literature regarding the pathovirology, diagnostics, vaccines, therapy, risk groups, and further therapeutic directions for HPV infections. In addition, we reviewed the current status of HPV infections in South Korean women, as evidenced by our data.

Retraction of Publication

Retraction Note to: Cryptic prophages in a blaNDM‑1‑bearing plasmid increase bacterial survival against high NaCl concentration, high and low temperatures, and oxidative and immunological stressors: So Yeon Kim , Kwan Soo Ko; J. Microbiol. 2023;61(4):481-481.; DOI: https://doi.org/10.1007/s12275-023-00049-1

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Abstract: Retraction Note to: Journal of Microbiology (2020) Vol. 58, No. 6, pp. 483–488 https://doi.org/10.1007/s12275-020-9605-6 The Editor-in-Chief has retracted this article at the request of the authors. After publication concerns were raised that prophage sequences do not exist in the genome of the plasmid pNDM-A1 used in this study. The authors have not been able to confirm the existence of prophage sequences in the plasmid. As a result, the Editor-in-Chief no longer has confidence in the results and conclusions presented in this article. Kwan Soo Ko agrees with this retraction. So Yeon Kim has not responded to correspondence from the Editor-in-Chief about this retraction.

Production and Prophylactic Efficacy Study of Human Papillomavirus-like Particle Expressing HPV16 L1 Capsid Protein: Jie-Yun Park , Hyun-Mi Pyo , Sun-Woo Yoon , Sun-Young Baek , Sue-Nie Park , Chul-Joong Kim , Haryoung Poo; J. Microbiol. 2002;40(4):313-318.

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Abstract: To perform the prophylactic study of a vaccine derived from human papillomavirus (HPV) using Balb/c mice, we produced virus like particles consisting of HPV capsid protein L1 which has been reported to induce significant humoral and cellular immunity using various animal model systems. In order to produce HPV16 VLPs, the cDNA of L1 capsid protein in HPV type 16, obtained by polymerase chain reaction, was inserted into yeast expression vector, YEG[alpha]-HIR525 under the control of GAL10 promoter. The transformation of YEG[alpha]-HPV16 L1 was performed into the yeast Saccharomyces cerevisiae Y2805 by the lithium acetate method and the yeast clone expressing the highest level of L1 capsid protein of human papillomavirus type 16 was selected by Western blot analysis using anti-HPV16 L1 antibody. The purification of HPV16 VLP has been performed by the ultracentrifugation and gel-filtration methods. To validate the vaccine efficacy of the purified HPV16 VLPs and investigate the properties of HPV16 VLPs to induce humoral immunity, ELISA assay was performed. A significantly increased production of anti-HPV16 VLP antibodies was observed in sera from immunized mice. The neutralization activity of antibodies in the sera from the vaccinated mice was demonstrated by a rapid and simple assay to detect hemagglutihation inhibition activity

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