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Park J, Zhang Z, Belinskaya T, Tsoras AN, Chao CC, Jiang L, Champion JA. Dual-Antigen Subunit Vaccine Nanoparticles for Scrub Typhus. Pathogens 2023; 12:1390. [PMID: 38133275 PMCID: PMC10745692 DOI: 10.3390/pathogens12121390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Orientia tsutsugamushi is the causative pathogen of scrub typhus, an acute febrile disease prevalent in the Asia-Pacific region that is spread to people through chigger bites. Despite the emerging threat, there is no currently available vaccine against O. tsutsugamushi. Here, we developed dual-antigen subunit vaccine nanoparticles using recombinant 47 kD and 56 kD proteins, which are immunogenic outer membrane antigens of O. tsutsugamushi. The biocompatible protein vaccine nanoparticles were formed via desolvation of r56 or r47E antigens with acetone, coating with an additional layer of the 56 kD protein, and stabilization with reducible homobifunctional DTSSP and heterobifunctional SDAD crosslinkers. The dual-antigen subunit vaccine nanoparticles significantly improved antigen-specific antibody responses in vaccinated mice. Most importantly, the dual-antigen nanoparticles coated with an additional layer of the 56 kD protein were markedly more immunogenic than soluble antigens or single-antigen nanoparticles in the context of cellular immune responses. Given the significance of cellular immune responses for protection against O. tsutsugamushi, these results demonstrate the potent immunogenicity of dual-layered antigen nanoparticles and their potential as a promising strategy for developing vaccines against scrub typhus.
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Affiliation(s)
- Jaeyoung Park
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Dr. NW, Atlanta, GA 30332, USA; (J.P.); (A.N.T.)
| | - Zhiwen Zhang
- Henry Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Dr, Bethesda, MD 20817, USA; (Z.Z.); (T.B.)
- Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910, USA;
| | - Tatyana Belinskaya
- Henry Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Dr, Bethesda, MD 20817, USA; (Z.Z.); (T.B.)
- Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910, USA;
| | - Alexandra N. Tsoras
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Dr. NW, Atlanta, GA 30332, USA; (J.P.); (A.N.T.)
| | - Chien-Chung Chao
- Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910, USA;
| | - Le Jiang
- Henry Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Dr, Bethesda, MD 20817, USA; (Z.Z.); (T.B.)
- Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910, USA;
| | - Julie A. Champion
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Dr. NW, Atlanta, GA 30332, USA; (J.P.); (A.N.T.)
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2
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Yang SL, Tsai KH, Chen HF, Luo JY, Shu PY. Evaluation of Enzyme-Linked Immunosorbent Assay Using Recombinant 56-kDa Type-Specific Antigens Derived from Multiple Orientia tsutsugamushi Strains for Detection of Scrub Typhus Infection. Am J Trop Med Hyg 2020; 100:532-539. [PMID: 30526730 DOI: 10.4269/ajtmh.18-0391] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Scrub typhus is caused by the intracellular bacterium Orientia tsutsugamushi. The 56-kDa type-specific antigen (TSA) displays a significant antigenic variation across different O. tsutsugamushi strains. To minimize the influence of the antigenic diversity of TSA on assay sensitivity, we developed a mixed-TSA enzyme-linked immunosorbent assay (mixed-TSA ELISA) using a mixture of recombinant TSAs of prototype (Karp, Gilliam, and Kato) and local (TW-1, TW-10, TW-19, and TW-22) O. tsutsugamushi strains as antigens to detect immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against O. tsutsugamushi. These four local strains covered a major part of the total genetic diversity of TSA gene of O. tsutsugamushi in Taiwan. A total of 109 acute-phase serum samples from O. tsutsugamushi polymerase chain reaction-positive, scrub typhus patients, and 82 negative control serum samples from non-scrub typhus cases were used for evaluation of the recombinant TSA-based ELISA. We compared the performance of the mixed-TSA ELISA with immunofluorescence assay (IFA), which is considered the gold standard method for the serological diagnosis of scrub typhus. The results indicated that the sensitivity of IgM mixed-TSA ELISA (80.7%) was significantly higher than that of IgM IFA (68.8%). We demonstrated that the mixed-TSA ELISA had a high sensitivity and specificity and can be used for screening of scrub typhus patient in the early phase of the disease.
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Affiliation(s)
- Su-Lin Yang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Republic of China
| | - Kun-Hsien Tsai
- Department of Public Health and Institute of Environmental Health, College of Public Health, National Taiwan University, Taipei, Republic of China
| | - Hsiang-Fei Chen
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Republic of China
| | - Jun-Yu Luo
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Republic of China
| | - Pei-Yun Shu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Republic of China
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3
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Lalchhandama K. Orientia tsutsugamushi, the agent of scrub typhus. WIKIJOURNAL OF MEDICINE 2019. [DOI: 10.15347/wjm/2019.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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4
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Díaz FE, Abarca K, Kalergis AM. An Update on Host-Pathogen Interplay and Modulation of Immune Responses during Orientia tsutsugamushi Infection. Clin Microbiol Rev 2018; 31:e00076-17. [PMID: 29386235 PMCID: PMC5967693 DOI: 10.1128/cmr.00076-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is the causative agent of scrub typhus in humans, a serious mite-borne disease present in a widespread area of endemicity, which affects an estimated 1 million people every year. This disease may exhibit a broad range of presentations, ranging from asymptomatic to fatal conditions, with the latter being due to disseminated endothelial infection and organ injury. Unique characteristics of the biology and host-pathogen interactions of O. tsutsugamushi, including the high antigenic diversity among strains and the highly variable, short-lived memory responses developed by the host, underlie difficulties faced in the pursuit of an effective vaccine, which is an imperative need. Other factors that have hindered scientific progress relative to the infectious mechanisms of and the immune response triggered by this bacterium in vertebrate hosts include the limited number of mechanistic studies performed on animal models and the lack of genetic tools currently available for this pathogen. However, recent advances in animal model development are promising to improve our understanding of host-pathogen interactions. Here, we comprehensively discuss the recent advances in and future perspectives on host-pathogen interactions and the modulation of immune responses related to this reemerging disease, highlighting the role of animal models.
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Affiliation(s)
- Fabián E Díaz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katia Abarca
- Departamento en Enfermedades Infecciosas e Inmunología Pediátricas, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Luce-Fedrow A, Lehman ML, Kelly DJ, Mullins K, Maina AN, Stewart RL, Ge H, John HS, Jiang J, Richards AL. A Review of Scrub Typhus (Orientia tsutsugamushi and Related Organisms): Then, Now, and Tomorrow. Trop Med Infect Dis 2018; 3:E8. [PMID: 30274407 PMCID: PMC6136631 DOI: 10.3390/tropicalmed3010008] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/26/2022] Open
Abstract
Scrub typhus and the rickettsial diseases represent some of the oldest recognized vector-transmitted diseases, fraught with a rich historical aspect, particularly as applied to military/wartime situations. The vectors of Orientia tsutsugamushi were once thought to be confined to an area designated as the Tsutsugamushi Triangle. However, recent reports of scrub typhus caused by Orientia species other than O. tsutsugamushi well beyond the limits of the Tsutsugamushi Triangle have triggered concerns about the worldwide presence of scrub typhus. It is not known whether the vectors of O. tsutsugamushi will be the same for the new Orientia species, and this should be a consideration during outbreak/surveillance investigations. Additionally, concerns surrounding the antibiotic resistance of O. tsutsugamushi have led to considerations for the amendment of treatment protocols, and the need for enhanced public health awareness in both the civilian and medical professional communities. In this review, we discuss the history, outbreaks, antibiotic resistance, and burgeoning genomic advances associated with one of the world's oldest recognized vector-borne pathogens, O. tsutsugamushi.
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Affiliation(s)
- Alison Luce-Fedrow
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Marcie L Lehman
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Daryl J Kelly
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA.
| | - Kristin Mullins
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Alice N Maina
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Richard L Stewart
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Hong Ge
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Heidi St John
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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Le Viet N, Laroche M, Thi Pham HL, Viet NL, Mediannikov O, Raoult D, Parola P. Use of eschar swabbing for the molecular diagnosis and genotyping of Orientia tsutsugamushi causing scrub typhus in Quang Nam province, Vietnam. PLoS Negl Trop Dis 2017; 11:e0005397. [PMID: 28241043 PMCID: PMC5344524 DOI: 10.1371/journal.pntd.0005397] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 03/09/2017] [Accepted: 02/07/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Scrub typhus is a rickettsiosis which is caused by Orientia tsutsugamushi and occurs throughout the Asia-Pacific region. Molecular diagnosis of rickettsioses using eschar swabs has recently emerged, and may be very useful for the diagnosis of these diseases in tropical settings. METHODOLOGY/PRINCIPAL FINDINGS Quantitative polymerase chain reaction (qPCR) was used to detect O. tsutsugamushi DNA in whole blood and eschar swab specimens of 67 patients who were clinically suspected of scrub typhus in Quang Nam province, Vietnam. Among the 20 patients for whom both eschar and whole blood were obtained, 17 (85%) of the eschar specimens and 5 (25%) of the whole blood specimens tested positive for O. tsutsugamushi. Genetic analysis of the 56-kDa TSA gene sequences demonstrated that the 14 sequences obtained in this study, including 12 eschar swabs and 2 whole blood specimens, were related to 4 groups: Karp, Kawasaki, Gilliam (JG-v and TG-v) and TA716. The majority (9/14; 64.4%) of contemporary O. tsutsugamushi genotypes in Quang Nam province were related to the Karp group. CONCLUSIONS These results suggest that polyclonal antigen pools used for serological testing in the future should contain at least Karp, Kawasaki, Gilliam and TA716 antigens for Vietnamese patients, as well as patients who have traveled to Vietnam. qPCR after eschar swabbing should be considered for molecular diagnosis of scrub typhus in endemic patients as well as in travelers, since it is easy to perform and appears very useful for the rapid detection of Orientia tsutsugamushi in the early phase of infection.
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Affiliation(s)
- Nhiem Le Viet
- URMITE, Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection, Marseille, France
- Department of Tropical Diseases, Quang Nam Central General Hospital, Quang Nam, Vietnam
| | - Maureen Laroche
- URMITE, Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection, Marseille, France
| | - Hoa L. Thi Pham
- Department of Infectious Diseases, University of Medicine and Pharmacy of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Nho L. Viet
- Department of Internal Medicine, Quang Nam Central General Hospital, Quang Nam, Vietnam
| | - Oleg Mediannikov
- URMITE, Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection, Marseille, France
| | - Didier Raoult
- URMITE, Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection, Marseille, France
| | - Philippe Parola
- URMITE, Aix Marseille Université, UM63, CNRS 7278, IRD 198, INSERM 1095, IHU - Méditerranée Infection, Marseille, France
- * E-mail:
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7
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Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is responsible for more than one million cases of scrub typhus annually throughout the Asia-Pacific region. Human infection occurs via the bite of the larval form (chigger) of several species of trombiculid mites. While in some patients the result of infection is a mild, febrile illness, others experience severe complications, which may even be fatal. This review discusses the genome and biology of the causative agent, the changing epidemiology of scrub typhus, the challenges of its diagnosis, and current treatment recommendations.
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Affiliation(s)
- Sunil Thomas
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania USA
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8
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Lee SM, Kwon HY, Im JH, Baek JH, Kang JS, Lee JS. Identification of Outer Membrane Vesicles Derived from Orientia tsutsugamushi. J Korean Med Sci 2015; 30:866-70. [PMID: 26130947 PMCID: PMC4479938 DOI: 10.3346/jkms.2015.30.7.866] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 04/01/2015] [Indexed: 11/23/2022] Open
Abstract
Orientia tsutsugamushi, a causative pathogen of Scrub typhus, is a gram-negative intracellular bacterium. Outer membrane vesicles (OMVs) are produced from the membrane of bacteria and play many roles related to the survival of the pathogen. However, there have been no reports confirming whether O. tsutsugamushi indeed produce OMVs. O. tsutsugamushi boryong was cultured in ECV-304 cells for the purification of OMVs. Western blot analysis and immunoenrichment using anti-O. tsutsugamushi monoclonal antibody and electron microscopy were employed for identification and characterization of OMVs. We confirm the presence of OMVs derived from O. tsutsugamushi, and also found that those OMVs contain a major surface antigen of 56-kDa protein and variant immunogenic antigens.
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Affiliation(s)
- Sun-Myoung Lee
- Translation Research Center, Inha University School of Medicine, Incheon, Korea
| | - Hea Yoon Kwon
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae-Hyong Im
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Ji Hyeon Baek
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University School of Medicine, Incheon, Korea
| | - Jin-Soo Lee
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
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9
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Involvement of lipid rafts in the budding-like exit of Orientia tsutsugamushi. Microb Pathog 2013; 63:37-43. [DOI: 10.1016/j.micpath.2013.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/05/2013] [Indexed: 01/20/2023]
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10
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Chao CC, Huber ES, Porter TB, Zhang Z, Ching WM. Analysis of the cross-reactivity of various 56 kDa recombinant protein antigens with serum samples collected after Orientia tsutsugamushi infection by ELISA. Am J Trop Med Hyg 2011; 84:967-72. [PMID: 21633035 DOI: 10.4269/ajtmh.2011.10-0545] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Orientia tsutsugamushi, the etiologic agent of scrub typhus, has a highly expressed and immunodominant 56-kD outer membrane protein. This protein is one of the leading candidates for diagnosis and vaccine development for scrub typhus. Previous studies using recombinant 56-kD protein (r56s) derived from Karp strain (Kpr56) in a mouse model have shown good homologous protection but only moderate to poor heterologous protection. We evaluated the cross-reactivity of recombinant 56-kD proteins from Karp, Kato, Gilliam, TA763, and three chimeric 56-kD proteins. Not all r56s are equally reactive with strain-specific serum samples. These data provide a first glance of how reactive these r56s are toward the antiserum of different strains and which r56 exhibits the broadest reactivity. A formulation of this combination has the potential to provide broad protection against the heterologous challenge and to be used in a highly sensitive diagnostic assay.
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Affiliation(s)
- Chien-Chung Chao
- Viral and Rickettsial Diseases Department, Infectious Diseases Directorate, Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910, USA.
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Wongprompitak P, Anukool W, Wongsawat E, Silpasakorn S, Duong V, Buchy P, Morand S, Frutos R, Ekpo P, Suputtamongkol Y. Broad-coverage molecular epidemiology of Orientia tsutsugamushi in Thailand. INFECTION GENETICS AND EVOLUTION 2011; 15:53-8. [PMID: 21712103 DOI: 10.1016/j.meegid.2011.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 06/01/2011] [Accepted: 06/13/2011] [Indexed: 11/18/2022]
Abstract
Orientia tsutsugamushi, an obligate intracellular bacterium closely related to the genus Rickettsia, is the causative agent of scrub typhus, a major cause of febrile illness in rural areas of Asia-Pacific region. Scrub typhus is transmitted by the bite of infected mites of the genus Leptotrombidium. The region of the 56-kDa TSA gene spanning from variable domain I (VDI) to variable domain IV (VDIV) was sequenced and used for genotyping 77 O. tsutsugamushi samples from human patients confirmed with scrub typhus from 2001 to 2003 and 2009 to 2010 in different regions of Thailand. These sequences were also compared to previously published 56-kDa TSA sequences. Only 4 genotypes out of 8 previously reported in Thailand were identified, i.e. Karp, JG-v, TA763 and Kato, respectively. Two strains were not associated with known genotypes but were closely related to Taiwanese strains. The Karp genotype was confirmed as the predominant clade. The JG-v and TA763 genotypes, in contrast to other studies, also were found. The genotype TA716 was not found, except for one strain previously described.
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Affiliation(s)
- Patimaporn Wongprompitak
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
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Kinetics and magnitude of antibody responses against the conserved 47-kilodalton antigen and the variable 56-kilodalton antigen in scrub typhus patients. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:1021-7. [PMID: 21508168 DOI: 10.1128/cvi.00017-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Western blot analysis of Orientia tsutsugamushi whole-cell lysates with scrub typhus patient sera has identified at least five protein antigens of O. tsutsugamushi with molecular sizes of 22 kDa, 47 kDa, 56 kDa, 58 kDa, and 110 kDa. In this study, sera from serial bleedings of 108 patients were used to study the kinetics and the magnitude of specific antibody responses against the 47-kDa and 56-kDa antigens. Recombinant protein of the conserved 47-kDa antigen (r47b) or a mixture of truncated 56-kDa antigen (r56s) from three prototype strains was used as the antigen in an enzyme-linked immunosorbent assay (ELISA). Our results showed that 76% and 93% of these patients had elevated IgM and IgG against r47b, respectively, and 98% and 100% had elevated IgM and IgG against r56s, respectively. The kinetics of antibody responses against r47b and r56s can be grouped into three patterns. In the first type of response, IgM and IgG against r47b and r56s appeared about the same time. The IgM and IgG titers against r56s were much higher than those against r47b. In the second type of response, induction of IgM appeared to be similar to that in the first type. The major difference to the first type is that the IgG titers against r47b were induced at least 1 week later than those against the r56s. The third type showed strong IgG responses against both r47b and r56s, and low or no IgM responses indicated a secondary infection. This is the first systematic investigation of antibody response kinetics against the conserved 47-kDa antigen versus the variable 56-kDa antigen in scrub typhus patients.
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Rodkvamtook W, Ruang-Areerate T, Gaywee J, Richards AL, Jeamwattanalert P, Bodhidatta D, Sangjun N, Prasartvit A, Jatisatienr A, Jatisatienr C. Isolation and characterization of Orientia tsutsugamushi from rodents captured following a scrub typhus outbreak at a military training base, Bothong district, Chonburi province, central Thailand. Am J Trop Med Hyg 2011; 84:599-607. [PMID: 21460017 PMCID: PMC3062456 DOI: 10.4269/ajtmh.2011.09-0768] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 10/14/2010] [Indexed: 11/07/2022] Open
Abstract
Orientia tsutsugamushi, an obligate intracellular Gram-negative bacterium, is the causative agent of scrub typhus, a vector-borne disease transmitted by infected chiggers (trombiculid mite larvae). In 2002, an outbreak of scrub typhus occurred among Royal Thai Army troops during the annual field training at a military base in Bothong district, Chonburi province, central Thailand. This report describes the outbreak investigation including its transmission cycle. Results showed that 33.9% of 174 trained troops had scrub typhus-like signs and symptoms and 9.8% of those were positive for O. tsutsugamushi-specific antibodies by indirect fluorescence antibody assay. One hundred thirty-five rodents were captured from this training area, 43% of them had antibodies against O. tsutsugamushi. Six new O. tsutsugamushi isolates were obtained from captured rodent tissues and successfully established in cell culture. Phylogenetic studies showed that these six isolates were either unique or related to a native genotype of previously described isolates from Thailand.
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Affiliation(s)
- Wuttikon Rodkvamtook
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
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14
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Duong V, Mai TTX, Blasdell K, Lo LV, Morvan C, Lay S, Anukool W, Wongprompitak P, Suputtamongkol Y, Laurent D, Richner B, Ra C, Chien BT, Frutos R, Buchy P. Molecular epidemiology of Orientia tsutsugamushi in Cambodia and Central Vietnam reveals a broad region-wide genetic diversity. INFECTION GENETICS AND EVOLUTION 2011; 15:35-42. [PMID: 21241829 DOI: 10.1016/j.meegid.2011.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 12/23/2010] [Accepted: 01/04/2011] [Indexed: 11/27/2022]
Abstract
Scrub typhus is an acute infectious disease caused by an obligate intracellular bacterium Orientia tsutsugamushi following the bite of infected trombiculid mites of the genus Leptotrombidium. This zoonotic disease is a major cause of febrile illness in the Asia-Pacific region, with a large spectrum of clinical manifestations from unapparent or mild disease to fatal disease. O. tsutsugamushi is characterized by a very high genomic plasticity and a large number of antigenic variants amongst strains. The 56-kDa type specific antigen (TSA) gene, encoding the major antigenic protein, was used as reference to investigate the genetic relationships between the strains and to genotype O. tsutsugamushi isolates. The open reading frame of the 56-kDa TSA gene of 41 sequences (28 Cambodian and 13 Vietnamese strains) from patient samples were sequenced and used for genotyping. The 28 Cambodian isolates clustered into 5 major groups, including Karp (43.5%), JG-v (25%), Kato/TA716 (21.5%), TA763 (3.5%) and Gilliam (3.5%). Karp (77%), TA763 (15.5%) and JG-v (7.5%) strains were identified amongst the 13 Vietnamese isolates. This is the first countrywide genotyping description in Cambodia and in Central Vietnam. These results demonstrate the considerable diversity of genotypes in co-circulation in both countries. The genotyping result might raise awareness amongst Cambodian and Vietnamese clinicians of the high genetic diversity of circulating O. tsutsugamushi strains and provides unique and beneficial data for serological and molecular diagnosis of scrub typhus infections as well as raw materials for future studies and vaccine development.
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Affiliation(s)
- Veasna Duong
- Institut Pasteur in Cambodia, Virology Unit, 5 Monivong Blvd., Phnom Penh, Cambodia
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15
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Lu HY, Tsai KH, Yu SK, Cheng CH, Yang JS, Su CL, Hu HC, Wang HC, Huang JH, Shu PY. Phylogenetic analysis of 56-kDa type-specific antigen gene of Orientia tsutsugamushi isolates in Taiwan. Am J Trop Med Hyg 2010; 83:658-63. [PMID: 20810835 DOI: 10.4269/ajtmh.2010.09-0608] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Scrub typhus is a rickettsial disease transmitted to humans through the bite of chigger mites infected with Orientia tsutsugamushi, and is an endemic disease in Taiwan. To elucidate the molecular epidemiology of O. tsutsugamushi, the complete open reading frame of the 56-kDa type-specific antigen gene sequence of strains isolated from scrub typhus patients were determined and analyzed. A total of 116 isolates of O. tsutsugamushi were successfully isolated from patients infected in diverse geographic origins including Taiwan and three offshore islets, Kinmen, Matsu, and Penghu between May 2006 and December 2007. Sequence analysis revealed that 22 distinct sequence types could be identified that were broadly distributed in different clusters of the phylogenetic tree. Most of the isolates belong to Karp, Kawasaki, and Kuroki genotypes and are closely related to strains from Thailand, Japan, and Korea, whereas unique isolates different from other countries were also found in Taiwan. Distinct seasonal distributions were found in different sequence types. Some sequence types caused disease in the cold season, whereas others caused disease in the warm season.
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Affiliation(s)
- Hsiu-Ying Lu
- Research and Diagnostic Center, Centers for Disease Control, Department of Health, Taipei, Taiwan, Republic of China.
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17
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Genome-based construction of the metabolic pathways of Orientia tsutsugamushi and comparative analysis within the Rickettsiales order. Comp Funct Genomics 2010:623145. [PMID: 18528528 PMCID: PMC2408715 DOI: 10.1155/2008/623145] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 01/29/2008] [Accepted: 03/04/2008] [Indexed: 11/18/2022] Open
Abstract
Orientia tsutsugamushi, the causative agent of
scrub typhus, is an obligate intracellular
bacterium that belongs to the order of
Rickettsiales. Recently, we have reported that
O. tsutsugamushi has a unique
genomic structure, consisting of highly
repetitive sequences, and suggested that it may
provide valuable insight into the evolution of
intracellular bacteria. Here, we have used
genomic information to construct the major
metabolic pathways of
O. tsutsugamushi and performed a
comparative analysis of the metabolic genes and
pathways of O. tsutsugamushi
with other members of the Rickettsiales order.
While O. tsutsugamushi has the
largest genome among the members of this order,
mainly due to the presence of repeated
sequences, its metabolic pathways have been
highly streamlined. Overall, the metabolic
pathways of O. tsutsugamushi
were similar to Rickettsia but
there were notable differences in several
pathways including carbohydrate metabolism, the
TCA cycle, and the synthesis of cell wall
components as well as in the transport systems.
Our results will provide a useful guide to the
postgenomic analysis of
O. tsutsugamushi and lead
to a better understanding of the virulence and
physiology of this intracellular pathogen.
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Cho KA, Jun YH, Suh JW, Kang JS, Choi HJ, Woo SY. Orientia tsutsugamushi induced endothelial cell activation via the NOD1-IL-32 pathway. Microb Pathog 2010; 49:95-104. [PMID: 20470879 DOI: 10.1016/j.micpath.2010.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/27/2010] [Accepted: 05/04/2010] [Indexed: 01/23/2023]
Abstract
Orientia tsutsugamushi (OT), the causative agent of scrub typhus, is an obligate intracellular bacterium. In order to verify the inflammatory responses involved in the pathogenesis of scrub typhus, we assessed the cytokine profile of the human endothelial cell line, ECV304, after OT infection. We noted that CCL5, CCL17, IL-1alpha, IL-6, IL-8, IL-10, IL-15, TNF-alpha and TNF-beta were strongly induced in response to OT. Additionally, IL-32, the candidate modulator for the induction of IL-6 and IL-8, was increased significantly with OT infection and these increases coincided with NOD1 pathway activation. Thus, we hypothesized that NOD1 pathway and IL-32 might act on cytokine release in endothelial cells as a modulator of the inflammation caused by OT infection. NOD1 siRNA resulted in a reduction in IL-32 levels, and also reduced IL-1beta, IL-6, IL-8, and ICAM-1 expression in OT-infected ECV304 cells. These changes in IL-1beta, IL-6, IL-8, and ICAM-1 induced by NOD1 knockdown were reversed as the result of IL-32 treatment. This indicated that OT infection activated the NOD1 pathway followed by IL-32 secretion, thus resulting in the production and expression of IL-1beta, IL-6, IL-8, and ICAM-1. Therefore, IL-32 might perform a role upstream of the inflammatory reaction in endothelial cells of OT infection.
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Affiliation(s)
- Kyung-Ah Cho
- Department of Microbiology, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
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19
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Park S, Hwang KJ, Chu H, Park SH, Shim SK, Choi YS, Kim JS, Park MY. Inhibition of Orientia tsutsugamushi infection by a truncated recombinant 56-kDa outer membrane protein. Lett Appl Microbiol 2010; 50:445-51. [PMID: 20302599 DOI: 10.1111/j.1472-765x.2010.02814.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi. METHODS AND RESULTS The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion assay. The results showed that the 56-kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56-kDa 1-418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay. CONCLUSIONS The truncated 56-kDa protein (a.a. 1-418) plays an important role in O. tsutsugamushi infection, and the 56-kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection. SIGNIFICANCE AND IMPACT OF THE STUDY The attachment of the 56-kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56-kDa protein.
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Affiliation(s)
- S Park
- Division of Zoonoses, Center for Immunology and Pathology, National Institute of Health, Seoul, Korea
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20
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Lee JH, Cho NH, Kim SY, Bang SY, Chu H, Choi MS, Kim IS. Fibronectin facilitates the invasion of Orientia tsutsugamushi into host cells through interaction with a 56-kDa type-specific antigen. J Infect Dis 2008; 198:250-7. [PMID: 18500929 DOI: 10.1086/589284] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium. The pathogen's mechanism of cellular invasion is poorly characterized. METHODS Through ligand immunoblots, glutathione S-transferase (GST) pull-down assays, and in vitro inhibition assays of intracellular invasion, a bacterial ligand was identified and was shown to interact with fibronectin (Fn) to enhance the intracellular invasion of O. tsutsugamushi. RESULTS O. tsutsugamushi can bind to immobilized Fn in vitro, and exogenous Fn stimulates bacterial invasion of mammalian host cells. Bacterial invasion in the presence of Fn was abrogated by the addition of Arg-Gly-Asp peptides or by an anti-alpha5beta1 integrin antibody. Through a ligand immunoblot and GST pull-down assay, a 56-kDa type-specific antigen (TSA56) was identified as the bacterial ligand responsible for the interaction with Fn. Antigenic domain III and the adjacent C-terminal region (aa 243-349) of TSA56 interacted with Fn. Furthermore, we found that the enhanced invasion of the pathogen was abrogated by the addition of purified recombinant peptides derived from TSA56. CONCLUSION Fn facilitates the invasion of O. tsutsugamushi through its interaction with TSA56.
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Affiliation(s)
- Jung-Hee Lee
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
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21
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Tseng BY, Yang HH, Liou JH, Chen LK, Hsu YH. Immunohistochemical study of scrub typhus: a report of two cases. Kaohsiung J Med Sci 2008; 24:92-8. [PMID: 18281226 DOI: 10.1016/s1607-551x(08)70103-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Scrub typhus is a zoonotic disease caused by Orientia tsutsugamushi, which is transmitted by chiggers. The target cells of this rickettsia are poorly defined in humans. Immunohistochemical staining of tissue sections of patients with scrub typhus is helpful in investigating the target cells of this rickettsia in different organs. We studied two autopsy specimens by immunohistochemical staining using a specific antibody against O. tsutsugamushi. Rickettsiae were located in endothelial cells in all of the organs evaluated, namely heart, lung, brain, kidney, appendix and skin, within cardiac muscle cells and renal tubular epithelial cells, and in macrophages located in the lymph node, liver and spleen. In conclusion, O. tsutsugamushi may disseminate into multiple organs through endothelial cells and macrophages, resulting in the development of fatal complications.
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Affiliation(s)
- Bo-Yuan Tseng
- Department of Pathology, Buddhist Tzu Chi General Hospital and University, Hualien, Taiwan
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22
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Blacksell SD, Luksameetanasan R, Kalambaheti T, Aukkanit N, Paris DH, McGready R, Nosten F, Peacock SJ, Day NPJ. Genetic typing of the 56-kDa type-specific antigen gene of contemporary Orientia tsutsugamushi isolates causing human scrub typhus at two sites in north-eastern and western Thailand. ACTA ACUST UNITED AC 2008; 52:335-42. [PMID: 18312580 DOI: 10.1111/j.1574-695x.2007.00375.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in the rural areas of Southeast Asia. Twenty-three strains of O. tsutsugamushi were isolated from patients with scrub typhus in north-east (Udorn Thani province) and western Thailand (Tak province) between 2003 and 2005. The isolates were characterized by sequencing the entire ORF of the 56-kDa-type-specific antigen gene, followed by phylogenetic analysis. The majority (15/23) of isolates clustered with the Karp-type strain, six with a Gilliam-type strain and one each with the TA716- and TA763-type strains. Overall, there was considerable diversity in sequence, comparable to that seen in strains from across the rest of the scrub typhus-endemic world. There was no significant difference in the distributions of strains between the two provinces (P=0.08, Fisher's exact) nor a temporal change in distribution with year of isolation (P=0.80, Fisher's exact). Within this diversity there were also examples of isolates with identical 56-kDa genotypes that were cultured from patients from the same geographical areas.
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Affiliation(s)
- Stuart D Blacksell
- Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.
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23
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Kim MK, Kim MJ, Lee SM, Kang JS. Identification of the Proteinase K-resistant Antigen of Orientia tsutsugamushi by Monoclonal Antibodies. ACTA ACUST UNITED AC 2008. [DOI: 10.4167/jbv.2008.38.1.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mee-Kyung Kim
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Mi-Jeong Kim
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Sun-Myoung Lee
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Jae-Seung Kang
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
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24
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Fournier PE, Siritantikorn S, Rolain JM, Suputtamongkol Y, Hoontrakul S, Charoenwat S, Losuwanaluk K, Parola P, Raoult D. Detection of new genotypes of Orientia tsutsugamushi infecting humans in Thailand. Clin Microbiol Infect 2007; 14:168-73. [PMID: 18076670 DOI: 10.1111/j.1469-0691.2007.01889.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PCR screening of blood specimens taken from 195 patients with serologically confirmed scrub typhus in three Thai provinces detected the 56-kDa protein-encoding gene from Orientia tsutsugamushi in ten (5%) patients. Significant genetic diversity was found among the ten amplicons, with nine new genotypes identified that were different from those found previously in Thailand. Phylogenetically, the ten sequences obtained in the present study and sequences from 71 strains characterised previously were distributed into several clusters that included the Karp, Gilliam, Kuroki, Saitama, Kawasaki and Kato clusters. Two of the new genotypes found in the present study clearly belonged to the Karp cluster. However, the other new genotypes formed three different clusters, including one cluster that appeared to be distant from all previously known clusters, and which may therefore be representative of a previously undescribed serotype. Other genotypes formed two other clusters that may also be associated with undescribed serotypes.
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Affiliation(s)
- P-E Fournier
- Unité des Rickettsies, IFR 48, CNRS UMR6020, Faculté de Médecine, Université de la Méditerranée, Marseille, France
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25
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Tamura A, Ohashi N, Koyama Y, Fukuhara M, Kawamori F, Otsuru M, Wu PF, Lin SY. Characterization of Orientia tsutsugamushi isolated in Taiwan by immunofluorescence and restriction fragment length polymorphism analyses. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1997.tb10374.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Fukuhara M, Fukazawa M, Tamura A, Nakamura T, Urakami H. Survival of two Orientia tsutsugamushi bacterial strains that infect mouse macrophages with varying degrees of virulence. Microb Pathog 2005; 39:177-87. [PMID: 16165341 DOI: 10.1016/j.micpath.2005.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 08/02/2005] [Accepted: 08/05/2005] [Indexed: 11/23/2022]
Abstract
Orientia tsutsugamushi, an intracellular parasitic bacterium, comprises numerous strains of differing virulence. When BALB/c mice were infected intraperitoneally with this pathogen, a virulent strain known as Karp was found to multiply in the intraperitoneal macrophages and kill the mouse. In contrast, an avirulent strain, Kuroki, was shown to invade macrophages but be eliminated from the cells, allowing mouse survival. O. tsutsugamushi invades its host cell cytoplasm through phagocytosis and disruption of phagosomal membranes but some bacteria are then killed by phago-lysosomes within 1h of infection. Microscopic observations could not differentiate the Karp and Kuroki strains during entry and subsequent cell killing by phago-lysosomes. However, the Kuroki cells failed to divide and were markedly deformed following cytoplasmic invasion at several days post-infection. These findings suggest that macrophages have a mechanism to eliminate O. tsutsugamushi in the cytoplasm, if the invading bacteria escape phagosomal clearance, and that it is this mechanism that Kuroki does not survive. Additionally, significant levels of nitric oxide (NO) are produced in macrophages by Kuroki, but not by Karp. An NO synthase inhibitor, however, does not increase the growth of Kuroki, suggesting that NO is induced in a strain-dependent manner but does not effect proliferation.
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Affiliation(s)
- Masahiro Fukuhara
- Laboratory of Microbiology, Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life Sciences (NUPALS), 265-1 Higashijima, Niigata 956-8603, Japan
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27
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Tay ST, Rohani YM, Ho TM, Shamala D. Sequence analysis of the hypervariable regions of the 56 kDa immunodominant protein genes of Orientia tsutsugamushi strains in Malaysia. Microbiol Immunol 2005; 49:67-71. [PMID: 15665455 DOI: 10.1111/j.1348-0421.2005.tb03641.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The DNA sequences encompassing two hypervariable regions, VD II and III of the 56 kDa immunodominant protein gene of 21 Malaysian strains of Orientia tsutsugamushi were determined. Two strains demonstrated a 100% DNA homology with the Gilliam prototype strain, and one with TH1817 strain and TA678 strain respectively. High percentages of DNA similarity (95-99%) were observed with Karp (4 strains), Gilliam (2 strains), TH1817 (4 strains), TC586 (3 strains) and TA763 (1 strain). The remaining strains demonstrated the highest DNA similarity with TA763 (1 strain, 89%), TA678 (1 strain, 86%) and TA686 (1 strain, 87%). Our study provides additional evidence on the existence and the genetic heterogeneity of TA strains of the Southeast Asia and their closely related strains in Malaysia.
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Affiliation(s)
- Sun Tee Tay
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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28
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Qiang Y, Tamura A, Urakami H, Makisaka Y, Koyama S, Fukuhara M, Kadosaka T. Phylogenetic characterization of Orientia tsutsugamushi isolated in Taiwan according to the sequence homologies of 56-kDa type-specific antigen genes. Microbiol Immunol 2003; 47:577-83. [PMID: 14524618 DOI: 10.1111/j.1348-0421.2003.tb03420.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Fourteen strains of Orientia tsutsugamushi isolated in Taiwan were characterized by sequencing 56-kDa type-specific antigen genes and patterns of restriction fragment length polymorphism (RFLP) predicted by a computer program. The strains showed high varieties in sequence homologies and were classified to 10 types by predicted patterns of RFLP. Furthermore, all Taiwan strains were not identical in typing with strains analyzed previously. These results suggest that there are various types of O. tsutsugamushi in Taiwan that are different from those distributed in other countries.
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Affiliation(s)
- Yu Qiang
- Department of Microbiology, Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life Sciences, Niigata, Niigata 950-2081, Japan
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29
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Yang Q, Ching WM, Jiang J, Lousteau L, Richards AL. An improved method for the purification and refolding of r56-kDa proteins from Gilliam and Kato strains of Orientia tsutsugamushi. Ann N Y Acad Sci 2003; 990:375-85. [PMID: 12860658 DOI: 10.1111/j.1749-6632.2003.tb07395.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The immunodominant 56kDa outer membrane antigens from Orientia tsutsugamushi Kato and Gilliam strains were expressed as inclusion bodies (IBs) in E. coli. The IBs were purified and properly refolded with modifications of a previous procedure used for the production of Karp strain r56 antigen. A mixture of these three r56 proteins exhibited both high sensitivity and specificity for detection of O. tsutsugamushi antibodies by ELISA.
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Affiliation(s)
- Qing Yang
- Rickettsial Diseases Program, Infectious Diseases Directorate, Naval Medical Research Center, Silver Spring, Maryland 20910, USA
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30
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Jang WJ, Huh MS, Park KH, Choi MS, Kim IS. Evaluation of an immunoglobulin M capture enzyme-linked immunosorbent assay for diagnosis of Orientia tsutsugamushi infection. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2003; 10:394-8. [PMID: 12738637 PMCID: PMC154952 DOI: 10.1128/cdli.10.3.394-398.2003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We developed an immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) for diagnosis of recent Orientia tsutsugamushi infections in humans. The 56-kDa major outer membrane protein of O. tsutsugamushi is well known as the most immunodominant antigen in scrub typhus. The test is based on the use of the biotinylated recombinant 56-kDa protein of O. tsutsugamushi Boryong, Bor56, which was expressed as a fusion protein with a maltose-binding protein in Escherichia coli. In the test, the serum IgM antibodies were captured by anti-human IgM antibodies coated onto a microtiter plate. The captured IgM antibodies were revealed through sequential addition of biotinylated Bor56 antigen and peroxidase-conjugated streptavidin to the plate. The IgM capture ELISA was compared with the immunofluorescence antibody assay (IFA) by testing 176 serum samples from patients with diagnosed cases of rickettsial disease and patients with other acute febrile diseases. Of the 81 IgG IFA-positive samples, 78 tested positive (sensitivity, 96.3%) and all 31 IgM IFA-positive samples tested positive (sensitivity, 100%) by the IgM capture ELISA. The specificity of the IgM capture ELISA was 99%, and 1 of the 95 IFA-negative samples was positive in the assay. These results strongly suggest that IgM capture ELISA using the recombinant Bor56 antigen is a reliable and detailed method for the detection of early O. tsutsugamushi infection.
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Affiliation(s)
- Won-Jong Jang
- Department of Microbiology, Kon-Kuk University College of Medicine, Choongju-si, Choongbuk 380-701, USA
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31
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Wang YC, Jian TY, Tarn LJ, Hung YW, Chao HY, Ji DD, Liu HW. Development of a recombinant protein-based enzyme-linked immunosorbent assay and its applications in field surveillance of rodent mice for presence of immunoglobulin G against Orientia tsutsugamushi. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2003; 10:451-8. [PMID: 12738648 PMCID: PMC154969 DOI: 10.1128/cdli.10.3.451-458.2003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A recombinant protein containing the immunodominant conserved epitope region of the 56-kDa outer membrane protein of the Karp strain of Orientia tsutsugamushi was purified to near homogeneity using recombinant DNA techniques. The purified protein was used to immunize rabbits and produced an antibody that could recognize different strains of O. tsutsugamushi, as demonstrated both by Western blotting and immunofluorescence assay. An enzyme-linked immunosorbent assay (ELISA) based on this recombinant protein was developed to detect antibody (immunoglobulin G [IgG]) against O. tsutsugamushi in mice captured in different districts of Taiwan during 2000 to 2001. A significant difference was found in the antibody seroprevalence rates of Suncus murinus mice captured in different districts of Taiwan (chi(2)(4, 0.95) = 26.64; P < 0.05). Furthermore, a significant difference of IgG seropositivity rates was observed among different kinds of mice (chi(2)(5, 0.95) = 93.85; P < 0.05). Antibody seropositivity rates were higher in Bandicota indica (100%), Rattus flavipectus (96.17%), and Rattus losea (95.83%) than in Rattus norvegicus (86.05%) and Rattus mindanensis (83.67%) (chi(2)(diff, 5, 0.95) = 12.59, P < 0.05). The lowest antibody seropositivity rate (54.4%) was observed in Suncus murinus. Antibody seropositivity rates of mice from different districts differed significantly because of the significant difference in antibody seroprevalence rates for S. murinus. The results of this study indicated that the recombinant protein ELISA developed in this study could be used to conduct large-scale surveillance of rodent mice for the presence of antibody against O. tsutsugamushi. The high seroprevalence rates in rodent mice (except S. murinus) suggest that people residing in these districts are at increased risk of developing O. tsutsugamushi infection.
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Affiliation(s)
- Yeau-Ching Wang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 100, Taiwan.
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32
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Kim MK, Odgerel Z, Chung MH, Lim BU, Kang JS. Characterization of monoclonal antibody reacting exclusively against intracellular Orientia tsutsugamushi. Microbiol Immunol 2003; 46:733-40. [PMID: 12516769 DOI: 10.1111/j.1348-0421.2002.tb02758.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intracellular bacteria often change the expression of their genes in order to adapt to new environmental conditions. Here we describe a monoclonal antibody (MAb) that reacts exclusively against intracellular Orientia tsutsugamushi. Although MAb applied to the 56-kDa protein, a major outer membrane protein, reacted against a large number of bacteria that had attached to host cells at the early stage of infection, M686-13 reacted against only a minor portion of the attached bacteria. In the later stage of the intracellular growth cycle, both antibodies showed identical staining patterns by double immunofluorescent staining. These results suggest that M686-13 reacted to an epitope or a protein that had probably been expressed during the intracellular growth cycle and rapidly diluted or degraded upon release into the extracellular environment. Although its molecular characteristics remain unknown, the reactive antigen may prove to be a novel developmental antigen and this MAb could be used as reagent for the staining of viable O. tsutsugamushi.
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Affiliation(s)
- Mee-Kyung Kim
- Department of Microbiology, Inha University College of Medicine, Inchon 400-103, Republic of Korea
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Moron CG, Popov VL, Feng HM, Wear D, Walker DH. Identification of the target cells of Orientia tsutsugamushi in human cases of scrub typhus. Mod Pathol 2001; 14:752-9. [PMID: 11504834 DOI: 10.1038/modpathol.3880385] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Orientia tsutsugamushi is the etiologic agent of scrub typhus, a chigger-borne zoonosis that is a highly prevalent, life-threatening illness of greatest public health importance in tropical Asia and the islands of the western Pacific Ocean. The target cell of this bacterium is poorly defined in humans. In this study, O. tsutsugamushi were identified by immunohistochemistry using a rabbit polyclonal antibody raised against O. tsutsugamushi Karp strain in paraffin-embedded archived autopsy tissues of three patients with clinical suspicion of scrub typhus who died during World War II and the Vietnam War. Rickettsiae were located in endothelial cells in all of the organs evaluated, namely heart, lung, brain, kidney, pancreas, and skin, and within cardiac muscle cells and in macrophages located in liver and spleen. Electron microscopy confirmed the location of rickettsiae in endothelium and cardiac myocytes.
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Affiliation(s)
- C G Moron
- Department of Pathology, University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555, USA
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Ching WM, Rowland D, Zhang Z, Bourgeois AL, Kelly D, Dasch GA, Devine PL. Early diagnosis of scrub typhus with a rapid flow assay using recombinant major outer membrane protein antigen (r56) of Orientia tsutsugamushi. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2001; 8:409-14. [PMID: 11238230 PMCID: PMC96071 DOI: 10.1128/cdli.8.2.409-414.2001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The variable 56-kDa major outer membrane protein of Orientia tsutsugamushi is the immunodominant antigen in human scrub typhus infections. We developed a rapid immunochromatographic flow assay (RFA) for the detection of immunoglobulin M (IgM) and IgG antibodies to O. tsutsugamushi. The RFA employs a truncated recombinant 56-kDa protein from the Karp strain as the antigen. The performance of the RFA was evaluated with a panel of 321 sera (serial bleedings of 85 individuals suspected of scrub typhus) which were collected in the Pescadore Islands, Taiwan, from 1976 to 1977. Among these 85 individuals, IgM tests were negative for 7 cases by both RFA and indirect fluorescence assay (IFA) using Karp whole-cell antigen. In 29 cases specific responses were detected by the RFA earlier than by IFA, 44 cases had the same detection time, and 5 cases were detected earlier by IFA than by RFA. For IgG responses, 4 individuals were negative with both methods, 37 cases exhibited earlier detection by RFA than IFA, 42 cases were detected at the same time, and 2 cases were detected earlier by IFA than by RFA. The sensitivities of RFA detection of antibody in sera from confirmed cases were 74 and 86% for IgM and IgG, respectively. When IgM and IgG results were combined, the sensitivity was 89%. A panel of 78 individual sera collected from patients with no evidence of scrub typhus was used to evaluate the specificity of the RFA. The specificities of the RFA were 99% for IgM and 97% for IgG. The sensitivities of IFA were 53 and 73% for IgM and IgG, respectively, and were 78% when the results of IgM and IgG were combined. The RFA test was significantly better than the IFA test for the early detection of antibody to scrub typhus in primary infections, while both tests were equally sensitive with reinfected individuals.
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Affiliation(s)
- W M Ching
- Viral and Ricksettial Diseases Department, Infectious Diseases Directorate, Code 41, Naval Medical Research Center, Bethesda, Maryland, USA.
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Pham XD, Otsuka Y, Suzuki H, Takaoka H. Detection of Orientia tsutsugamushi (Rickettsiales: rickettsiaceae) in unengorged chiggers (Acari: Trombiculidae) from Oita Prefecture, Japan, by nested polymerase chain reaction. JOURNAL OF MEDICAL ENTOMOLOGY 2001; 38:308-311. [PMID: 11296840 DOI: 10.1603/0022-2585-38.2.308] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The current study surveyed the 56-kDa type-specific antigen (TSA) gene DNAs of Orientia tsutsugamushi (Hayashi) in approximately 4.000 unengorged chiggers obtained from the soil or ground surface in an endemic and a nonendemic area of the Tsutsugamushi disease in Oita Prefecture, southwestern Japan, by nested polymerase chain reaction (PCR). Serotypes of O. tsutsugamushi were identified by restriction fragment-length polymorphism (RFLP) analysis. In the endemic area, 242 pools from five species [234 pools of Leptotrombidium scutellare (Nagayo, Miyagawa, Mitamura, Tamiya and Tenjin), two L. pallidum (Nagayo, Miyagawa, Mitamura and Tamiya), four L. kitasatoi (Fukuzumi & Obata), one L. fuji (Kuwata, Berge and Philip), and one Neotrombicula japonica (Tanaka, Kaiwa, Teramura and Kagaya)] were tested, and eight (seven pools of L. scutellare and one N. japonica) were positive for O. tsutsugamushi. Among the seven positive pools of L. scutellare, the distribution of serotypes was as follows: Kuroki (4), Gilliam (1), Karp (1), and Kawasaki (1). The first two serotypes (Kuroki and Gilliam) were identified for the first time in this species. In the nonendemic area, 128 pools from eight species were tested, and 13 were positive for O. tsutsugamushi. The positive rate was as follows: L. pallidum (4/41). L. kitasatoi (1/18), Gahrliepia saduski Womersley (2/10), L. fuji (4/50), L. himizu (Sasa, Kumada, Hayashi, Enomoto, Fukuzumi and Obata) (1/2), and Miyatrombicula kochiensis (Sasa, Kawashima and Egashira) (1/3). The latter three species were shown for the first time to harbor O. tsutsugamushi. All ofthe positive pools were Kuroki, except for two pools (one L. pallidum and one L. fuji), which were Gilliam (this serotype was also detected for the first time in L. pallidum). Further analysis revealed no differences in the nucleotide sequences (125 bp of variable domain 1 of TSA gene) of the same serotypes (i.e., Kuroki and Gilliam) among the positive samples. These data indicate that O. tsutsugamushi was widely distributed in various trombiculid species, even in the nonendemic area. The data are also suggestive of a possible horizontal transmission of O. tsutsugamushi among trombiculid species.
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Affiliation(s)
- X D Pham
- Department of Infectious Disease Control, Oita Medical University, Hasama, Japan
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36
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Abstract
Orientia tsutsugamushi, an obligate intracellular bacterium, was isolated for the first time in 1930. Infections by virulent strains are characterized by fever, rash, eschar, pneumonia, myocarditis, and disseminated intravascular coagulation. Here we review the general aspects of O. tsutsugamushi and immune responses in terms of inflammation, protective immune mechanisms, and immunogenic antigens.
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Affiliation(s)
- S Y Seong
- Department of Microbiology and Immunology, Seoul National University College of Medicine and Institute of Endemic Disease, Seoul National University Medical Research Center, 28 Yongon-dong, Chongno-gu, 110-799, Seoul, South Korea
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37
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Seong SY, Kim MK, Lee SM, Odgerel Z, Choi MS, Han TH, Kim IS, Kang JS, Lim BU. Neutralization epitopes on the antigenic domain II of the Orientia tsutsugamushi 56-kDa protein revealed by monoclonal antibodies. Vaccine 2000; 19:2-9. [PMID: 10924780 DOI: 10.1016/s0264-410x(00)00167-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Monoclonal antibodies (MoAbs) reactive with the authentic Orientia tsutsugamushi 56-kDa protein were generated. MoAb FS10 and FS15 showed in vitro, as well as, in vivo neutralizing activity upon O. tsutsugamushi infection. Deletion mutants of the gene for 56-kDa protein of O. tsutsugamushi Boryong were expressed to map the binding region. FS10 and FS15 are bound to amino acids (aa) located in an antigenic domain II, at residues 140-160 and 187-214, respectively. Computer modeling indicated that aa 146-153 were important for antigenicity against FS10. A sequence for aa 142-150 was highly homologous between oriential strains. These results suggest that the antigenic determinant for neutralizing MoAbs is an epitope within aa 140-160. Furthermore, this region may be important for the adhesion/invasion or intracellular survival of O. tsutsugamushi within host cells.
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Affiliation(s)
- S Y Seong
- Department of Microbiology and Immunology, Seoul National University College of Medicine and Institute of Endemic Disease, Seoul National University Medical Research Center, 28 Yongon-dong, Chongno-gu, 110-799, Seoul, South Korea
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38
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Enatsu T, Urakami H, Tamura A. Phylogenetic analysis of Orientia tsutsugamushi strains based on the sequence homologies of 56-kDa type-specific antigen genes. FEMS Microbiol Lett 1999; 180:163-9. [PMID: 10556707 DOI: 10.1111/j.1574-6968.1999.tb08791.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Close and distant relationship among 31 strains of Orientia tsutsugamushi (20, two, one and eight strains were isolated in Japan, Korea, China and southeast Asia, respectively) were clarified using phylogenetic analyses based on homologies of 56-kDa type-specific antigen genes. Isolates in Japan, Korea and China were located in eight separate clusters in the phylogenetic tree, and each was designated as JG (Japanese Gilliam type), JP-1 and JP-2 (Japanese Karp 1 and 2 types), Kato, Kawasaki, Kuroki, Shimokoshi and LX-1 types. All isolates originated in southeast Asia, including the prototype Gilliam and Karp strains isolated in Burma and New Guinea, respectively, were distantly located in the phylogenetic tree from those isolates in Japan, Korea and China, indicating that strains of O. tsutsugamushi distributed in northeastern and southeastern Asia are different types.
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Affiliation(s)
- T Enatsu
- Niigata College of Pharmacy, Department of Microbiology, 5-13-2 Kamishin'ei-cho, Niigata, Japan
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39
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Choi MS, Seong SY, Kang JS, Kim YW, Huh MS, Kim IS. Homotypic and heterotypic antibody responses to a 56-kilodalton protein of Orientia tsutsugamushi. Infect Immun 1999; 67:6194-7. [PMID: 10531289 PMCID: PMC97015 DOI: 10.1128/iai.67.11.6194-6197.1999] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed homotypic and heterotypic antibody responses to a type-specific antigen (Tsa), a 56-kDa protein of Orientia tsutsugamushi, by using sera from mice immunized with strains Gilliam, Karp, Kato, and Boryong. We generated a series of deletion constructs of the tsa gene and expressed them as MalE fusion proteins. Variable domain I (VD I) showed strong responses to homotypic antibodies. Antigenic domain II (AD II) from Boryong and Karp showed cross-reactivities to each other. VD III showed no responses to any of the antibodies. Sera from Kato-immunized mice showed only homotypic responses to AD III. On the other hand, sera of the mice immunized with Gilliam, Karp, or Boryong showed homotypic as well as heterotypic responses to this region. VD IV showed the strongest heterotypic antibody responses among the fragments tested. These data suggest that VD I is important in homotypic antibody responses and that AD II, AD III, and VD IV are important in heterotypic antibody responses of the mice to Tsa.
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Affiliation(s)
- M S Choi
- Department of Microbiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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40
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French DM, McElwain TF, McGuire TC, Palmer GH. Expression of Anaplasma marginale major surface protein 2 variants during persistent cyclic rickettsemia. Infect Immun 1998; 66:1200-7. [PMID: 9488414 PMCID: PMC108034 DOI: 10.1128/iai.66.3.1200-1207.1998] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Anaplasma marginale is an intraerythrocytic rickettsial pathogen of cattle in which infection persists for the life of the animal. Persistent A. marginale infection is characterized by repetitive rickettsemic cycles which we hypothesize reflect emergence of A. marginale antigenic variants. In this study, we determined whether variants of major surface protein 2 (MSP-2), a target of protective immunity encoded by a polymorphic multigene family, arise during persistent rickettsemia. By using a quantitative competitive PCR to identify rickettsemic cycles, msp-2 transcripts expressed in vivo were isolated from peak rickettsemia of sequential cycles. Cloning and sequencing of msp-2 cDNA revealed that genetic variants of MSP-2 emerge representing a minimum of four genetic variant types in each cycle during persistent infection. Two-color immunofluorescence using variant-specific antibody showed that emergence of MSP-2 variants resulted in expression of a minimum of three antigenic types of MSP-2 within one rickettsemic cycle. Therefore immune control of each cycle would require responses to an antigenically diverse A. marginale population. These findings demonstrate that polymorphic MSP-2 variants emerge during cyclic rickettsemia in persistent A. marginale infection and suggest that emergent variants play an important role in persistence.
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Affiliation(s)
- D M French
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164, USA.
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41
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Seong SY, Park SG, Huh MS, Jang WJ, Kim HR, Han TH, Choi MS, Chang WH, Kim IS. Mapping of antigenic determinant regions of the Bor56 protein of Orientia tsutsugamushi. Infect Immun 1997; 65:5250-6. [PMID: 9393823 PMCID: PMC175756 DOI: 10.1128/iai.65.12.5250-5256.1997] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The 56-kDa protein (Bor56) of Orientia tsutsugamushi is an immunoprotective antigen and is the target molecule of neutralizing antibodies. This antigen is recognized by almost all of the serum antibodies produced by patients in the convalescence phase of scrub typhus. We expressed the Bor56 open reading frame in Escherichia coli and generated from it a series of deletion constructs as MalE fusion proteins. Antibody-binding domains were characterized by using patient sera, mouse monoclonal antibodies (MAbs), and Bor56-immunized-mouse sera. None of the antibodies bound to a fusion protein containing the carboxy-terminal 140 amino acids (aa) of the Bor56 protein, suggesting that the carboxy-terminal domain of Bor56 is not exposed on the surface of the molecule. Human immunoglobulin M (IgM) antibodies predominantly bound to antigenic domain I (AD I; amino acids [aa] 19 to 113) and AD III (aa 243 to 328). Human IgG antibodies also showed preferential binding to AD I. The epitope recognized by strain-specific MAb (KI4) or group-specific MAb (KI57) was mapped to AD II (aa 142 to 203). Mouse serum antibodies, elicited by immunization with deletion mutants, consistently bound to AD III. Moreover, the carboxy-terminal 140 aa of the Bor56 protein did not elicit an antibody response in C3H/HeDub mice. A model of the antigenic structure of Bor56 is presented and discussed. These results suggest that antigenic fragments from AD I and AD III are useful in the induction of humoral immunity against O. tsutsugamushi. These antigenic analyses provide an important foundation for further analyses of the neutralizing-antibody responses generated during rickettsial infections. They also provide potential peptide substrates for diagnostic assays and vaccine strategies.
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Affiliation(s)
- S Y Seong
- Biomedical Research Center, Korea Institute of Science and Technology, Seoul
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42
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Seong SY, Kim HR, Huh MS, Park SG, Kang JS, Han TH, Choi MS, Chang WH, Kim IS. Induction of neutralizing antibody in mice by immunization with recombinant 56 kDa protein of Orientia tsutsugamushi. Vaccine 1997; 15:1741-7. [PMID: 9364677 DOI: 10.1016/s0264-410x(97)00112-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Anti-oriential antibody inhibits Orientia tsutsugamushi attachment to, and penetration of, host cells. However, O. tsutsugamushi antigens that induce the production of a neutralizing antibody have not been identified. The authors immunized mice and rabbits with the recombinant 56 kDa protein of O. tsutsugamushi fused to the maltose binding protein of Escherichia coli (MBP-Bor56) and analysed their effect on O. tsutsugamushi attachment to or penetration of L929 cells. O. tsutsugamushi attachment and penetration were measured by using an indirect immunofluorescent antibody assay (IFA). O. tsutsugamushi growth in L929 cells was determined by [3H]thymidine uptake assay. By IFA, we observed a 96% reduction of attachment or penetration of O. tsutsugamushi treated with rabbit anti-MBP-Bor56 sera. [3H]thymidine uptake showed that mouse anti-MBP-Bor56 sera caused a 91% reduction in O. tsutsugamushi growth, when compared to mouse anti-MBP sera. These results suggest that the 56 kDa protein of O. tsutsugamushi plays an important role in O. tsutsugamushi attachment to or penetration of cells.
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Affiliation(s)
- S Y Seong
- Department of Microbiology, Seoul National University College of Medicine, Chongno-gu, South Korea
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43
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Seong SY, Huh MS, Jang WJ, Park SG, Kim JG, Woo SG, Choi MS, Kim IS, Chang WH. Induction of homologous immune response to Rickettsia tsutsugamushi Boryong with a partial 56-kilodalton recombinant antigen fused with the maltose-binding protein MBP-Bor56. Infect Immun 1997; 65:1541-5. [PMID: 9119501 PMCID: PMC175167 DOI: 10.1128/iai.65.4.1541-1545.1997] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Although the 56-kDa protein of Rickettsia tsutsugamushi has been presumed to play important roles in generating protective immunity against scrub typhus, studies of this protein have been impeded. We used the recombinant 56-kDa protein of R. tsutsugamushi Boryong fused with the maltose-binding protein of Escherichia coli (MBP-Bor56) to analyze its ability to induce protective immunity in a C3H/HeDub murine model. Intraperitoneal immunization of mice with MBP-Bor56 resulted in an increase in the 50% minimal lethal dose of more than 160 times compared with that for the control mice. Splenic mononuclear cells from the mice immunized with MBP-Bor56 showed a dose-dependent pattern of lymphocyte proliferation response and secreted gamma interferon and interleukin-2 when stimulated with irradiated R. tsutsugamushi Boryong, which is a cytokine profile of Th1 cells. High titers of antibody to R. tsutsugamushi were also demonstrated by indirect immunofluorescent-antibody testing. These findings suggest that the 56-kDa protein of R. tsutsugamushi is one of the candidates for a vaccine against scrub typhus.
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Affiliation(s)
- S Y Seong
- Department of Microbiology, Seoul National University College of Medicine, Republic of Korea.
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44
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Seong SY, Park SG, Kim HR, Han TH, Kang JS, Choi MS, Kim IS, Chang WH. Isolation of a new Orientia tsutsugamushi serotype. Microbiol Immunol 1997; 41:437-43. [PMID: 9251054 DOI: 10.1111/j.1348-0421.1997.tb01876.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Orientia tsutsugamushi, the etiological agent of scrub typhus, is an antigenically diverse organism and many serologically distinct strains have been identified. The 56 kDa protein of O. tsutsugamushi, a major protein in the outer membrane, has been thought to be responsible for this antigenic variability. A strain of O. tsutsugamushi isolated in Korea cross-reacted with both Gilliam strain-specific and Karp strain-specific monoclonal antibodies. When its 56 kDa protein gene was cloned and analyzed, its sequence showed variation especially between 1,200 and 1,250 bp, showing that this isolate is a new O. tsutsugamushi strain.
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Affiliation(s)
- S Y Seong
- Department of Microbiology, Seoul National University College of Medicine, Republic of Korea
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45
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Ohashi N, Koyama Y, Urakami H, Fukuhara M, Tamura A, Kawamori F, Yamamoto S, Kasuya S, Yoshimura K. Demonstration of antigenic and genotypic variation in Orientia tsutsugamushi which were isolated in Japan, and their classification into type and subtype. Microbiol Immunol 1996; 40:627-38. [PMID: 8908607 DOI: 10.1111/j.1348-0421.1996.tb01120.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A total of 40 strains of Orientia tsutsugamushi (34 isolates from patients and trombiculid mites in Japan, and 6 prototype strains of antigenic variants) were examined for classification based on the reactivities with type-specific monoclonal antibodies in indirect immunofluorescence tests, and on the restriction fragment length polymorphism of a polymerase chain reaction (PCR)-amplified 56-kilodalton type-specific antigenic protein gene. By these methods, several antigenic and genotypic variants were found among the strains, and these variants were classified into types and further into subtypes. These results suggest that there are many variants in O. tsutsugamushi, and the methods used here seem to be useful for the systematic classification of the numerous variants. A strain which may be a new type distinguishable from those identified previously was also found in this study. Furthermore, variety in the degree of pathogenicity in mice related to type and/or subtype classification were observed.
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Affiliation(s)
- N Ohashi
- Department of Microbiology, Niigata College of Pharmacy, Japan
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46
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Kasuya S, Nagano I, Ikeda T, Goto C, Shimokawa K, Takahashi Y. Apoptosis of lymphocytes in mice induced by infection with Rickettsia tsutsugamushi. Infect Immun 1996; 64:3937-41. [PMID: 8751955 PMCID: PMC174319 DOI: 10.1128/iai.64.9.3937-3941.1996] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Histological examinations of mice infected with either a lethal (Karp) or a self-limitating (Gilliam) strain of Rickettsia tsutsugamushi were performed. Tingible body macrophages in the spleen and necrotizing lymphadenitis in regional lymph nodes were prominent only in the former. Apoptotic legions in the lymphocytes of these organs were clearly demonstrated by histochemical and electron microscopical examinations.
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Affiliation(s)
- S Kasuya
- Department of Parasitology, Gifu University School of Medicine, Japan
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47
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Ohashi N, Fukuhara M, Shimada M, Tamura A. Phylogenetic position of Rickettsia tsutsugamushi and the relationship among its antigenic variants by analyses of 16S rRNA gene sequences. FEMS Microbiol Lett 1995; 125:299-304. [PMID: 7875578 DOI: 10.1111/j.1574-6968.1995.tb07372.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The 16S rRNA gene sequences of Rickettsia tsutsugamushi and Rickettsia sibirica were determined by PCR and DNA sequencing. Phylogenetic analysis revealed that R. sibirica is positioned in a cluster of the genus Rickettsia with a similarity value of 98.1-99.6%, whereas R. tsutsugamushi is located apart from the cluster with a similarity value of 90.2-90.6%. This evidence suggests that R. tsutsugamushi should be excluded taxonomically from the genus Rickettsia. The phylogenetic classification of six antigenic variants in R. tsutsugamushi moderately reflected their antigenic relationship known in closely and distantly related strains.
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Affiliation(s)
- N Ohashi
- Department of Microbiology, Niigata College of Pharmacy, Japan
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48
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Kee SH, Choi IH, Choi MS, Kim IS, Chang WH. Detection of Rickettsia tsutsugamushi in Experimentally infected mice by PCR. J Clin Microbiol 1994; 32:1435-9. [PMID: 8077385 PMCID: PMC264015 DOI: 10.1128/jcm.32.6.1435-1439.1994] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We developed a rapid procedure for the detection of Rickettsia tsutsugamushi DNA by the PCR technique. The primer pair used for the PCR was designed from the DNA sequence of the gene encoding a 120-kDa antigen, which was proven to be group specific by immunoblot analysis with mouse hyperimmune sera against various rickettsial strains. This PCR method was able to detect up to 10 ag of plasmid DNA (pKT12). Specific PCR products were obtained with DNAs from R. tsutsugamushi Kato, Karp, Gilliam, TA716, TA1817, and Boryong, but not with DNAs from other rickettsiae, such as R. prowazekii, R. typhi, R. akari, and strain TT118. In a study with experimentally infected mice, the PCR method could detect rickettsial DNA from 2 days after inoculation (DAI), whereas serum antibody against R. tsutsugamushi could be detected from 6 to 8 DAI by an immunofluorescence test. Although clinical manifestations subsided after 14 DAI, rickettsial DNA in blood samples could be detected by PCR for up to 64 DAI. These results suggest that this PCR method can be applied to the early diagnosis of scrub typhus and can also be used to detect the residual rickettsiae after clinical symptoms subside.
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Affiliation(s)
- S H Kee
- Department of Microbiology, College of Medicine, Seoul National University, Republic of Korea
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49
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Amano K, Suzuki N, Fujita M, Nakamura Y, Suto T. Serological reactivity of sera from scrub typhus patients against Weil-Felix test antigens. Microbiol Immunol 1993; 37:927-33. [PMID: 8133798 DOI: 10.1111/j.1348-0421.1993.tb01726.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Sera from 17 patients of scrub typhus in the acute and convalescent phases were tested by indirect immunoperoxidase test, Weil-Felix (WF) test, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. In the comparison of antibody titers between acute- and convalescent-phase sera, we recognized a parallelism of increment between the titers in WF test and titers of immunoglobulin M (IgM) in ELISA against Proteus mirabilis strain OXK-whole cells and OXK-lipopolysaccharides (Proteus OXK-LPS). Furthermore, IgM antibodies from almost all of WF test-positive sera recognized LPS from Proteus OXK in immunoblotting. Based on these results, it was concluded that IgM antibody rather than IgG may participate in WF test, and that Proteus OXK-LPS may have one of antigenic epitopes common to the components of R. tsutsugamushi.
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Affiliation(s)
- K Amano
- Central Research Laboratory, Akita University School of Medicine, Japan
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50
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Lachumanan R, Devi S, Cheong YM, Rodda SJ, Pang T. Epitope mapping of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi. Infect Immun 1993; 61:4527-31. [PMID: 7691753 PMCID: PMC281195 DOI: 10.1128/iai.61.10.4527-4531.1993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Binding studies of 160 overlapping, synthetic octapeptides from the hydrophilic regions of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi with sera from patients with scrub typhus revealed 15 immunodominant peptides which are recognized by all the sera tested. Further analysis of the specificity of peptide binding with five of these peptides indicated that the peptides showed significantly stronger binding to scrub typhus patients' sera than they did to sera from patients with other febrile illnesses common in the region, i.e., malaria, dengue fever, typhoid fever, and leptospirosis. The main antibody class binding to these peptides appears to be immunoglobulin M, and there appears to be little correlation between reactivity with peptides and antibody titers measured by the indirect immunoperoxidase test.
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Affiliation(s)
- R Lachumanan
- Institute of Advanced Studies, University of Malaya, Kuala Lumpur
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