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Minahan NT, Yen TY, Guo YLL, Shu PY, Tsai KH. Concatenated ScaA and TSA56 Surface Antigen Sequences Reflect Genome-Scale Phylogeny of Orientia tsutsugamushi: An Analysis Including Two Genomes from Taiwan. Pathogens 2024; 13:299. [PMID: 38668254 PMCID: PMC11054523 DOI: 10.3390/pathogens13040299] [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: 03/08/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 04/29/2024] Open
Abstract
Orientia tsutsugamushi is an obligate intracellular bacterium associated with trombiculid mites and is the causative agent of scrub typhus, a life-threatening febrile disease. Strain typing of O. tsutsugamushi is based on its immunodominant surface antigen, 56-kDa type-specific antigen (TSA56). However, TSA56 gene sequence-based phylogenetic analysis is only partially congruent with core genome-based phylogenetic analysis. Thus, this study investigated whether concatenated surface antigen sequences, including surface cell antigen (Sca) proteins, can reflect the genome-scale phylogeny of O. tsutsugamushi. Complete genomes were obtained for two common O. tsutsugamushi strains in Taiwan, TW-1 and TW-22, and the core genome/proteome was identified for 11 O. tsutsugamushi strains. Phylogenetic analysis was performed using maximum likelihood (ML) and neighbor-joining (NJ) methods, and the congruence between trees was assessed using a quartet similarity measure. Phylogenetic analysis based on 691 concatenated core protein sequences produced identical tree topologies with ML and NJ methods. Among TSA56 and core Sca proteins (ScaA, ScaC, ScaD, and ScaE), TSA56 trees were most similar to the core protein tree, and ScaA trees were the least similar. However, concatenated ScaA and TSA56 sequences produced trees that were highly similar to the core protein tree, the NJ tree being more similar. Strain-level characterization of O. tsutsugamushi may be improved by coanalyzing ScaA and TSA56 sequences, which are also important targets for their combined immunogenicity.
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Affiliation(s)
- Nicholas T. Minahan
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
| | - Tsai-Ying Yen
- Centers for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 115210, Taiwan; (T.-Y.Y.); (P.-Y.S.)
| | - Yue-Liang Leon Guo
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
- Department of Environmental and Occupational Medicine, National Taiwan University (NTU) College of Medicine and NTU Hospital, Taipei 100025, Taiwan
| | - Pei-Yun Shu
- Centers for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 115210, Taiwan; (T.-Y.Y.); (P.-Y.S.)
| | - Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
- Global Health Program, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
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Kim CG, Kim WK, Kim N, Pyung YJ, Park DJ, Lee JC, Cho CS, Chu H, Yun CH. Intranasal Immunization With Nanoparticles Containing an Orientia tsutsugamushi Protein Vaccine Candidate and a Polysorbitol Transporter Adjuvant Enhances Both Humoral and Cellular Immune Responses. Immune Netw 2023; 23:e47. [PMID: 38188601 PMCID: PMC10767547 DOI: 10.4110/in.2023.23.e47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 12/08/2023] [Accepted: 12/10/2023] [Indexed: 01/09/2024] Open
Abstract
Scrub typhus, a mite-borne infectious disease, is caused by Orientia tsutsugamushi. Despite many attempts to develop a protective strategy, an effective preventive vaccine has not been developed. The identification of appropriate Ags that cover diverse antigenic strains and provide long-lasting immunity is a fundamental challenge in the development of a scrub typhus vaccine. We investigated whether this limitation could be overcome by harnessing the nanoparticle-forming polysorbitol transporter (PST) for an O. tsutsugamushi vaccine strategy. Two target proteins, 56-kDa type-specific Ag (TSA56) and surface cell Ag A (ScaA) were used as vaccine candidates. PST formed stable nano-size complexes with TSA56 (TSA56-PST) and ScaA (ScaA-PST); neither exhibited cytotoxicity. The formation of Ag-specific IgG2a, IgG2b, and IgA in mice was enhanced by intranasal vaccination with TSA56-PST or ScaA-PST. The vaccines containing PST induced Ag-specific proliferation of CD8+ and CD4+ T cells. Furthermore, the vaccines containing PST improved the mouse survival against O. tsutsugamushi infection. Collectively, the present study indicated that PST could enhance both Ag-specific humoral immunity and T cell response, which are essential to effectively confer protective immunity against O. tsutsugamushi infection. These findings suggest that PST has potential for use in an intranasal vaccination strategy.
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Affiliation(s)
- Cheol Gyun Kim
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
- Bio-MAX/N-Bio, Seoul National University, Seoul 08826, Korea
| | - Won Kyong Kim
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, National Institute of Health, Cheongju 28159, Korea
| | - Narae Kim
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Young Jin Pyung
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Da-Jeong Park
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Jeong-Cheol Lee
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Chong-Su Cho
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Hyuk Chu
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, National Institute of Health, Cheongju 28159, Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Korea
- Institutes of Green-bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
- Interdisciplinary Programs in Agricultural Genomics, Seoul National University, Seoul 08826, Korea
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An Alternative Splicing Variant of the Mixed-Lineage Leukemia 5 Protein Is a Cellular Adhesion Receptor for ScaA of Orientia tsutsugamushi. mBio 2023; 14:e0154322. [PMID: 36541760 PMCID: PMC9973269 DOI: 10.1128/mbio.01543-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Scrub typhus is a mite-borne disease caused by the obligately intracellular bacterium Orientia tsutsugamushi. We previously demonstrated that ScaA, an autotransporter membrane protein of O. tsutsugamushi, is commonly shared in various genotypes and involved in adherence to host cells. Here, we identified a mixed-lineage leukemia 5 (MLL5) mammalian trithorax group protein as a host receptor that interacts with ScaA. MLL5, identified by yeast two-hybrid screening, is an alternative splicing variant of MLL5 (vMLL5) which contains 13 exons with additional intron sequences encoding a tentative transmembrane domain. Indeed, vMLL5 is expressed on the plasma membrane as well as in intracellular compartments in eukaryotic cells and colocalized with adherent O. tsutsugamushi. In addition, ScaA-expressing Escherichia coli showed significantly increased adherence to vMLL5-overexpressing cells compared with vector control cells. We mapped the C-terminal region of the passenger domain of ScaA as a ligand for vMLL5 and determined that the Su(var)3-9, Enhancer of zeste, Trithorax (SET) domain of MLL5 is an essential and sufficient motif for ScaA binding. We observed significant and specific inhibition of bacterial adhesion to host cells in competitive inhibition assays using the C-terminal fragment of ScaA or the SET domain of vMLL5. Moreover, immunization with the C-terminal fragment of ScaA provided neutralizing activity and protective immunity against lethal challenge with O. tsutsugamushi as efficiently as vaccination with the whole passenger domain of ScaA. These results indicate that vMLL5 is a novel cellular receptor for ScaA-mediated adhesion of O. tsutsugamushi and facilitates bacterial adhesion to host cells, thereby enhancing bacterial infection. IMPORTANCE O. tsutsugamushi is a mite-borne pathogen that causes scrub typhus. As an obligately intracellular pathogen, its adhesion to and invasion of host cells are critical steps for bacterial growth. However, the molecular basis of the bacterial ligand and host receptor interaction is poorly defined. Here, we identified a splicing variant of MLL5 (vMLL5) as a cellular adhesion receptor of ScaA, an outer membrane autotransporter protein of O. tsutsugamushi. We mapped the interacting domains in the bacterial ligand and host receptor and confirmed their functional interaction. In addition, immunization with the C-terminal region of ScaA, which involves an interaction with the SET domain of vMLL5, not only induces enhanced neutralizing antibodies but also provides protective immunity against lethal challenge with O. tsutsugamushi.
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Bhandari M, Singh RK, Laishevtcev A, Mohapatra TM, Nigam M, Mori E, Vasconcelos de Lacerda BCG, Coutinho HDM, Mishra AP. Revisiting scrub typhus: A neglected tropical disease. Comp Immunol Microbiol Infect Dis 2022; 90-91:101888. [PMID: 36252451 DOI: 10.1016/j.cimid.2022.101888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/18/2022] [Accepted: 09/29/2022] [Indexed: 02/08/2023]
Abstract
Scrub typhus is an under diagnosed re-emerging vector borne disease caused by an intracellular gram negative bacteria, Orientia. The disease is commonly prevalent in rural and hilly areas of Tsutsugumashi triangle. The diagnosis of the disease is very challenging due to similarity of its early symptoms with other febrile illnesses, like dengue and COVID 19, as well as non-availability of rapid, reliable and cost-effective methods. Moreover, the diverse clinical presentation in severe cases make it significant health problem. The occupational and behavioral risks responsible for the transmission lead to urgent need of vaccine development against the disease. The complete knowledge about its pathogenesis and the interaction with host's immune cells may help the scientists in developing the appropriate diagnostic methods as well as the vaccines.
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Affiliation(s)
- Munni Bhandari
- Department of Microbiology, School of Life Sciences, Hemvati Nandan Bahuguna Garhwal University, Srinagar (Garhwal) 246174, India.
| | - Rahul Kunwar Singh
- Department of Microbiology, School of Life Sciences, Hemvati Nandan Bahuguna Garhwal University, Srinagar (Garhwal) 246174, India.
| | - Alexey Laishevtcev
- Federal Research Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Y.R. Kovalenko of the Russian Academy of Sciences, Moscow, Russia; Laboratory of Biocontrol and Antimicrobial Resistance, Orel State, University Named After I.S. Turgenev, Orel, Russia.
| | - Tribhuvan Mohan Mohapatra
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
| | - Manisha Nigam
- Department of Biochemistry, Hemvati Nandan Bahuguna Garhwal University, Srinagar Garhwal-246174, Uttarakhand, India.
| | - Edna Mori
- CECAPE - College of Dentistry, Av. Padre Cícero, 3917, Juazeiro do Norte, São José CE 63024-015, Brazil.
| | | | | | - Abhay Prakash Mishra
- Department of Pharmacology, Faculty of Health Science, University of Free State, Bloemfontein 9300, South Africa.
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Nguyen YTH, Kim C, Kim Y, Jeon K, Kim HI, Ha NY, Cho NH. The Orientia tsutsugamushi ScaB Autotransporter Protein Is Required for Adhesion and Invasion of Mammalian Cells. Front Microbiol 2021; 12:626298. [PMID: 33613493 PMCID: PMC7890071 DOI: 10.3389/fmicb.2021.626298] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/05/2021] [Indexed: 01/08/2023] Open
Abstract
Autotransporter proteins are widely present in Gram-negative bacteria. They play a pivotal role in processes related to bacterial pathogenesis, including adhesion, invasion, colonization, biofilm formation, and cellular toxicity. Bioinformatics analysis revealed that Orientia tsutsugamushi, the causative agent of scrub typhus, encodes six different autotransporter genes (scaA-scaF). Although four of these genes (scaA, scaC, scaD, and scaE) are present in diverse strains, scaB and scaF have been detected in only a limited number of strains. Previous studies have demonstrated that ScaA and ScaC are involved in the adherence of host cells. However, the putative function of other O. tsutsugamushi Sca proteins has not been studied yet. In this study, we show that scaB is transcribed and expressed on the surface of O. tsutsugamushi Boryong strain. Using a heterologous Escherichia coli expression system, we demonstrated that ScaB-expressing E. coli can successfully mediate adherence to and invasion into non-phagocytic cells, including epithelial and endothelial cells. In addition, pretreatment with a recombinant ScaB polypeptide inhibits the entry of O. tsutsugamushi into cultured mammalian cells. Finally, we also identified the scaB gene in the Kuroki and TA686 strains and observed high levels of sequence variation in the passenger domains. Here, we propose that the ScaB protein of O. tsutsugamushi can mediate both adhesion to and invasion into host cells in the absence of other O. tsutsugamushi genes and may play important roles in bacterial pathogenesis.
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Affiliation(s)
- Yen Thi Hai Nguyen
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea
| | - Chaewon Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, South Korea
| | - Kyeongseok Jeon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea
| | - Hong-Il Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, South Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea.,Institute of Endemic Diseases, Seoul National University Medical Research Center and Bundang Hospital, Seoul, South Korea
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Salje J. Cells within cells: Rickettsiales and the obligate intracellular bacterial lifestyle. Nat Rev Microbiol 2021; 19:375-390. [PMID: 33564174 DOI: 10.1038/s41579-020-00507-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 01/01/2023]
Abstract
The Rickettsiales are a group of obligate intracellular vector-borne Gram-negative bacteria that include many organisms of clinical and agricultural importance, including Anaplasma spp., Ehrlichia chaffeensis, Wolbachia, Rickettsia spp. and Orientia tsutsugamushi. This Review provides an overview of the current state of knowledge of the biology of these bacteria and their interactions with host cells, with a focus on pathogenic species or those that are otherwise important for human health. This includes a description of rickettsial genomics, bacterial cell biology, the intracellular lifestyles of Rickettsiales and the mechanisms by which they induce and evade the innate immune response.
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Affiliation(s)
- Jeanne Salje
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK. .,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Public Health Research Institute, Rutgers University, Newark, NJ, USA.
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Sankar S, Saravanan N, Rajendiran P, Ramamurthy M, Sasimohan A, Vineeta V, Varghese G, Idikula M, Jesudason M, Mangalakumar R, Nair A, Babujanarthanam R, Nandagopal B, Sridharan G. Detection of scrub typhus by real-time polymerase chain reaction and immunoglobulin M ELISA among patients with acute febrile illness. J Nat Sci Biol Med 2020. [DOI: 10.4103/jnsbm.jnsbm_156_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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