Characterization Based on the 56-Kda Type-Specific Antigen Gene of Orientia tsutsugamushi Genotypes Isolated from Leptotrombidium Mites and the Rodent Host Post-Infection

Takhampunya, Ratree; Tippayachai, Bousaraporn; Promsathaporn, Sommai; Leepitakrat, Surachai; Monkanna, Taweesak; Schuster, Anthony L.; Melendrez, Melanie C.; Paris, Daniel; Richards, Allen L.; Richardson, Jason H.

doi:10.4269/ajtmh.13-0393

Cited by 24 publications

(31 citation statements)

References 29 publications

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“…Bacterial dissemination was not followed in the mite transmission model, and thus it is impossible to compare this feature to our model, but the i.d. inoculation model did show remarkably rapid dissemination from the site of inoculation into the lungs as early as 24 hours post infection [42]. In the i.v.…”

Section: Discussionmentioning

confidence: 93%

A Hematogenously Disseminated Orientia tsutsugamsushi-Infected Murine Model of Scrub Typhus

Shelite

Saito²,

Mendell³

et al. 2014

PLoS Negl Trop Dis

150

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Orientia tsutsugamushi, the etiologic agent of scrub typhus, is a mite-borne rickettsia transmitted by the parasitic larval stage of trombiculid mites. Approximately one-third of the world's population is at risk of infection with Orientia tsutsugamushi, emphasizing its importance in global health. In order to study scrub typhus, Orientia tsutsugamushi Karp strain has been used extensively in mouse studies with various inoculation strategies and little success in inducing disease progression similar to that of human scrub typhus. The objective of this project was to develop a disease model with pathology and target cells similar to those of severe human scrub typhus. This study reports an intravenous infection model of scrub typhus in C57BL/6 mice. This mouse strain was susceptible to intravenous challenge, and lethal infection occurred after intravenous inoculation of 1.25×106 focus (FFU) forming units. Signs of illness in lethally infected mice appeared on day 6 with death occurring ∼6 days later. Immunohistochemical staining for Orientia antigens demonstrated extensive endothelial infection, most notably in the lungs and brain. Histopathological analysis revealed cerebral perivascular, lymphohistiocytic infiltrates, focal hemorrhages, meningoencephalitis, and interstitial pneumonia. Disseminated infection of endothelial cells with Orientia in C57BL/6 mice resulted in pathology resembling that of human scrub typhus. The use of this model will allow detailed characterization of the mechanisms of immunity to and pathogenesis of O. tsutsugamushi infection.

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Section: Discussionmentioning

confidence: 93%

A Hematogenously Disseminated Orientia tsutsugamsushi-Infected Murine Model of Scrub Typhus

Shelite

Saito²,

Mendell³

et al. 2014

PLoS Negl Trop Dis

150

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“…For example, the protein-coding genes: ftsZ, groEL, wsp and citrate synthase (gltA) were used in Wolbachia studies (Hong et al 2002;Gotoh et al 2005;Yu et al 2011;Lu et al 2012;Ros et al 2012;Suh et al 2014;Glowska et al 2015;Zhang et al 2015); outer membrane protein B gene, 17 kD antigenic gene and gltA were used for Rickettsia spp. (Literak et al 2008); the epank1 gene was used for Anaplasma phagocytophilum (Literak et al 2008); and the 56-kD type-specific antigen gene was used extensively for O. tsutsugamushi (Tamura et al 2000;Pham et al 2001;Khuntirat et al 2003;Lee et al 2011;Liu et al 2013;Seto et al 2013;Shin et al 2014;Takhampunya et al 2014). (Kabeya et al 2010;Kamani et al 2013); gyrB was used for Cardinium (Ros et al 2012;Zhu et al 2012); the 5S-23S ITS was used for Borrelia spp.…”

Section: Methodological Approaches To the Identification Of Bacteria mentioning

confidence: 99%

Symbiosis in an overlooked microcosm: a systematic review of the bacterial flora of mites

et al. 2015

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A dataset of bacterial diversity found in mites was compiled from 193 publications (from 1964 to January 2015). A total of 143 mite species belonging to the 3 orders (Mesostigmata, Sarcoptiformes and Trombidiformes) were recorded and found to be associated with approximately 150 bacteria species (in 85 genera, 51 families, 25 orders and 7 phyla). From the literature, the intracellular symbiont Cardinium, the scrub typhus agent Orientia, and Wolbachia (the most prevalent symbiont of arthropods) were the dominant mite-associated bacteria, with approximately 30 mite species infected each. Moreover, a number of bacteria of medical and veterinary importance were also reported from mites, including species from the genera Rickettsia, Anaplasma, Bartonella, Francisella, Coxiella, Borrelia, Salmonella, Erysipelothrix and Serratia. Significant differences in bacterial infection patterns among mite taxa were identified. These data will not only be useful for raising awareness of the potential for mites to transmit disease, but also enable a deeper understanding of the relationship of symbionts with their arthropod hosts, and may facilitate the development of intervention tools for disease vector control. This review provides a comprehensive overview of mite-associated bacteria and is a valuable reference database for future research on mites of agricultural, veterinary and/or medical importance.

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“…Also, during a natural chigger infection, there is the possibility of various strains of Orientia inhabiting the feeding mite, passing on various strains to the host. However, this is not the case with Lc-1, as only 1 sequence (94.2% similar to Karp) was found in the analysed chiggers [35]. Even though the intraperitoneal route has been used extensively and has facilitated the elucidation of the mechanism of action of diseases [15,28,29,53], alongside in the testing of vaccine candidates [20,54,55], it only takes a couple of seconds to introduce the infectious organisms into mice.…”

Section: Discussionmentioning

confidence: 99%

“…Primers with built-in BamH1 and NdeI restriction sites for the 56 kDa protein gene from amino acid 80-456 (according to the sequence of Karp strain) of the open reading frame were designed based on the available DNA sequences of Karp strain in the NCBI database. Genomic DNA extracted from the liver of mouse, which was infected by Lc-1 chiggers, was extracted as previously described using QiAamp DNA mini kit [35] and used in a polymerase chain reaction (PCR). The amplicons were cloned into a pET24a vector (Novagen, Wisconsin, USA).…”

Section: Cloning and Expression Of 56 Kda Protein Genes From Lc-1mentioning

confidence: 99%

“…Since the scrub typhus disease is transmitted via the bite of an infected chigger and rodent is the natural reservoir of chigger, the best way to evaluate a vaccine candidate is using the chigger-mouse feeding model, which has been established at The Armed Forces Research Institute of Medical Sciences, Thailand (AFRIMS) [33][34][35][36]. A total of 12 Orientia infected and 3 uninfected chigger lines derived from three Leptotrombidium species are maintained [21,33,34] at AFRIMS [33,34].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of a Recombinant Vaccine Candidate r56Lc-1 in a Chigger Challenge Mouse Model

Ching

Lurchachaiwong²,

Zhang³

et al. 2014

J Vaccines Vaccin

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Scrub typhus, an acute, febrile disease is transmitted by the bite of an Orientia infected chigger. We evaluated the protective potential of a recombinant 56 kDa antigen in a chigger challenge mouse model which mimics the natural transmission of Orientia. Chiggers from an L. chiangraiensis line 1 (Lc-1) was chosen for this challenge because the line produces chiggers with stable infectivity of 90-100% in several generations. The 56kD antigen gene of O. tsutsugamushi was cloned into an expression vector, expressed, purified, and refolded. All ICR mice were immunized 3 times at 4 weeks intervals and challenged by placing an individual chigger in the inner ear of each mouse 4 weeks after the last immunization. Mice were immunized with adjuvant Montanide+CpG or 25 g of r56Lc-1 emulsion with Montanide+CpG. Both groups were challenged by an individual Lc-1 chigger (un-infected or infected). There was no death in the groups of mice challenged by an uninfected chigger, with or without the vaccine candidate r56Lc-1. There was no survival in the groups of mice immunized with adjuvant only and challenged by an infected chigger. Our data demonstrated that r56Lc-1 provided 20-30% of protection consistently upon challenge by an infected chigger which carries the same Orientia strain based on the sequence of 56 kDa antigen. Time to mortality was delayed in mice immunized with the vaccine candidate then challenged with infected chiggers as compared to their adjuvant counterparts Since Orientia is an intracellular pathogen, the clearance of this pathogen may heavily depend on T-cell immune responses rather than B-cell immune responses and may require a vaccine candidate that mainly promotes T-cell immunity.

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Characterization Based on the 56-Kda Type-Specific Antigen Gene of Orientia tsutsugamushi Genotypes Isolated from Leptotrombidium Mites and the Rodent Host Post-Infection

Cited by 24 publications

References 29 publications

A Hematogenously Disseminated Orientia tsutsugamsushi-Infected Murine Model of Scrub Typhus

A Hematogenously Disseminated Orientia tsutsugamsushi-Infected Murine Model of Scrub Typhus

Symbiosis in an overlooked microcosm: a systematic review of the bacterial flora of mites

Evaluation of a Recombinant Vaccine Candidate r56Lc-1 in a Chigger Challenge Mouse Model

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