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Londoño AF, Scorpio DG, Dumler JS. Innate immunity in rickettsial infections. Front Cell Infect Microbiol 2023; 13:1187267. [PMID: 37228668 PMCID: PMC10203653 DOI: 10.3389/fcimb.2023.1187267] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023] Open
Abstract
Rickettsial agents are a diverse group of alpha-proteobacteria within the order Rickettsiales, which possesses two families with human pathogens, Rickettsiaceae and Anaplasmataceae. These obligate intracellular bacteria are most frequently transmitted by arthropod vectors, a first step in the pathogens' avoidance of host cell defenses. Considerable study of the immune responses to infection and those that result in protective immunity have been conducted. Less study has focused on the initial events and mechanism by which these bacteria avoid the innate immune responses of the hosts to survive within and propagate from host cells. By evaluating the major mechanisms of evading innate immunity, a range of similarities among these bacteria become apparent, including mechanisms to escape initial destruction in phagolysosomes of professional phagocytes, those that dampen the responses of innate immune cells or subvert signaling and recognition pathways related to apoptosis, autophagy, proinflammatory responses, and mechanisms by which these microbes attach to and enter cells or those molecules that trigger the host responses. To illustrate these principles, this review will focus on two common rickettsial agents that occur globally, Rickettsia species and Anaplasma phagocytophilum.
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Affiliation(s)
- Andrés F. Londoño
- The Henry M. Jackson Foundation for Advancement in Military Medicine, Bethesda, MD, United States
- Department of Pathology, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Diana G. Scorpio
- Host-Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - J. Stephen Dumler
- Department of Pathology, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Liveris D, Aguero-Rosenfeld ME, Daniels TJ, Karpathy S, Paddock C, Adish S, Keesing F, Ostfeld RS, Wormser GP, Schwartz I. A new genetic approach to distinguish strains of Anaplasma phagocytophilum that appear not to cause human disease. Ticks Tick Borne Dis 2021; 12:101659. [PMID: 33497885 DOI: 10.1016/j.ttbdis.2021.101659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 11/20/2022]
Abstract
Genetic diversity of Anaplasma phagocytophilum was assessed in specimens from 16 infected patients and 16 infected Ixodes scapularis ticks. A region immediately downstream of the 16S rRNA gene, which included the gene encoding SdhC, was sequenced. For the A. phagocytophilum strains from patients no sequence differences were detected in this region. In contrast, significantly fewer ticks had a sequence encoding SdhC that was identical to that of the human strains (11/16 vs. 16/16, p = 0.04). This variation is consistent with the premise that not all A. phagocytophilum strains present in nature are able to cause clinical illness in humans. A strain referred to as A. phagocytophilumVariant-1 that is regarded as non-pathogenic for humans was previously described using a different typing method. Data from the current study suggest that both typing methods are identifying the same non-pathogenic strains.
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Affiliation(s)
- Dionysios Liveris
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Maria E Aguero-Rosenfeld
- Department of Pathology, New York Medical College, Valhalla, NY, United States; Department of Pathology, New York University Langone Health, NY, United States
| | - Thomas J Daniels
- Vector Ecology Laboratory, Louis Calder Center, Fordham University Armonk, NY, United States
| | - Sandor Karpathy
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Christopher Paddock
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Sahar Adish
- Cary Institute of Ecosystem Studies, Millbrook, NY, United States
| | - Felicia Keesing
- Program in Biology, Bard College, Annandale-on-Hudson, NY, United States
| | | | - Gary P Wormser
- Division of Infectious Diseases, New York Medical College, Valhalla, NY, United States
| | - Ira Schwartz
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States; Division of Infectious Diseases, New York Medical College, Valhalla, NY, United States.
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Scorpio DG, Choi KS, Dumler JS. Anaplasma phagocytophilum-Related Defects in CD8, NKT, and NK Lymphocyte Cytotoxicity. Front Immunol 2018; 9:710. [PMID: 29686681 PMCID: PMC5900440 DOI: 10.3389/fimmu.2018.00710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/22/2018] [Indexed: 12/19/2022] Open
Abstract
Human granulocytic anaplasmosis, caused by the tick-transmitted Anaplasma phagocytophilum, is not controlled by innate immunity, and induces a proinflammatory disease state with innate immune cell activation. In A. phagocytophilum murine infection models, hepatic injury occurs with production of IFNγ thought to be derived from NK, NKT cells, and CD8 T lymphocytes. Specific A. phagocytophilum ligands that drive inflammation and disease are not known, but suggest a clinical and pathophysiologic basis strikingly like macrophage activation syndrome (MAS) and hemophagocytic syndrome (HPS). We studied in vivo responses of NK, NKT, and CD8 T lymphocytes from infected animals for correlates of lymphocyte-mediated cytotoxicity and examined in vitro interactions with A. phagocytophilum-loaded antigen-presenting cells (APCs). Murine splenocytes were examined and found deficient in cytotoxicity as determined by CD107a expression in vitro for specific CTL effector subsets as determined by flow cytometry. Moreover, A. phagocytophilum-loaded APCs did not lead to IFNγ production among CTLs in vitro. These findings support the concept of impaired cytotoxicity with A. phagocytophilum presentation by APCs that express MHC class I and that interact with innate and adaptive immune cells with or after infection. The findings strengthen the concept of an enhanced proinflammatory phenotype, such as MAS and HPS disease states as the basis of disease and severity with A. phagocytophilum infection, and perhaps by other obligate intracellular bacteria.
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Affiliation(s)
- Diana G Scorpio
- Vaccine Research Center, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kyoung-Seong Choi
- College of Ecology and Environmental Science, Kyungpook National University, Sangju, South Korea
| | - J Stephen Dumler
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Troese MJ, Kahlon A, Ragland SA, Ottens AK, Ojogun N, Nelson KT, Walker NJ, Borjesson DL, Carlyon JA. Proteomic analysis of Anaplasma phagocytophilum during infection of human myeloid cells identifies a protein that is pronouncedly upregulated on the infectious dense-cored cell. Infect Immun 2011; 79:4696-707. [PMID: 21844238 PMCID: PMC3257945 DOI: 10.1128/iai.05658-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 08/02/2011] [Indexed: 01/31/2023] Open
Abstract
Anaplasma phagocytophilum is an obligate intracellular bacterium that invades neutrophils to cause the emerging infectious disease human granulocytic anaplasmosis. A. phagocytophilum undergoes a biphasic developmental cycle, transitioning between an infectious dense-cored cell (DC) and a noninfectious reticulate cell (RC). To gain insights into the organism's biology and pathogenesis during human myeloid cell infection, we conducted proteomic analyses on A. phagocytophilum organisms purified from HL-60 cells. A total of 324 proteins were unambiguously identified, thereby verifying 23.7% of the predicted A. phagocytophilum proteome. Fifty-three identified proteins had been previously annotated as hypothetical or conserved hypothetical. The second most abundant gene product, after the well-studied major surface protein 2 (P44), was the hitherto hypothetical protein APH_1235. APH_1235 homologs are found in other Anaplasma and Ehrlichia species but not in other bacteria. The aph_1235 RNA level is increased 70-fold in the DC form relative to that in the RC form. Transcriptional upregulation of and our ability to detect APH_1235 correlate with RC to DC transition, DC exit from host cells, and subsequent DC binding and entry during the next round of infection. Immunoelectron microscopy pronouncedly detects APH_1235 on DC organisms, while detection on RC bacteria minimally, at best, exceeds background. This work represents an extensive study of the A. phagocytophilum proteome, discerns the complement of proteins that is generated during survival within human myeloid cells, and identifies APH_1235 as the first known protein that is pronouncedly upregulated on the infectious DC form.
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Affiliation(s)
| | | | | | - Andrew K. Ottens
- Anatomy and Neurobiology
- Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | | | - Kristina T. Nelson
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia
| | - Naomi J. Walker
- Department of Pathology, Microbiology, and Immunology, University of California School of Veterinary Medicine, Davis, California 95616
| | - Dori L. Borjesson
- Department of Pathology, Microbiology, and Immunology, University of California School of Veterinary Medicine, Davis, California 95616
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Troese MJ, Carlyon JA. Anaplasma phagocytophilum dense-cored organisms mediate cellular adherence through recognition of human P-selectin glycoprotein ligand 1. Infect Immun 2009; 77:4018-27. [PMID: 19596771 PMCID: PMC2738047 DOI: 10.1128/iai.00527-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 06/08/2009] [Accepted: 07/07/2009] [Indexed: 01/20/2023] Open
Abstract
Anaplasma phagocytophilum is an obligate intracellular bacterium that infects granulocytes to cause human granulocytic anaplasmosis. The susceptibilities of human neutrophils and promyelocytic HL-60 cells to A. phagocytophilum are linked to bacterial usage of P-selectin glycoprotein ligand 1 (PSGL-1) as a receptor for adhesion and entry. A. phagocytophilum undergoes a biphasic developmental cycle, transitioning between a smaller electron dense-cored cell (DC), which has a dense nucleoid, and a larger, pleomorphic electron lucent reticulate cell (RC), which has a dispersed nucleoid. The pathobiological roles of each form have not been elucidated. To ascertain the role of each form, we used electron microscopy to monitor bacterial binding, entry, and intracellular development within HL-60 cells. Only DCs were observed binding to and inducing uptake by HL-60 cells. By 12 h, internalized DCs had transitioned to RCs, which had initiated replication. By 24 h, large RC numbers were observed within individual inclusions. Reinfection had occurred by 36 h, as individual, vacuole-enclosed DCs and RCs were again observed. The abilities of DC- and RC-enriched A. phagocytophilum populations to bind and/or infect HL-60 cells or Chinese hamster ovary cells transfected to express PSGL-1 (PSGL-1 CHO) were compared. Only DCs bound PSGL-1 CHO cells and did so in a PSGL-1-blocking antibody-inhibitable manner. These results demonstrate that the respective roles of A. phagocytophilum DCs and RCs are consistent with analogous forms of other obligate intracellular pathogens that undergo biphasic development and hint that the PSGL-1-targeting adhesin(s) may be upregulated or optimally posttranslationally modified on DCs.
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Affiliation(s)
- Matthew J Troese
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0678, USA
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Culture, isolation, and labeling of Anaplasma phagocytophilum for subsequent infection of human neutrophils. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008. [PMID: 18287755 DOI: 10.1007/978-1-60327-032-8_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Anaplasma phagocytophilum is the etiologic agent of granulocytic anaplasmosis, a tick-borne, zoonotic, emerging infectious disease. A. phagocytophilum is an obligate intracellular pathogen that primarily resides within membrane-bound, cytoplasmic vacuoles of host neutrophils. Closely related to Ehrlichial and Rickettsial organisms, A. phagocytophilum is a small, fragile, Gram-negative bacterium that presents unique challenges for culture, isolation, enumeration, and labeling. This chapter delineates pathogen-specific considerations for culture and labeling of this organism for subsequent use in assays to examine mechanisms of host cell-pathogen interactions.
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Wormser GP, Filozov A, Telford SR, Utpat S, Kamer RS, Liveris D, Wang G, Zentmaier L, Schwartz I, Aguero-Rosenfeld ME. Dissociation between Inhibition and Killing by Levofloxacin in Human Granulocytic Anaplasmosis. Vector Borne Zoonotic Dis 2006; 6:388-94. [PMID: 17187574 DOI: 10.1089/vbz.2006.6.388] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human granulocytic anaplasmosis (HGA) is a potentially fatal tick-borne infection caused by Anaplasma phagocytophilum. Treatment options are limited for this entity, with doxycycline being the drug of choice. Certain fluoroquinolones such as levofloxacin are active against A. phagocytophilum in vitro. We report a hospitalized patient with HGA who improved coincident with a 13-day course of levofloxacin therapy, but clinically and microbiologically relapsed 15 days after completion of treatment. Relapse of infection after levofloxacin therapy was reproduced in a severe combined immune-deficient (SCID) mouse infection model. Quinolone therapy should not be considered curative of HGA.
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Affiliation(s)
- Gary P Wormser
- Division of Infectious Diseases, Depatment of Medicine, New York Medical College, Westcheser Medical Center, Valhalla, New York, USA.
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Park J, Choi KS, Dumler JS. Major surface protein 2 of Anaplasma phagocytophilum facilitates adherence to granulocytes. Infect Immun 2003; 71:4018-25. [PMID: 12819090 PMCID: PMC161989 DOI: 10.1128/iai.71.7.4018-4025.2003] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaplasma phagocytophilum is an obligate intracellular bacterium that infects myeloid cells in the mammalian host. Msp2 (p44) is the major immunodominant outer-membrane protein of these bacteria. We hypothesized that Msp2 acts as an adhesin for A. phagocytophilum entry into granulocytes. This potential role was investigated by blocking binding with Msp2 monoclonal antibodies and by antagonizing binding and propagation with recombinant Msp2 (rMsp2) in vitro. With HL-60 cells, fresh human peripheral blood neutrophils, and a cell line devoid of the fucosylated platelet selectin glycoprotein ligand 1 (PSGL-1) receptor for A. phagocytophilum or one that was transfected to express this ligand, Msp2 monoclonal antibody and rMsp2 used as the antagonist caused concentration-dependent reductions in bacterial adhesion (P < 0.007 and P < 0.02, respectively) and propagation (P < 0.05 and P < 0.001), although inhibition of adhesion or propagation was moderate and incomplete. Likewise, rMsp2 bound to surfaces of the transfected cell at a level similar to that of extracellular A. phagocytophilum and significantly (P < 0.05) beyond that of nontransfected cells. Moreover, a dose-dependent reduction (P < 0.019) in PSGL-1 monoclonal antibody binding to HL-60 cells was elicited with rMsp2. We conclude that Msp2s of A. phagocytophilum are involved in bacterial adhesion to ligands on host myeloid cells before intracellular infection.
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Affiliation(s)
- Jinho Park
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Chaput EK, Meek JI, Heimer R. Spatial analysis of human granulocytic ehrlichiosis near Lyme, Connecticut. Emerg Infect Dis 2002; 8:943-8. [PMID: 12194771 PMCID: PMC2732548 DOI: 10.3201/eid0809.020103] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Geographic information systems combined with methods of spatial analysis provide powerful new tools for understanding the epidemiology of diseases and for improving disease prevention and control. In this study, the spatial distribution of a newly recognized tick-borne disease, human granulocytic ehrlichiosis (HGE), was investigated for nonrandom patterns and clusters in an area known to be endemic for tick-borne diseases. Analysis of confirmed cases of HGE identified in 1997-2000 in a 12-town area around Lyme, Connecticut, showed that HGE infections are not distributed randomly. Smoothed HGE incidence was higher around the mouth of the Connecticut River and lower to the north and west. Cluster analysis identified one area of increased HGE risk (relative risk=1.8, p=0.001). This study demonstrates the utility of geographic information systems and spatial analysis to clarify the epidemiology of HGE.
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Plier ML, Young KM, Barlough JE, Madigan JE, Dumler JS. Equine granulocytic ehrlichiosis: a case report with DNA analysis and species comparison. Vet Clin Pathol 2002; 28:127-130. [PMID: 12075508 DOI: 10.1111/j.1939-165x.1999.tb01062.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michelle L. Plier
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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Zeman P, Cinatl J, Kabickova H. Sodium valproate facilitates the propagation of granulocytic ehrlichiae (Anaplasma phagocytophilum) in HL-60 cells. EXPERIMENTAL & APPLIED ACAROLOGY 2002; 28:203-208. [PMID: 14570132 DOI: 10.1023/a:1025398432754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
As already shown, some inducers of the differentiation of promyelocytic cells along the granulocytic pathway, such as dimethylsulphoxide (DMSO) or all-trans retinoic acid, can enhance propagation of granulocytic ehrlichiae in HL-60 cell cultures. This study was conducted to prove whether sodium valproate, a salt of di-n-propylacetic acid (VPA) known to trigger cellular differentiation in several solid and hematopoietic malignancies is similarly efficient in ehrlichial cultures. Two cell lines derived from HL-60, that is, low-passage undifferentiated HL-60 (HL-60F) and high-passage HL-60 spontaneously differentiated towards monocytic phenotype (HL-60J) were grown in RPMI 1640 medium supplemented with 10% FBS. The respective HL-60F and HL-60J IC50-values for NaVPA were estimated to be 0.8 and 2.2 mM under these culture conditions; to stimulate the differentiation, the respective doses of 0.3 and 1.2 mM were then applied. When the NaVPA-treated cells of both lines were challenged with an ehrlichial laboratory strain (HGE), maintained in splenectomized NMRI mice, the respective 1-2 and < or = 0.1% primary infection rates in HL-60F and HL-60J cultures were observed 3 days post-inoculation. In comparison, only rare (< or = 0.1%) infected HL-60F and no infected HL-60J cells were recorded under the same experimental conditions in untreated control cultures. HGE continuously propagated in NaVPA-supplemented HL-60F cultures remained infectious to mice at least up to the 95th passage (12 months). NaVPA can thus facilitated continuous propagation of granulocytic ehrlichiae in cell cultures without a substantial loss of infectiveness.
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Affiliation(s)
- Petir Zeman
- Regional Center of Hygiene, Dittrichova 17, 120 00, Prague 2, Czech Republic.
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Inokuma H, Brouqui P, Drancourt M, Raoult D. Citrate synthase gene sequence: a new tool for phylogenetic analysis and identification of Ehrlichia. J Clin Microbiol 2001; 39:3031-9. [PMID: 11526124 PMCID: PMC88292 DOI: 10.1128/jcm.39.9.3031-3039.2001] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sequence of the citrate synthase gene (gltA) of 13 ehrlichial species (Ehrlichia chaffeensis, Ehrlichia canis, Ehrlichia muris, an Ehrlichia species recently detected from Ixodes ovatus, Cowdria ruminantium, Ehrlichia phagocytophila, Ehrlichia equi, the human granulocytic ehrlichiosis [HGE] agent, Anaplasma marginale, Anaplasma centrale, Ehrlichia sennetsu, Ehrlichia risticii, and Neorickettsia helminthoeca) have been determined by degenerate PCR and the Genome Walker method. The ehrlichial gltA genes are 1,197 bp (E. sennetsu and E. risticii) to 1,254 bp (A. marginale and A. centrale) long, and GC contents of the gene vary from 30.5% (Ehrlichia sp. detected from I. ovatus) to 51.0% (A. centrale). The percent identities of the gltA nucleotide sequences among ehrlichial species were 49.7% (E. risticii versus A. centrale) to 99.8% (HGE agent versus E. equi). The percent identities of deduced amino acid sequences were 44.4% (E. sennetsu versus E. muris) to 99.5% (HGE agent versus E. equi), whereas the homology range of 16S rRNA genes was 83.5% (E. risticii versus the Ehrlichia sp. detected from I. ovatus) to 99.9% (HGE agent, E. equi, and E. phagocytophila). The architecture of the phylogenetic trees constructed by gltA nucleotide sequences or amino acid sequences was similar to that derived from the 16S rRNA gene sequences but showed more-significant bootstrap values. Based upon the alignment analysis of the ehrlichial gltA sequences, two sets of primers were designed to amplify tick-borne Ehrlichia and Neorickettsia genogroup Ehrlichia (N. helminthoeca, E. sennetsu, and E. risticii), respectively. Tick-borne Ehrlichia species were specifically identified by restriction fragment length polymorphism (RFLP) patterns of AcsI and XhoI with the exception of E. muris and the very closely related ehrlichia derived from I. ovatus for which sequence analysis of the PCR product is needed. Similarly, Neorickettsia genogroup Ehrlichia species were specifically identified by RFLP patterns of RcaI digestion. If confirmed this technique will be useful in rapidly identifying Ehrlichia spp.
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Affiliation(s)
- H Inokuma
- Laboratory of Veterinary Internal Medicine, Faculty of Agriculture, Yamaguchi University, 753-8515 Yamaguchi, Japan
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Magnarelli LA, Ijdo JW, Van Andel AE, Wu C, Fikrig E. Evaluation of a polyvalent enzyme-linked immunosorbent assay incorporating a recombinant p44 antigen for diagnosis of granulocytic ehrlichiosis in dogs and horses. Am J Vet Res 2001; 62:29-32. [PMID: 11197555 DOI: 10.2460/ajvr.2001.62.29] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To develop and evaluate a polyvalent ELISA incorporating a highly specific recombinant antigen (p44) for diagnosis of granulocytic ehrlichiosis in dogs and horses. ANIMALS 32 dogs and 43 horses. PROCEDURE Results of the ELISA were compared with results of indirect fluorescent antibody (IFA) staining and western immunoblotting incorporating whole-cell antigen. RESULTS For the canine and equine samples, percentages of samples with positive IFA staining, western immunoblotting, and ELISA results were similar. For 29 (91 %) canine samples and 30 (70%) equine samples, results of IFA staining, western immunoblotting, and the ELISA were in complete agreement. Results of the ELISA for 3 canine serum samples known to contain antibodies to Ehrlichia canis and 12 equine serum samples known to contain antibodies to E risticii were negative. CONCLUSIONS AND CLINICAL RELEVANCE Results of the present study suggest that a polyvalent ELISA incorporating a recombinant p44 antigen is suitable for detecting antibodies to E equi in dogs and horses.
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Affiliation(s)
- L A Magnarelli
- Department of Entomology, Connecticut Agricultural Experiment Station, New Haven 06504, USA
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Magnarelli LA, Ijdo JW, Van Andel AE, Wu C, Padula SJ, Fikrig E. Serologic confirmation of Ehrlichia equi and Borrelia burgdorferi infections in horses from the northeastern United States. J Am Vet Med Assoc 2000; 217:1045-50. [PMID: 11019714 DOI: 10.2460/javma.2000.217.1045] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine whether horses living in tick-infested areas of northeastern United States with clinical signs of borreliosis or granulocytic ehrlichiosis had detectable serum antibodies to both Borrelia burgdorferi and Ehrlichia equi. DESIGN Prospective study. ANIMALS Serum samples from 51 clinically normal horses, 14 horses with clinical signs of borreliosis, and 17 horses with clinical signs of granulocytic ehrlichiosis. PROCEDURE Serum B burgdorferi or E equi antibodies were measured by use of an ELISA, immunoblot analysis, or indirect fluorescent antibody (IFA) staining. RESULTS Of the 82 serum samples tested, 37 (45.1%) and 13 (15.9%) had detectable antibodies to B burgdorferi or E equi, respectively. Test results indicated that 12 horses had been exposed to both agents, 11 of these horses had granulocytic ehrlichiosis. The ELISA regularly detected antibodies to the following recombinant protein (p) antigens of B burgdorferi: p29, p37, p39, and p41-G. The use of immunoblot analysis confirmed ELISA results by indicating antibody reactivities to antigens of whole-cell B burgdorferi having molecular masses of predominantly 31, 34, 37, 39, 41, 58, and 93 kd. CONCLUSIONS AND CLINICAL RELEVANCE Horses living in areas where ticks (Ixodes scapularis) abound are sometimes exposed to multiple pathogens. Analyses for specific recombinant borrelial antibodies using an ELISA can help separate horses with borreliosis from those with granulocytic ehrlichiosis, even when antibodies to both etiologic agents are detected in serum samples. Analysis using immunoblots is sensitive, and along with ELISA or IFA procedures, is suitable for confirming a clinical diagnosis of each disease.
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Affiliation(s)
- L A Magnarelli
- Department of Entomology, Connecticut Agricultural Experiment Station, New Haven 06504, USA
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Banerjee R, Anguita J, Fikrig E. Granulocytic ehrlichiosis in mice deficient in phagocyte oxidase or inducible nitric oxide synthase. Infect Immun 2000; 68:4361-2. [PMID: 10858261 PMCID: PMC101771 DOI: 10.1128/iai.68.7.4361-4362.2000] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mice deficient in phox (gp91(phox-/-)) or NOS2 (NOS2(-/-)) were infected with the agent of human granulocytic ehrlichiosis (HGE) to evaluate the importance of these pathways in the eradication of HGE bacteria. NOS2(-/-) mice had delayed clearance of the HGE agent in comparison to control or gp91(phox-/-) mice, suggesting that reactive nitrogen intermediates play a role in the early control of HGE.
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Affiliation(s)
- R Banerjee
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Banerjee R, Anguita J, Roos D, Fikrig E. Cutting edge: infection by the agent of human granulocytic ehrlichiosis prevents the respiratory burst by down-regulating gp91phox. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:3946-9. [PMID: 10754283 DOI: 10.4049/jimmunol.164.8.3946] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The agent of human granulocytic ehrlichiosis (HGE) is an emerging tick-borne pathogen that resides in neutrophils and can be cultured in a promyelocytic (HL-60) cell line. In response to microbes, polymorphonuclear leukocytes normally activate the NADPH oxidase enzyme complex and generate superoxide anion (O2-). However, HL-60 cells infected with HGE bacteria did not produce O2- upon activation with PMA. RT-PCR demonstrated that HGE organisms inhibited mRNA expression of a single component of NADPH oxidase, gp91phox, and FACS analysis showed that plasma membrane-associated gp91phox protein was reduced on the infected cells. Infection with HGE organisms also decreased gp91phox mRNA levels in splenic neutrophils in a murine model of HGE, demonstrating this phenomenon in vivo. Therefore, HGE bacteria repress the respiratory burst by down-regulating gp91phox, the first direct inhibition of NADPH oxidase by a pathogen.
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Affiliation(s)
- R Banerjee
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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Artursson K, Gunnarsson A, Wikström UB, Engvall EO. A serological and clinical follow-up in horses with confirmed equine granulocytic ehrlichiosis. Equine Vet J 1999; 31:473-7. [PMID: 10596927 DOI: 10.1111/j.2042-3306.1999.tb03853.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For diagnosis of equine granulocytic ehrlichiosis (EGE) serological testing of antibodies to Ehrlichia equi is frequently used. An elevated antibody level is often misinterpreted as confirmative of active infection and results in treatment with antibiotics. If only seropositivity is considered as the diagnostic criterium, many horses showing convalescence titres will be treated. This study was undertaken to obtain information about the kinetics of antibodies during the course of infection and, for this purpose, 45 horses with clinical signs of EGE and confirmed ehrlichiaemia were monitored serologically and clinically over time. For a correct handling of cases with suspected EGE, the following results should be helpful: (i) 44% of the horses in the acute ehrlichiaemic stage were found to be serologically positive to E. equi; (ii) all horses showed a rapid increase in antibody titre, reaching maximum value within a month after the ehrlichiaemic stage; (iii) when 8 months had passed, titres had decreased, but 18 of 24 examined horses were still serologically positive; (iv) after 12-15 months most of the horses (n = 10) were serologically negative; and (v) the period required for complete clinical recovery varied from one day up to 6 months after antibiotic treatment.
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Affiliation(s)
- K Artursson
- Department of Bacteriology, The National Veterinary Institute, Uppsala, Sweden
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18
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Wu JM, Whyzmuzis CA, Bertone MG, Zhou BS, Hsieh TC. Quantification of the human granulocytic ehrlichiosis agent based on analysis of rRNA isolated from control and infected HL-60 cells. Biochem Biophys Res Commun 1999; 262:7-13. [PMID: 10448059 DOI: 10.1006/bbrc.1999.1134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human granulocytic ehrlichiosis (HGE) is an emerging vector-borne disease caused by an Ehrlichia species similar or identical to E. equi and E. phagocytophila. Previous studies have shown that the pathogen can be cultivated in vitro in permissive cells such as human promyelocytic HL-60 leukemia cells. The mechanism(s) of its infection and propagation in target cells, however, is not well understood, due in part to lack of a method capable of quantitatively determining the amount of the infectious agent. Although several assays currently exist for the HGE agent, they are mostly qualitative and have a number of limitations. In this report, size differences between prokaryotic and eukaryotic rRNAs are utilized to quantitatively assay the HGE agent in HL-60 cells. By comparing the integrated intensity of agarose gel resolved HGE-specific rRNA in host cells, with identically prepared and analyzed rRNA isolated from known quantities of E. coli (JM 109), it is possible to calculate the E. coli-equivalence of the HGE agent present in HL-60 cells according to the equation: Y (E. coli, in viable cells x 10(8)) = -2.573 + 0.11X (% infection by the HGE agent in HL-60 cells). The method described is reproducible, sensitive, and is not limited by availability of antisera. Furthermore, since the assay has no designer primer and repeated amplification requirements, it can be easily disseminated to and standardized in other laboratories.
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Affiliation(s)
- J M Wu
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595, USA
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19
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Magnarelli LA, Ijdo JW, Anderson JF, Padula SJ, Flavell RA, Fikrig E. Human exposure to a granulocytic Ehrlichia and other tick-borne agents in Connecticut. J Clin Microbiol 1998; 36:2823-7. [PMID: 9738027 PMCID: PMC105071 DOI: 10.1128/jcm.36.10.2823-2827.1998] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Indirect fluorescent-antibody (IFA) staining methods with Ehrlichia equi (MRK or BDS strains) and Western blot analyses containing a human granulocytic ehrlichiosis (HGE) agent (NCH-1 strain) were used to confirm probable human cases of infection in Connecticut during 1995 and 1996. Also included were other tests for Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis (HME), Babesia microti, and Borrelia burgdorferi. Thirty-three (8.8%) of 375 patients who had fever accompanied by marked leukopenia or thrombocytopenia were serologically confirmed as having HGE. Western blot analyses of a subset of positive sera confirmed the results of the IFA staining methods for 15 (78.9%) of 19 seropositive specimens obtained from different persons. There was frequent detection of antibodies to a 44-kDa protein of the HGE agent. Serologic testing also revealed possible cases of Lyme borreliosis (n = 142), babesiosis (n = 41), and HME (n = 21). Forty-seven (26.1%) of 180 patients had antibodies to two or more tick-borne agents. Therefore, when one of these diseases is clinically suspected or diagnosed, clinicians should consider the possibility of other current or past tick-borne infections.
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Affiliation(s)
- L A Magnarelli
- Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06504, USA.
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Chang YF, Novosel V, Dubovi E, Wong SJ, Chu FK, Chang CF, Del Piero F, Shin S, Lein DH. Experimental infection of the human granulocytic ehrlichiosis agent in horses. Vet Parasitol 1998; 78:137-45. [PMID: 9735918 DOI: 10.1016/s0304-4017(98)00133-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human blood collected from two patients from Westchester County, New York with human granulocytic ehrlichia (HGE) infection was inoculated into two ponies. Inoculated ponies developed clinical signs similar to a previous report (Madigan et al., 1995). Histopathological changes involved follicular hyperplasia of lymphoid tissues. HGE DNA was detected by PCR in muscle, fascia, peritoneum, and adrenal gland after the ponies produced a high level of antibodies to HGE. We suggest that HGE may reside in poorly vascularized connective tissues, where the antibodies may have some difficulties to penetrate, resulting in persistent infection. Since HGE and E. equi cause very similar diseases in both humans and horses, they may be the same organism with minor genetic differences.
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Affiliation(s)
- Y F Chang
- Diagnostic Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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21
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Klein MB, Hayes SF, Goodman JL. Monocytic differentiation inhibits infection and granulocytic differentiation potentiates infection by the agent of human granulocytic ehrlichiosis. Infect Immun 1998; 66:3410-5. [PMID: 9632613 PMCID: PMC108360 DOI: 10.1128/iai.66.7.3410-3415.1998] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human granulocytic ehrlichiosis (HGE) is an emerging tick-borne infection with a specific tropism for granulocytes. We previously isolated and cultivated the HGE agent in the promyelocytic leukemia cell line HL-60 and have also demonstrated the susceptibility of both granulocytic and monocytic human marrow progenitors. Circulating monocytes have not been observed to be infected, suggesting that cell susceptibility may be differentiation specific. To evaluate this hypothesis, HL-60 cells were differentiated towards granulocytes (with dimethyl sulfoxide or all-trans retinoic acid) or toward monocytes-macrophages (with 12-O-tetradecanoylphorbol-13-acetate [TPA], gamma interferon, or 1, 25-dihydroxyvitamin D3) and then challenged with HGE. HGE binding, internalization, and proliferation were compared in differentiated and untreated control HL-60 cells by immunofluorescence, electron microscopy, and Giemsa staining. Granulocytic differentiation resulted in a doubling of HGE binding and enhanced infection consistent with the agent's clinical tropism for neutrophils. Granulocytic cells were unable to kill internalized ehrlichiae even after activation induced by N-formyl-Met-Leu-Phe alone or together with tumor necrosis factor alpha. In contrast, monocyte-macrophage differentiation with TPA resulted in complete resistance to infection through at least two distinct mechanisms: (i) reduction in binding and uptake and (ii) killing of any internalized organisms. Diminished binding in TPA-treated cells correlated with their reduced expression of sialyl Lewis x (CD15s), a putative cellular receptor component for HGE. The degree of monocytic differentiation and activation induced (i.e., TPA > gamma interferon > vitamin D3) correlated with resistance to HGE. Thus, HL-60 cells exhibit a striking differentiation-specific susceptibility to HGE. Differentiation-induced changes in bacterial adhesion and killing capacity underlie the tropism of HGE for granulocytic HL-60 cells and, conversely, the resistance of activated macrophages to infection.
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Affiliation(s)
- M B Klein
- Department of Medicine, Division of Infectious Diseases, University of Minnesota, Minneapolis, Minnesota, USA
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Massung RF, Slater K, Owens JH, Nicholson WL, Mather TN, Solberg VB, Olson JG. Nested PCR assay for detection of granulocytic ehrlichiae. J Clin Microbiol 1998; 36:1090-5. [PMID: 9542943 PMCID: PMC104695 DOI: 10.1128/jcm.36.4.1090-1095.1998] [Citation(s) in RCA: 306] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A sensitive and specific nested PCR assay was developed for the detection of granulocytic ehrlichiae. The assay amplifies the 16S rRNA gene and was used to examine acute-phase EDTA-blood and serum samples obtained from seven humans with clinical presentations compatible with human granulocytic ehrlichiosis. Five of the seven suspected cases were positive by the PCR assay using DNA extracted from whole blood as the template, compared with a serologic assay that identified only one positive sample. The PCR assay using DNA extracted from the corresponding serum samples as the template identified three positive samples. The sensitivity of the assay on human samples was examined, and the limit of detection was shown to be fewer than 2 copies of the 16S rRNA gene. The application of the assay to nonhuman samples demonstrated products amplified from template DNA extracted from Ixodes scapularis ticks collected in Rhode Island and from EDTA-blood specimens obtained from white-tailed deer in Maryland. All PCR products were sequenced and identified as specific to granulocytic ehrlichiae. A putative variant granulocytic ehrlichia 16S rRNA gene sequence was detected among products amplified from both the ticks and the deer blood specimens.
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Affiliation(s)
- R F Massung
- National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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