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Puri BK, Preyer R, Lee GS, Schwarzbach A. T Lymphocyte Interferon-gamma Response to Anaplasmataceae-related Major Surface Proteins and Ankyrin A in Fibromyalgia. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:1392-1399. [PMID: 38375844 DOI: 10.2174/0118715273274091231207101522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 02/21/2024]
Abstract
BACKGROUND The aetiology of fibromyalgia is unknown; its symptoms may be related to a T-lymphocyte-mediated response to infectious organisms. OBJECTIVES First, to test the hypothesis that fibromyalgia is associated with increased interferon (IFN)-γ-secreting T-lymphocytes after stimulation with Anaplasmataceae-related major surface proteins (MSPs) and the macromolecular translocation type IV secretion system effector ankyrin repeat domain-containing protein A (AnkA). Second, to ascertain the relationship in fibromyalgia between (i) the IFN-γ-secreting T-lymphocyte response to stimulation with Anaplasmataceae-related MSPs and AnkA, and (ii) co-infection by Borrelia and Yersinia spp., and antinuclear antibodies. METHODS Using a case-control design, patients fulfilling the American College of Rheumatology revised criteria for fibromyalgia, and controls, underwent the following blinded assessments: (i) enzyme- linked immune absorbent spot (ELISpot) IFN-γ release assay of T-lymphocyte reactivity to Anaplasmataceae-related MSPs and AnkA; (ii) ELISpot IFN-γ release assays of T-lymphocyte reactivity to three Borrelia antigens, namely Borrelia burgdorferi full antigen (B31); peptide mix (from Borrelia burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii); and Borrelia burgdorferi lymphocyte function-associated antigen-1; (iii) immunoglobulin (Ig) A assay by enzyme-linked immunosorbent assay (ELISA) of antibodies to Yersinia spp.; (iv) IgG (ELISA) antibodies to Yersinia spp.; (v) serum antinuclear antibodies (immunofluorescence). RESULTS The groups were age- and sex-matched. The mean (standard error) value of IFN-γ release for the fibromyalgia group was 1.52 (0.26), compared with 1.00 (0.22) for the controls. Generalised linear modelling (p<0.001) of IFN-γ release in the fibromyalgia patients showed significant main effects of all three indices of Borrelia infection and of antinuclear antibodies. CONCLUSION Anaplasmataceae may play an aetiological role in fibromyalgia.
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Affiliation(s)
- Basant K Puri
- Faculty of Health and Wellbeing, University of Winchester, Winchester, UK
| | | | - Gary S Lee
- Department of Medicine, University of Southampton, Southampton, UK
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Dahmani M, Zhu JC, Cook JH, Riley SP. Anaphylatoxin signaling activates macrophages to control intracellular Rickettsia proliferation. Microbiol Spectr 2023; 11:e0253823. [PMID: 37855623 PMCID: PMC10714731 DOI: 10.1128/spectrum.02538-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Pathogenic Rickettsia species are extremely dangerous bacteria that grow within the cytoplasm of host mammalian cells. In most cases, these bacteria are able to overpower the host cell and grow within the protected environment of the cytoplasm. However, a dramatic conflict occurs when Rickettsia encounter innate immune cells; the bacteria can "win" by taking over the host, or the bacteria can "lose" if the host cell efficiently fights the infection. This manuscript examines how the immune complement system is able to detect the presence of Rickettsia and alert nearby cells. Byproducts of complement activation called anaphylatoxins are signals that "activate" innate immune cells to mount an aggressive defensive strategy. This study enhances our collective understanding of the innate immune reaction to intracellular bacteria and will contribute to future efforts at controlling these dangerous infections.
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Affiliation(s)
- Mustapha Dahmani
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jinyi C. Zhu
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jack H. Cook
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Sean P. Riley
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
- Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
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Upla PU, Sani B, Hadi NS, Al-Mustapha FY, Shuaibu K. Molecular pathogenesis of Rocky Mountain spotted fever: a brief review. IMC JOURNAL OF MEDICAL SCIENCE 2021. [DOI: 10.55010/imcjms.16.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Rocky Mountain spotted fever (RMSF) is a bacterial infection caused by Rickettsia, a diverse group of small Gram-negative rod-shaped α-proteobacteria, and obligates intracellular pathogens, which are free-living in hosts' cell cytoplasm and are transmitted to humans by arthropod vectors. It is the most acute rickettsial diseases known to human, with significant death rates of over 20–30%. They are distinguished by a strictly intracellular position which has, for long, delayed their comprehensive study. This article attempts primarily to focus on the mechanisms of Rickettsia-host cell interactions and the underlying molecular pathogenesis of RMSF.
IMC J Med Sci 2022; 16(1): 004
*Correspondence: Bashiru Sani, Department of Microbiology, Federal University of Lafia, Nasarawa State, Nigeria. Email: bashmodulus@gmail.com
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Affiliation(s)
- Peter Uteh Upla
- Department of Microbiology, Federal University of Lafia, Nasarawa State, Nigeria
| | - Bashiru Sani
- Department of Microbiology, Federal University of Lafia, Nasarawa State, Nigeria
| | - Naja’atu Shehu Hadi
- Department of Microbiology, Federal University of Lafia, Nasarawa State, Nigeria
| | | | - Kabiru Shuaibu
- Department of Microbiology, Federal University of Lafia, Nasarawa State, Nigeria
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Pérez JE, Estrada GI, Zapata Y, Hidalgo M, Serna CC, Castro DC, González C. Frequency of antibodies and seroconversion against Rickettsia spp in patients consulting health institutions in the department of Caldas, Colombia, 2016-2019. BIOMEDICA : REVISTA DEL INSTITUTO NACIONAL DE SALUD 2021; 41:103-117. [PMID: 34669282 PMCID: PMC8724692 DOI: 10.7705/biomedica.5712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 06/17/2021] [Indexed: 11/21/2022]
Abstract
Introduction: Rickettsioses are zoonotic diseases transmitted by arthropods acting as vectors and reservoirs. Disease symptoms are nonspecific and, therefore, their clinical diagnosis is difficult. Indirect immunofluorescence (IFA) is the gold standard assay for diagnosis. The interest for conducting studies on these pathologies has resurfaced in Colombia since 2001; besides, previous studies have evidenced cases of rickettsiosis in the north of the department of Caldas. Objective: To establish the frequency of antibodies and seroconversion against Rickettsia spp. In patients consulting health institutions in Caldas, Colombia, from 2016 to 2019. Materials and methods: We conducted a quantitative, observational, and descriptive study on a non-probabilistic sample of 175 patients with symptoms compatible with rickettsiosis who consulted in different municipalities of Caldas, Colombia; IFA was performed to detect antibodies in the acute and convalescent phases against Rickettsia rickettsii, Rickettsia typhi, and Rickettsia felis. Results: The average age of the patients was 31 years. The municipalities with the highest proportion of seropositive cases were Belalcázar, Chinchiná, Filadelfia, La Dorada, La Merced, and Manizales; 66% of patients owned pets and 12% reported arthropod bites. The most frequent signs and symptoms were headache (69.7%), arthromyalgia (60%), and fever (58.2%). IgG seroprevalence was 60% for R. rickettsii, 47.9% for R. typhi, and, and 24% for R. felis. Eight patients presented seroconversion. Conclusion: We found evidence of the circulation of Rickettsia species from the spotted fever group and the typhus group associated with human cases in Caldas.
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Affiliation(s)
- Jorge Enrique Pérez
- Grupo de Investigación Biosalud, Universidad de Caldas, Manizales, Colombia.
| | - Gloria Inés Estrada
- Facultad de Ciencias para la Salud, Universidad Católica de Manizales, Manizales, Colombia.
| | - Yuliana Zapata
- Facultad de Ciencias para la Salud, Universidad Católica de Manizales, Manizales, Colombia.
| | - Marylin Hidalgo
- Grupo de Enfermedades Infecciosas, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia.
| | - Cristian Camilo Serna
- Grupo de Investigación Gebiome, Programa de Biología, Universidad de Caldas, Manizales, Colombia.
| | - Diego Camilo Castro
- Departamento de Ciencias Básicas, Universidad de Caldas, Manizales, Colombia.
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Ye G, Yang L, Xu L, Pan Z, Dong Z. Neurological presentations caused by Rickettsia felis infection. Br J Hosp Med (Lond) 2021; 82:1-2. [PMID: 34191568 DOI: 10.12968/hmed.2021.0212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gongjie Ye
- Department of Intensive Care, Ningbo Medical Center Lihuili Hospital, Ningbo University, Ningbo, China
| | - Lei Yang
- Department of Intensive Care, Ningbo Medical Center Lihuili Hospital, Ningbo University, Ningbo, China
| | - Li Xu
- Operating Room, Anhui Province Taihe County People's Hospital, Taihe, China
| | - Zhentao Pan
- Department of Intensive Care, Ningbo Medical Center Lihuili Hospital, Ningbo University, Ningbo, China
| | - Zhouzhou Dong
- Department of Intensive Care, Ningbo Medical Center Lihuili Hospital, Ningbo University, Ningbo, China
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Stokes JV, Walker DH, Varela-Stokes AS. The guinea pig model for tick-borne spotted fever rickettsioses: A second look. Ticks Tick Borne Dis 2020; 11:101538. [PMID: 32993947 PMCID: PMC7530330 DOI: 10.1016/j.ttbdis.2020.101538] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022]
Abstract
The guinea pig (Cavia porcellus) has an established track record as an animal model, with its utility in rickettsial research documented as early as the turn of the 20th century. From identifying Rickettsia rickettsii as the agent of Rocky Mountain spotted fever and ticks as the natural transmission route to evaluating protective immunity and treatment for tick-borne rickettsiae, guinea pigs have been essential for advances in our understanding of spotted fever rickettsioses (SFR). Tick feeding on guinea pigs is feasible and results in transmission of tick-borne rickettsiae. The resulting infection leads to the recapitulation of SFR as defined by clinical signs that include fever, unthrift, and in the case of transmission by a Rickettsia parkeri-infected Amblyomma maculatum tick, a characteristic eschar at the site of the bite. No other small animal model recapitulates SFR, is large enough to collect multiple blood and skin samples for longitudinal studies, and has an immune system as similar to the human immune system. In the 1980s, the use of the guinea pig was significantly reduced due to advances made to the more reproductively prolific and inexpensive murine model. These advances included the development of genetically modified murine strains, which resulted in the expansion of murine-specific reagents and assays. Still, the advantages of the guinea pig as a model for SFR persist, novel assays are being developed to better monitor guinea pig immune responses, and tools, like CRISPR/Cas9, are now available. These technical advances allow guinea pigs to again contribute to our understanding of SFR. Importantly, returning to the guinea pig model with enhanced tools will enable rickettsial researchers to corroborate and potentially refine results acquired using mice. This minireview summarizes Cavia porcellus as an animal model for human tick-borne rickettsial diseases.
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Affiliation(s)
- John V Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - David H Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Andrea S Varela-Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA.
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Esteves E, Bizzarro B, Costa FB, Ramírez-Hernández A, Peti APF, Cataneo AHD, Wowk PF, Timóteo RP, Labruna MB, Silva Junior PI, Silva CL, Faccioli LH, Fogaça AC, Sorgi CA, Sá-Nunes A. Amblyomma sculptum Salivary PGE 2 Modulates the Dendritic Cell- Rickettsia rickettsii Interactions in vitro and in vivo. Front Immunol 2019; 10:118. [PMID: 30778355 PMCID: PMC6369204 DOI: 10.3389/fimmu.2019.00118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/15/2019] [Indexed: 01/06/2023] Open
Abstract
Amblyomma sculptum is an important vector of Rickettsia rickettsii, causative agent of Rocky Mountain spotted fever and the most lethal tick-borne pathogen affecting humans. To feed on the vertebrate host's blood, A. sculptum secretes a salivary mixture, which may interact with skin resident dendritic cells (DCs) and modulate their function. The present work was aimed at depicting the A. sculptum saliva-host DC network and the biochemical nature of the immunomodulatory component(s) involved in this interface. A. sculptum saliva inhibits the production of inflammatory cytokines by murine DCs stimulated with LPS. The fractionation of the low molecular weight salivary content by reversed-phase chromatography revealed active fractions eluting from 49 to 55% of the acetonitrile gradient. Previous studies suggested that this pattern of elution matches with that observed for prostaglandin E2 (PGE2) and the molecular identity of this lipid mediator was unambiguously confirmed by a new high-resolution mass spectrometry methodology. A productive infection of murine DCs by R. rickettsii was demonstrated for the first time leading to proinflammatory cytokine production that was inhibited by both A. sculptum saliva and PGE2, a result also achieved with human DCs. The adoptive transfer of murine DCs incubated with R. rickettsii followed by treatment with A. sculptum saliva or PGE2 did not change the cytokine profile associated to cellular recall responses while IgG2a-specific antibodies were decreased in the serum of these mice. Together, these findings emphasize the role of PGE2 as a universal immunomodulator of tick saliva. In addition, it contributes to new approaches to explore R. rickettsii-DC interactions both in vitro and in vivo.
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Affiliation(s)
- Eliane Esteves
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Bruna Bizzarro
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Francisco Borges Costa
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | - Alejandro Ramírez-Hernández
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | - Ana Paula Ferranti Peti
- Department of Clinical Analysis, Toxicology and Food Science, School of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | | | - Pryscilla Fanini Wowk
- Laboratory of Molecular Virology, Carlos Chagas Institute, Fundação Oswaldo Cruz, Curitiba, Brazil
| | - Rodolfo Pessato Timóteo
- Institute of Natural and Biological Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil
| | - Marcelo Bahia Labruna
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | - Célio Lopes Silva
- Department of Biochemistry and Immunology, School of Medicine of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Lúcia Helena Faccioli
- Department of Clinical Analysis, Toxicology and Food Science, School of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Andréa Cristina Fogaça
- Department de Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,National Institute of Science and Technology in Molecular Entomology, National Council of Scientific and Technological Development (INCT-EM/CNPq), Rio de Janeiro, Brazil
| | - Carlos Arterio Sorgi
- Department of Clinical Analysis, Toxicology and Food Science, School of Pharmaceutical Sciences of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Anderson Sá-Nunes
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,National Institute of Science and Technology in Molecular Entomology, National Council of Scientific and Technological Development (INCT-EM/CNPq), Rio de Janeiro, Brazil
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Quiroz-Castañeda RE, Cobaxin-Cárdenas M, Cuervo-Soto LI. Exploring the diversity, infectivity and metabolomic landscape of Rickettsial infections for developing novel therapeutic intervention strategies. Cytokine 2018; 112:63-74. [PMID: 30072088 DOI: 10.1016/j.cyto.2018.07.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 12/25/2022]
Abstract
Rickettsioses are zoonotic infections caused by obligate intracellular bacteria of the genera Rickettsia that affect human health; sometimes humans being considered as accidental hosts. At a molecular level, the rickettsiae infection triggers molecular signaling leading to the secretion of proinflammatory cytokines. These cytokines direct the immune response to the host cell damage and pathogen removal. In this review, we present metabolic aspects of the host cell in the presence of rickettsiae and how this presence triggers an inflammatory response to cope with the pathogen. We also reviewed the secretion of cytokines that modulates host cell response at immune and metabolic levels.
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Affiliation(s)
- Rosa Estela Quiroz-Castañeda
- Unidad de Anaplasmosis, Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria, (CENID-PAVET, INIFAP), Carretera Federal Cuernavaca Cuautla 8534, Progreso, 62574 Jiutepec, Morelos, Mexico.
| | - Mayra Cobaxin-Cárdenas
- Unidad de Anaplasmosis, Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria, (CENID-PAVET, INIFAP), Carretera Federal Cuernavaca Cuautla 8534, Progreso, 62574 Jiutepec, Morelos, Mexico.
| | - Laura Inés Cuervo-Soto
- Facultad de Ciencias, Departamento de Biología, Universidad Antonio Nariño, Sede Circunvalar Carrera 3 Este, No. 47 A15, Bogotá, Colombia
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Oliveira Neto M, Santos H, Fraga R, Pacheco A, Sampaio G, Moura-Costa L, Meyer R, Silva MC, Trindade S, Vale V. Nitric oxide and immune response in infection control of Caseous Lymphadenitis. ARQ BRAS MED VET ZOO 2017. [DOI: 10.1590/1678-4162-9023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT This study aimed to evaluate aspects of host immune response using an experimental infection model of Corynebacterium pseudotuberculosis (CP) in C57/Black6 wild-type and knockout for nitric oxide (KO-NO) mice. 28 mice were evaluated: 4 wild-type controls; 10 wild-type infected with CP; 4 KO-NO controls; 10 KO-NO infected with CP. Infection procedures were carried out by intraperitoneal inoculation using 107. Infected C57/Black6 KO-NO mice began to die after the 5° day post-inoculation, up until the 14º day. Neutrophils were found in increased numbers in the infiltrate of KO-NO murine peritoneal cavities. Examination of splenic tissue revealed an accumulation of lymphocytes, predominantly CD8 T-cells, in experimental animal groups. KO-NO animals were found to have a predominance of granulomas 7 days post-inoculation, primarily in the lymph nodes. In addition, greater amounts of bacteria were recovered from the mesenteric lymph nodes of KO-NO mice. There was no statistically significant difference in the levels of total IgG and its subclasses 14 days post-inoculation between KO-NO and wild groups. The results suggest the importance of nitric oxide in the process of controlling CP infection, as KO-NO animals were observed to be markedly more affected by infection with this bacterium.
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Affiliation(s)
| | | | | | | | | | | | - R. Meyer
- Universidade Federal da Bahia, Brazil
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Kousios A. Does complement Factor H-Related protein 5 Nephropathy (Troodos Nephropathy) protect from rickettsial infections? Med Hypotheses 2017; 98:76-80. [DOI: 10.1016/j.mehy.2016.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
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Papp S, Moderzynski K, Rauch J, Heine L, Kuehl S, Richardt U, Mueller H, Fleischer B, Osterloh A. Liver Necrosis and Lethal Systemic Inflammation in a Murine Model of Rickettsia typhi Infection: Role of Neutrophils, Macrophages and NK Cells. PLoS Negl Trop Dis 2016; 10:e0004935. [PMID: 27548618 PMCID: PMC4993389 DOI: 10.1371/journal.pntd.0004935] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/31/2016] [Indexed: 12/31/2022] Open
Abstract
Rickettsia (R.) typhi is the causative agent of endemic typhus, an emerging febrile disease that is associated with complications such as pneumonia, encephalitis and liver dysfunction. To elucidate how innate immune mechanisms contribute to defense and pathology we here analyzed R. typhi infection of CB17 SCID mice that are congenic to BALB/c mice but lack adaptive immunity. CB17 SCID mice succumbed to R. typhi infection within 21 days and showed high bacterial load in spleen, brain, lung, and liver. Most evident pathological changes in R. typhi-infected CB17 SCID mice were massive liver necrosis and splenomegaly due to the disproportionate accumulation of neutrophils and macrophages (MΦ). Both neutrophils and MΦ infiltrated the liver and harbored R. typhi. Both cell populations expressed iNOS and produced reactive oxygen species (ROS) and, thus, exhibited an inflammatory and bactericidal phenotype. Surprisingly, depletion of neutrophils completely prevented liver necrosis but neither altered bacterial load nor protected CB17 SCID mice from death. Furthermore, the absence of neutrophils had no impact on the overwhelming systemic inflammatory response in these mice. This response was predominantly driven by activated MΦ and NK cells both of which expressed IFNγ and is considered as the reason of death. Finally, we observed that iNOS expression by MΦ and neutrophils did not correlate with R. typhi uptake in vivo. Moreover, we demonstrate that MΦ hardly respond to R. typhi in vitro. These findings indicate that R. typhi enters MΦ and also neutrophils unrecognized and that activation of these cells is mediated by other mechanisms in the context of tissue damage in vivo.
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Affiliation(s)
- Stefanie Papp
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Kristin Moderzynski
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Rauch
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Liza Heine
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Svenja Kuehl
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Heidelinde Mueller
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Bernhard Fleischer
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Institute for Immunology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anke Osterloh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Baltadzhiev IG, Pavlov PI. T-Lymphocyte Subset Absolute Counts in the Peripheral Blood of Mediterranean Spotted Fever Patients: Relations to Disease Severity. Folia Med (Plovdiv) 2016; 57:93-103. [PMID: 26933778 DOI: 10.1515/folmed-2015-0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 02/18/2015] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Mediterranean spotted fever (MSF) in Bulgaria is caused by Rickettsia conorii conorii. AIM This study aims at investigating the absolute counts of T-lymphocyte subsets in the peripheral blood of patients with MSF in order to establish relationships with disease severity. MATERIALS AND METHODS The absolute counts of T-lymphocyte subsets were tested in the blood of 62 patients in the acute stage of MSF. They were assigned into three age and sex matched groups, based on the severity of disease - with mild, moderate or severe forms. Controls were 32 age and sex matched healthy individuals. The diagnosis was confirmed by an immunofluorescence assay. Immunophenotyping was performed using Epics XL-MCL Coulter, USA flow-cytometer. RESULTS The absolute counts of immune competent (CD3+) cells, as well as the counts of helper/inducer (CD3+ CD4+) and suppressor/ cytotoxic (CD3+ CD8+) T-cell subsets decreased in parallel with disease severity. Naïve (CD4+ CD45RA+) and activated memory (CD4+ CD45RO+) T-cell subsets were reduced, particularly in severe MSF. Taken as a whole, the counts of activated (CD3+ HLA-DR+) and that of presenting accessory (CD28+) or stimulatory (CD38+) molecules Т-cell subsets was increased, but in the first two subsets the trend from mild to severe forms of the disease was descending. CONCLUSION Reduced T-lymphocyte subset counts are likely related to trans-migration into perivascular inflammatory foci. The increased number of T-lymphocytes bearing activation molecules reflects a mobilization of the cell-mediated immune response. An important issue of this study is the possible prognostic value of T-cell subsets counting, predicting the evolution of a clinical condition to clinical forms, according to the disease severity.
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Affiliation(s)
| | - Pavel I Pavlov
- Department of Clinical Laboratory, Faculty of Pharmacy, St. George University Hospital, Medical University, Plovdiv, Bulgaria
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Persisting Rickettsia typhi Causes Fatal Central Nervous System Inflammation. Infect Immun 2016; 84:1615-1632. [PMID: 26975992 DOI: 10.1128/iai.00034-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/06/2016] [Indexed: 01/03/2023] Open
Abstract
Rickettsioses are emerging febrile diseases caused by obligate intracellular bacteria belonging to the family Rickettsiaceae. Rickettsia typhi belongs to the typhus group (TG) of this family and is the causative agent of endemic typhus, a disease that can be fatal. In the present study, we analyzed the course of R. typhi infection in C57BL/6 RAG1(-/-) mice. Although these mice lack adaptive immunity, they developed only mild and temporary symptoms of disease and survived R. typhi infection for a long period of time. To our surprise, 3 to 4 months after infection, C57BL/6 RAG1(-/-) mice suddenly developed lethal neurological disorders. Analysis of these mice at the time of death revealed high bacterial loads, predominantly in the brain. This was accompanied by a massive expansion of microglia and by neuronal cell death. Furthermore, high numbers of infiltrating CD11b(+) macrophages were detectable in the brain. In contrast to the microglia, these cells harbored R. typhi and showed an inflammatory phenotype, as indicated by inducible nitric oxide synthase (iNOS) expression, which was not observed in the periphery. Having shown that R. typhi persists in immunocompromised mice, we finally asked whether the bacteria are also able to persist in resistant C57BL/6 and BALB/c wild-type mice. Indeed, R. typhi could be recultivated from lung, spleen, and brain tissues from both strains even up to 1 year after infection. This is the first report demonstrating persistence and reappearance of R. typhi, mainly restricted to the central nervous system in immunocompromised mice.
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Sahni SK, Narra HP, Sahni A, Walker DH. Recent molecular insights into rickettsial pathogenesis and immunity. Future Microbiol 2014; 8:1265-88. [PMID: 24059918 DOI: 10.2217/fmb.13.102] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human infections with arthropod-borne Rickettsia species remain a major global health issue, causing significant morbidity and mortality. Epidemic typhus due to Rickettsia prowazekii has an established reputation as the 'scourge of armies', and as a major determinant of significant 'historical turning points'. No suitable vaccines for human use are currently available to prevent rickettsial diseases. The unique lifestyle features of rickettsiae include obligate intracellular parasitism, intracytoplasmic niche within the host cell, predilection for infection of microvascular endothelium in mammalian hosts, association with arthropods and the tendency for genomic reduction. The fundamental research in the field of Rickettsiology has witnessed significant recent progress in the areas of pathogen adhesion/invasion and host immune responses, as well as the genomics, proteomics, metabolomics, phylogenetics, motility and molecular manipulation of important rickettsial pathogens. The focus of this review article is to capture a snapshot of the latest developments pertaining to the mechanisms of rickettsial pathogenesis and immunity.
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Affiliation(s)
- Sanjeev K Sahni
- Department of Pathology & Institute for Human Infections & Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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Dual mechanisms of metabolite acquisition by the obligate intracytosolic pathogen Rickettsia prowazekii reveal novel aspects of triose phosphate transport. J Bacteriol 2013; 195:3752-60. [PMID: 23772074 DOI: 10.1128/jb.00404-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rickettsia prowazekii is an obligate intracytosolic pathogen and the causative agent of epidemic typhus fever in humans. As an evolutionary model of intracellular pathogenesis, rickettsiae are notorious for their use of transport systems that parasitize eukaryotic host cell biochemical pathways. Rickettsial transport systems for substrates found only in eukaryotic cell cytoplasm are uncommon among free-living microorganisms and often possess distinctive mechanisms. We previously reported that R. prowazekii acquires triose phosphates for phospholipid biosynthesis via the coordinated activities of a novel dihydroxyacetone phosphate transport system and an sn-glycerol-3-phosphate dehydrogenase (K. M. Frohlich et al., J. Bacteriol. 192:4281-4288, 2010). In the present study, we have determined that R. prowazekii utilizes a second, independent triose phosphate acquisition pathway whereby sn-glycerol-3-phosphate is directly transported and incorporated into phospholipids. Herein we describe the sn-glycerol-3-phosphate and dihydroxyacetone phosphate transport systems in isolated R. prowazekii with respect to kinetics, energy coupling, transport mechanisms, and substrate specificity. These data suggest the existence of multiple rickettsial triose phosphate transport systems. Furthermore, the R. prowazekii dihydroxyacetone phosphate transport systems displayed unexpected mechanistic properties compared to well-characterized triose phosphate transport systems from plant plastids. Questions regarding possible roles for dual-substrate acquisition pathways as metabolic virulence factors in the context of a pathogen undergoing reductive evolution are discussed.
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Abstract
Rocky Mountain spotted fever is typically undifferentiated from many other infections in the first few days of illness. Treatment should not be delayed pending confirmation of infection when Rocky Mountain spotted fever is suspected. Doxycycline is the drug of choice even for infants and children less than 8 years old.
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Abstract
Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic, and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group (SFG) and typhus group (TG) rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism toward cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and non-pathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and non-pathogenic species of SFG rickettsiae (SFGR) in mammalian cells. The growth of non-pathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of non-pathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the non-pathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review.
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Affiliation(s)
- Tsuneo Uchiyama
- Department of Microbiology, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan
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Fang R, Ismail N, Walker DH. Contribution of NK cells to the innate phase of host protection against an intracellular bacterium targeting systemic endothelium. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:185-95. [PMID: 22617213 DOI: 10.1016/j.ajpath.2012.03.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 02/10/2012] [Accepted: 03/22/2012] [Indexed: 11/19/2022]
Abstract
We investigated the mechanisms by which natural killer (NK) cells mediate innate host defense against infection with an endothelium-targeting intracellular bacterium, Rickettsia. We found that a robust Rickettsia-induced innate response in resistant mice cleared the bacteria early in the infection and was associated with significantly higher frequencies of splenic interferon (IFN)-γ (+) CD8(+) T cells and cytotoxic NK cells compared with susceptible mice. More importantly, NK cell-deficient Rag(-/-)γc(-/-) animals displayed significantly increased susceptibility to Rickettsia infection compared with NK cell-sufficient Rag(-/-) mice, as evidenced by impaired bacterial clearance, early development of severe thrombosis in the liver, and a decreased serum level of IFN-γ. Furthermore, the lack of NK cells also impaired host resistance of CB-17 scid mice to Rickettsia, similar to what was observed in Rag(-/-)γc(-/-) mice. Interestingly, perforin deficiency in Rag(-/-)Prf1(-/-) mice resulted in greater thrombosis and insignificantly different systemic levels of IFN-γ compared with Rag(-/-) mice, suggesting that perforin, which is mainly produced by NK cells, is involved in the prevention of vascular damage. Together, these findings reveal that NK cells mediate the innate phase of host protection against infection with rickettsiae, most likely via IFN-γ production. Furthermore, NK cells are involved in preventing rickettsial infection-induced endothelial cell damage, possibly via perforin production.
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Affiliation(s)
- Rong Fang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Kularatne SAM, Weerakoon KGAD, Rajapakse RPVJ, Madagedara SC, Nanayakkara D, Premaratna R. A case series of spotted fever rickettsiosis with neurological manifestations in Sri Lanka. Int J Infect Dis 2012; 16:e514-7. [PMID: 22541336 DOI: 10.1016/j.ijid.2012.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 02/05/2012] [Accepted: 02/28/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Spotted fever group (SFG) rickettsial infections are increasingly detected in Sri Lanka. We describe 17 patients with SFG who developed neurological manifestations. METHODS The cases were studied prospectively from 2008 at the Teaching Hospital, Peradeniya. An immunofluorescent antibody assay (IFA) was used to confirm the diagnosis. RESULTS All had an IFA IgG titer ranging from 1/64 to 1/4096 and a positive IFA IgM titer against Rickettsia conorii antigen; in 10 (59%) cases the IgG titers were ≥ 1/256 (definitive cases). The median age of the patients was 62 years (range 26-82 years); 10 were male and seven female. The median duration of fever was 12 days (range 4-35 days). Neurological manifestations on admission were drowsiness or confusion in 14 (82%) and a semi-comatose state in three (18%). Rigidity of the limbs occurred in 14 (82%), bradykinesia and resting tremors in 12 (71%), which persisted after defervescence, neck stiffness in seven (42%), weakness of the limbs in five (29%), deafness in two (12%), and stupor in three (18%). Electroencephalograms in three (18%) showed generalized slow waves. Cerebrospinal fluid examination showed a cellular reaction, predominantly lymphocytes, in three cases. Two patients died (fatality rate 12%). CONCLUSION We have documented for the first time the neurological features of SFG rickettsioses in the Central Province, Sri Lanka. These were predominantly extrapyramidal features in patients of older age.
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Affiliation(s)
- S A M Kularatne
- Department of Medicine, Faculty of Medicine, University of Peradeniya, Kandy, Sri Lanka
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Duan C, Meng Y, Wang X, Xiong X, Wen B. Exploratory study on pathogenesis of far-eastern spotted fever. Am J Trop Med Hyg 2011; 85:504-9. [PMID: 21896812 DOI: 10.4269/ajtmh.2011.10-0660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Far-eastern spotted fever is an emerging disease caused by Rickettsia heilongjiangensis, a tick-borne obligate intracellular bacterium. In this study, R. heilongjiangensis was used to infect BALB/c mice by inoculation of retro-orbital venous plexus to imitate a blood infection caused by tick biting. We found that R. heilongjiangensis rapidly entered the circulation for systemic dissemination and the pathogen existed in liver, spleen, lungs, and brain of the mice at least 9 days post-infection (p.i.). Severe pathological lesions were observed in liver, lungs, and brain at Day 6 p.i. In addition, the elevated levels of inflammatory cytokines, including interferon-γ, tumor necrosis factor, and CC chemokine, were detected in the infected organs at Day 3 p.i. Our results reveal that R. heilongjiangensis may cause an infection in BALB/c mice and the pathological lesions in the infected mice are associated with host inflammatory response induced by R. heilongjiangensis.
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Affiliation(s)
- Changsong Duan
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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Abstract
One century after the first description of rickettsiae as human pathogens, the rickettsiosis remained poorly understood diseases. These microorganisms are indeed characterized by a strictly intracellular location which has, for long, prohibited their detailed study. Within the last ten years, the completion of the genome sequences of several strains allowed gaining a better knowledge about the molecular mechanisms involved in rickettsia pathogenicity. Here, we summarized available data concerning the critical steps of rickettsia-host cell interactions that should contribute to tissue injury and diseases, that is, adhesion, phagosomal escape, motility, and intracellular survival of the bacteria.
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Affiliation(s)
- Premanand Balraj
- Unité des Rickettsies, URMITE IRD-CNRS 6236, Faculté de Médecine, Marseille, France
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Relevance of gamma interferon, tumor necrosis factor alpha, and interleukin-10 gene polymorphisms to susceptibility to Mediterranean spotted fever. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:811-5. [PMID: 19386798 DOI: 10.1128/cvi.00121-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The acute phase of Mediterranean spotted fever (MSF) is characterized by dramatic changes in cytokine production patterns, clearly indicating their role in the immunomodulation of the response against the microorganism, and the differences in cytokine production seem to influence the extent and severity of the disease. In this study, the single nucleotide polymorphisms (SNPs) of tumor necrosis factor alpha (TNF-alpha) -308G/A (rs1800629) and interleukin-10 (IL-10) -1087G/A (rs1800896), -824C/T (rs1800871), and -597C/A (rs1800872) and the gamma interferon (IFN-gamma) T/A SNP at position +874 (rs2430561) were typed in 80 Sicilian patients affected by MSF and in 288 control subjects matched for age, gender, and geographic origin. No significant differences in TNF-alpha -308G/A genotype frequencies were observed. The +874TT genotype, associated with an increased production of IFN-gamma, was found to be significantly less frequent in MSF patients than in the control group (odds ratio [OR], 0.18; 95% confidence interval [95% CI], 0.06 to 0.51; P corrected for the number of genotypes [Pc], 0.0021). In addition, when evaluating the IFN-gamma and IL-10 genotype interaction, a significant increase of +874AA/-597CA (OR, 5.31; 95% CI, 2.37 to 11.88; P(c), 0.0027) combined genotypes was observed. In conclusion, our data strongly suggest that finely genetically tuned cytokine production may play a crucial role in the regulation of the immune response against rickettsial infection, therefore influencing the disease outcomes, ranging from nonapparent or subclinical condition to overt or fatal disease.
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Bechah Y, Capo C, Mege JL, Raoult D. Rickettsial diseases: from Rickettsia-arthropod relationships to pathophysiology and animal models. Future Microbiol 2008; 3:223-36. [PMID: 18366341 DOI: 10.2217/17460913.3.2.223] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rickettsiae cause spotted fevers and typhus-related diseases in humans. Some of these diseases occur worldwide and are life-threatening, for example, epidemic typhus is still a major health problem despite the apparent efficiency of antibiotic treatment. In addition, Rickettsia prowazekii, the agent of epidemic typhus, and R. rickettsii, the agent of Rocky Mountain spotted fever, are microorganisms that could potentially be used as bioweapons to induce panic in the population. Rickettsiae are obligate intracellular bacteria in both vertebrate and invertebrate hosts, but rickettsial species differ in terms of association with arthropods, behavior of the vector to infection, pathophysiology and outcome of the disease. Understanding the pathogenic steps of rickettsioses is essential to develop protective strategies against these bacteriological threats. Unfortunately, the mechanisms involved in the pathogenesis of many rickettsioses are poorly characterized, and protective immunity is incompletely understood, in part because accurate animal models that mimic human diseases are lacking. In the past, murine models have been of limited value because infection of mice was without effect or resulted in erratic mortality. Recent studies have reported that rickettsial infection can be established in mice, depending on the genetic background of mice, the type of rickettsial species and the route of inoculation. These models may be useful for analyzing the pathogenesis of rickettsioses, especially epidemic typhus, evaluating new therapeutic molecules and vaccine candidates, and preventing future outbreaks.
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Affiliation(s)
- Yassina Bechah
- Unité des Rickettsies, CNRS UMR 6020, Université de la Méditerranée, Faculté de Médecine, 27 Bld. Jean Moulin, 13385 Marseille Cedex 05, France.
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Molecular Pathology of Rickettsial Lung Infections. MOLECULAR PATHOLOGY LIBRARY 2008. [PMCID: PMC7147442 DOI: 10.1007/978-0-387-72430-0_38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rickettsial infections of humans comprise a diverse group of infections caused by pathogens that are obligate intracellular bacteria with a genetic relationship, including the genera Rickettsia, Orientia, Ehrlichia, and Anaplasma. The host cells of these pathogens largely belie the systemic clinical manifestations, because Rickettsia and Orientia infect endothelial cells, and Ehrlichia and Anaplasma infect circulating leukocytes (monocytes and neutrophils, respectively). Thus, the predominant manifestations (fever, headache, myalgia, with or without rash) do not usually focus attention on the respiratory system; however, the underlying pathogenesis of these infections involves degrees of vascular compromise either by direct injury and inflammation or by the action of vasoactive proinflammatory molecules such as cytokines, chemokines, and prostaglandins. Given that the lung possesses the largest vascular bed in the human body, it is not surprising that pulmonary involvement is periodically identified and, when severely affected, is considered a potentially life-threatening complication.1,2
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25
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Woods ME, Olano JP. Host defenses to Rickettsia rickettsii infection contribute to increased microvascular permeability in human cerebral endothelial cells. J Clin Immunol 2007; 28:174-85. [PMID: 17957455 DOI: 10.1007/s10875-007-9140-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2007] [Accepted: 09/19/2007] [Indexed: 12/07/2022]
Abstract
Rickettsiae are arthropod-borne intracellular bacterial pathogens that primarily infect the microvascular endothelium leading to systemic spread of the organisms and the major pathophysiological effect, increased microvascular permeability, and edema in vital organs such as the lung and brain. Much work has been done on mechanisms of immunity to rickettsiae, as well as the responses of endothelial cells to rickettsial invasion. However, to date, no one has described the mechanisms of increased microvascular permeability during acute rickettsiosis. We sought to establish an in vitro model of human endothelial-target rickettsial infection using the etiological agent of Rocky Mountain spotted fever, Rickettsia rickettsii, and human cerebral microvascular endothelial cells. Endothelial cells infected with R. rickettsii exhibited a dose-dependent decrease in trans-endothelial electrical resistance, which translates into increased monolayer permeability. Additionally, we showed that the addition of pro-inflammatory stimuli essential to rickettsial immunity dramatically enhanced this effect. This increase in permeability correlates with dissociation of adherens junctions between endothelial cells and is not dependent on the presence of nitric oxide. Taken together, these results demonstrate for the first time that increased microvascular permeability associated with rickettsial infection is partly attributable to intracellular rickettsiae and partly attributable to the immune defenses that have evolved to protect the host from rickettsial spread.
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Affiliation(s)
- Michael E Woods
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd. Rt 0428, Galveston, TX, USA
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26
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Walker DH. Rickettsiae and Rickettsial Infections: The Current State of Knowledge. Clin Infect Dis 2007; 45 Suppl 1:S39-44. [PMID: 17582568 DOI: 10.1086/518145] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
New human rickettsial pathogens have been discovered, and long-known rickettsiae of undetermined pathogenicity have been demonstrated to cause illness. Disease associated with Rickettsia slovaca has unique clinical manifestations, including prominent lymphadenopathy without fever and rash. Rickettsial genomes are highly conserved, with reductive evolution leading to a small genome that relies on the host cell for many biosynthetic functions. Advances in the evaluation of the pathogenesis of rickettsial disease include identification of rickettsial adhesins, a host cell receptor, signaling elements associated with entry of rickettsiae by induced phagocytosis, rickettsial enzymes mediating phagosomal escape, and host actin-based rickettsial cell-to-cell spread. Disruption of adherens junctions of infected endothelial cells likely plays a role in the critical pathophysiologic mechanism: increased microvascular permeability. Production of reactive oxygen species by infected endothelium injures these cells. However, disseminated intravascular coagulation rarely occurs. Immunity is mediated by reactive cytokine-activated rickettsicidal nitrogen and oxygen species and by clearance of rickettsiae by cytotoxic CD8 T cells.
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Affiliation(s)
- David H Walker
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609, USA.
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Bechah Y, Capo C, Grau GE, Raoult D, Mege JL. A murine model of infection with Rickettsia prowazekii: implications for pathogenesis of epidemic typhus. Microbes Infect 2007; 9:898-906. [PMID: 17537665 DOI: 10.1016/j.micinf.2007.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 03/13/2007] [Accepted: 03/14/2007] [Indexed: 10/23/2022]
Abstract
Epidemic typhus remains a major disease threat, furthermore, its etiologic agent, Rickettsia prowazekii, is classified as a bioterrorism agent. We describe here a murine model of epidemic typhus that reproduced some features of the human disease. When BALB/c mice were inoculated intravenously with R. prowazekii (Breinl strain), they survived but did not clear R. prowazekii infection. Immunohistological analysis of tissues and quantitative PCR showed that R. prowazekii was present in blood, liver, lungs and brain 1 day after infection and persisted for at least 9 days. Importantly, infected mice developed interstitial pneumonia, with consolidation of the alveoli, hemorrhages in lungs, multifocal granulomas in liver, and hemorrhages in brain, as seen in humans. Circulating antibodies directed against R. prowazekii were detected at day 4 post-infection and steadily increased for up to 21 days, demonstrating that R. prowazekii lesions were independent of humoral immune response. R. prowazekii-induced lesions were associated with inflammatory response, as demonstrated by elevated levels of inflammatory cytokines including interferon-gamma, tumor necrosis factor and the CC chemokine RANTES in the lesions. We concluded that the BALB/c mouse strain provides a useful model for studying the pathogenic mechanisms of epidemic typhus and its control by the immune system.
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Affiliation(s)
- Yassina Bechah
- Unité des Rickettsies, CNRS UMR 6020, Université de la Méditerranée, Faculté de Médecine, 27 Bld. J. Moulin, 13385 Marseille Cedex 05, France
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Dierberg KL, Dumler JS. Lymph node hemophagocytosis in rickettsial diseases: a pathogenetic role for CD8 T lymphocytes in human monocytic ehrlichiosis (HME)? BMC Infect Dis 2006; 6:121. [PMID: 16859547 PMCID: PMC1559625 DOI: 10.1186/1471-2334-6-121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 07/21/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human monocytic ehrlichiosis (HME) and Rocky Mountain spotted fever (RMSF) are caused by Ehrlichia chaffeensis and Rickettsia rickettsii, respectively. The pathogenesis of RMSF relates to rickettsia-mediated vascular injury, but it is unclear in HME. METHODS To study histopathologic responses in the lymphatic system for correlates of immune injury, lymph nodes from patients with HME (n = 6) and RMSF (n = 5) were examined. H&E-stained lymph node tissues were examined for five histopathologic features, including hemophagocytosis, cellularity, necrosis, and vascular congestion and edema. The relative proportions of CD68 macrophages, CD8 and CD4 T lymphocytes, and CD20 B lymphocytes were evaluated by immunohistochemical staining. RESULTS Hemophagocytosis was similar in HME and RMSF, and was greater than in control cases (p = .015). Cellularity in HME was not different from controls, whereas RMSF lymph nodes were markedly less cellular (p < 0.002). E. chaffeensis-infected mononuclear phagocytes were infrequent compared to R. rickettsii-infected endothelial cells. More CD8 cells in lymph nodes were observed with HME (p < .001), but no quantitative differences in CD4 lymphocytes, macrophages, or B lymphocytes were identified. CONCLUSION Hemophagocytosis, CD8 T cell expansion, and the paucity of infected cells in HME, suggest that E. chaffeensis infection leads to macrophage activation and immune-mediated injury.
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Affiliation(s)
- Kerry L Dierberg
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - J Stephen Dumler
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Maxwell SS, Stoklasek TA, Dash Y, Macaluso KR, Wikel SK. Tick modulation of the in-vitro expression of adhesion molecules by skin-derived endothelial cells. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2006; 99:661-72. [PMID: 16212800 DOI: 10.1179/136485905x51490] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
As a tick feeds, its saliva induces innate and acquired immune responses in the host, including leucocyte infiltration into the bite site. Tick salivary glands produce molecules, however, that counteract many host defences against blood feeding. The effects of salivary-gland extracts (SGE) of Dermacentor andersoni and Ixodes scapularis on the expression of various adhesion molecules [E-selectin, P-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1)] by the sEND.1 cell line (which is based on cells from the subcutaneous tissue of mice) have now been investigated in vitro. The effects were found to differ with the tick species. The SGE of D. andersoni significantly down-regulated the expression of ICAM-1, whereas a similar extract prepared from I. scapularis significantly reduced the expression of P-selectin and VCAM-1. Tick salivary proteins therefore appear to have direct effects on adhesion-molecule expression, in addition to their previously established roles in down-regulating the pro-inflammatory cytokines that activate endothelial cells. It remains unclear exactly how the reduction of adhesion-molecule expression in the host's endothelial cells benefits the feeding tick but it may alter leucocyte migration to the bite site and/or reduce antigen presentation by the endothelial cells. It may also modulate the interactions between the host's leucocytes and any tick-borne pathogens, during initial infection of the endothelium.
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Affiliation(s)
- S S Maxwell
- Center for Microbial Pathogenesis, School of Medicine, University of Connecticut Health Center, 263 Farmington Avenue, MC-3710, Farmington, CT 06030, USA
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Renesto P, Samson L, Ogata H, Azza S, Fourquet P, Gorvel JP, Heinzen RA, Raoult D. Identification of two putative rickettsial adhesins by proteomic analysis. Res Microbiol 2006; 157:605-12. [PMID: 16574381 DOI: 10.1016/j.resmic.2006.02.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 02/07/2006] [Accepted: 02/07/2006] [Indexed: 10/25/2022]
Abstract
The rickettsial membrane proteins that promote their uptake by eukaryotic host cells are unknown. To identify rickettsial ligand(s) that bind host cell surface proteins, biotinylated epithelial cells were used to probe a nitrocellulose membrane containing rickettsial extracts separated by SDS-PAGE. This overlay assay revealed that two close rickettsial ligands of approximately 32-30 kDa were recognized by host cells. Both proteins were identified using high resolution 2D-PAGE coupled with mass spectrometry analysis. One protein was identified as the C-terminal extremity of rOmpB called the beta-peptide. The second interacting protein was identified as a protein of unknown function encoded by RC1281 and RP828 in Rickettsia conorii and in Rickettsia prowazekii, respectively, that shares strong similarities with other bacterial adhesins. Both proteins are highly conserved within the Rickettsia genus and might play a critical role in their pathogenicity. These data may have important implications for the development of future vaccines against rickettsial infections.
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Affiliation(s)
- Patricia Renesto
- Unité des Rickettsies, CNRS UMR 6020, IFR-48, Faculté de Médecine, 27 Boulevard Jean Moulin, 13385 Marseille, France.
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Wu JJ, Huang DB, Pang KR, Tyring SK. Rickettsial infections around the world, part 1: pathophysiology and the spotted fever group. J Cutan Med Surg 2006; 9:54-62. [PMID: 16392014 DOI: 10.1007/s10227-005-0133-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND The rickettsial diseases are an important group of infectious agents that have dermatological manifestations. These diseases are important to consider in endemic areas, but in certain suspicious cases, possible acts of bioterrorism should warrant prompt notification of the appropriate authorities. OBJECTIVE In this two part review article, we review these diverse diseases by examining established and up-to-date information about the pathophysiology, epidemiology, clinical manifestations, and treatment of the ricksettsiae. METHODS Using PubMed to search for relevant articles, we browsed over 500 articles to compose a clinically based review article. RESULTS Part one focuses on pathophysiology of the rickettsial diseases and the clinical aspects of the spotted fever group. CONCLUSIONS At the completion of part one of this learning activity, participants should be able to discuss all of the clinical manifestations and treatments of the sported fever group. Participants should also be familiar with the pathophysiology of the rickettsial diseases.
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Affiliation(s)
- Jashin J Wu
- Department of Dermatology, University of California, Irvine, California, USA
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32
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Abstract
Serum specimens from patients at 4 sites in Peru were tested for evidence of spotted fever group rickettsial infection. Results showed that 30 (18%) of 170 patients had spotted fever group rickettsial infections, which likely caused their illnesses. These findings document laboratory-confirmed spotted fever from diverse areas of Peru.
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Affiliation(s)
- George B. Schoeler
- U.S. Navy Disease Vector Ecology and Control Center, Silverdale, Washington, USA
| | | | - Allen Richards
- U.S. Naval Medical Research Center, Silver Spring, Maryland, USA
| | | | - James G. Olson
- U.S. Naval Medical Research Center Detachment, Lima, Peru
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33
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Wu JJ, Huang DB, Pang KR, Tyring SK. Rickettsial Infections around the World, Part 1: Pathophysiology and the Spotted Fever Group. J Cutan Med Surg 2005. [DOI: 10.1177/120347540500900203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: The rickettsial diseases are an important group of infectious agents that have dermatological manifestations. These diseases are important to consider in endemic areas, but in certain suspicious cases, possible acts of bioterrorism should warrant prompt notification of the appropriate authorities. Objective: In this two part review article, we review these diverse diseases by examining established and up-to-date information about the pathophysiology, epidemiology, clinical manifestations, and treatment of the ricksettsiae. Methods: Using PubMed to search for relevant articles, we browsed over 500 articles to compose a clinically based review article. Results: Part one focuses on pathophysiology of the rickettsial diseases and the clinical aspects of the spotted fever group. Conclusions: At the completion of part one of this learning activity, participants should be able to discuss all of the clinical manifestations and treatments of the sported fever group. Participants should also be familiar with the pathophysiology of the rickettsial diseases.
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Affiliation(s)
- Jashin J. Wu
- Department of Dermatology, University of California, Irvine, California, USA
| | - David B. Huang
- Division of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
- Division of Infectious Diseases, Department of Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Katie R. Pang
- Department of Dermatology, Wayne State University School of Medicine, Detroit, Michigan, Texas, USA
| | - Stephen K. Tyring
- Department of Dermatology, University of Texas Health Science Center, Houstan, Texas, USA
- Center for Clinical Studies, Houston, Texas, USA
- Center for Clinical Studies, 2060 Space Park Drive, Suite 200, Houston, TX, 77058, USA
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34
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Abstract
Human infections by intracellular bacteria have been recognized for many years, but much of what we know about the pathogenesis of these diseases and their etiologic organisms has emerged within the past few years as a result of improved molecular-based means for their detection and classification. New insights concerning the epidemiology and pathogenesis of intracellular bacterial infections and methods for the detection of Chlamydophila pneumoniae, Ehrlichia chaffeensis, Anaplasma phagocytophilum, and Rickettsia species have made an impact on how we view them as agents of human disease. Emerging evidence suggesting a possible intracellular existence for another organism, Mycoplasma pneumoniae, may explain how this organism interacts with the host to induce chronic inflammatory conditions of the respiratory tract.
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Affiliation(s)
- Brenda Katz
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35249, USA
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35
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Feng HM, Whitworth T, Popov V, Walker DH. Effect of antibody on the rickettsia-host cell interaction. Infect Immun 2004; 72:3524-30. [PMID: 15155660 PMCID: PMC415703 DOI: 10.1128/iai.72.6.3524-3530.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A recent study demonstrated that polyclonal antibodies to Rickettsia conorii and monoclonal antibodies to outer membrane proteins A (OmpA) and B (OmpB) provided effective, Fc-dependent, passive immunity, even in severe combined immunodeficient mice with an established infection. In order to determine the mechanism of protection, mouse endothelial and macrophage-like cell lines were infected with R. conorii that had been exposed to polyclonal antibodies, monoclonal antibodies to OmpA or OmpB, Fab fragments of the polyclonal antibodies, or normal serum or that were left untreated. At 0 h, Fc-dependent antibody enhancement of R. conorii adherence to endothelial and macrophage-like cell lines was inhibited by the presence of normal serum, suggesting Fc receptor-mediated adherence of opsonized rickettsiae. At 3 h, the opsonized rickettsiae had been internalized. After 72 h, inhibited survival of rickettsiae exposed to polyclonal antibodies or monoclonal antibodies to OmpA or OmpB was evident compared with growth of untreated and normal serum-treated and polyclonal Fab antibody-treated R. conorii. Polyclonal antibodies and an anti-OmpB monoclonal antibody inhibited the escape of R. conorii from the phagosome, resulting in intraphagolysosomal rickettsial death. At 48 h of infection, rickettsicidal activity of macrophages by opsonized rickettsiae was inhibited by NG-monomethyl-L-arginine, superoxide dismutase, mannitol, or supplemental L-tryptophan, and endothelial rickettsicidal activity against opsonized rickettsiae was inhibited by NG-monomethyl-L-arginine, superoxide dismutase, catalase, or supplemental L-tryptophan. Thus, Fc-dependent antibodies protected against R. conorii infection of endothelium and macrophages by opsonization that inhibited phagosomal escape and resulted in phagolysosomal killing mediated by nitric oxide, reactive oxygen intermediates, and L-tryptophan starvation.
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Affiliation(s)
- Hui-Min Feng
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA
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36
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Bolaños M, Angel-Moreno A, Pérez-Arellano JL. [Murine typhus. A disease to think about here and now]. Med Clin (Barc) 2004; 122:383-9. [PMID: 15033045 DOI: 10.1016/s0025-7753(04)74250-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Margarita Bolaños
- Servicio de Microbiología, Hospital Universitario Insular de Gran Canaria, Gran Canaria, Spain
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37
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Rydkina E, Sahni SK, Santucci LA, Turpin LC, Baggs RB, Silverman DJ. Selective modulation of antioxidant enzyme activities in host tissues during Rickettsia conorii infection. Microb Pathog 2004; 36:293-301. [PMID: 15120155 DOI: 10.1016/j.micpath.2004.01.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 01/19/2004] [Accepted: 01/21/2004] [Indexed: 10/26/2022]
Abstract
The involvement of oxidative mechanisms in the pathogenesis of rickettsiosis was investigated using infection of C3H/HeN mice with sub-lethal and lethal infectious doses of Rickettsia conorii, the causative agent of Mediterranean spotted fever. Microscopic examination of tissues at 48 and 96 h post-infection revealed characteristic pathologic features and the presence of rickettsiae in the endothelium of infected tissues. Activities of key antioxidant enzymes, namely glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, and superoxide dismutase, at these times exhibited a pattern of differential and selective modulation in brain, lungs, and testes of mice infected with viable organisms, whereas heat-inactivated or sonically disrupted rickettsiae had no effect. Of these, most significant changes were evident in the lungs of infected animals. Adaptive alterations in oxidant-scavenging enzymes occurred in apparent correlation with the dose and duration of infection. Treatment with an antioxidant, alpha-lipoic acid, protected against infection-induced oxidative injury via regulation of antioxidant enzyme activities and maintenance of reduced glutathione levels. These results suggest the involvement of regulatory enzymes of glutathione redox and superoxide scavenging systems in the antioxidant response during in vivo infection, the extent of which varies with the titer of viable rickettsiae in different organs of the host.
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Affiliation(s)
- Elena Rydkina
- Hematology-Oncology Unit, Hemostasis and Thrombosis Program, Department of Medicine, University of Rochester School of Medicine and Dentistry, Box 610, 601 Elmwood Avenue, Rochester, NY 14642, USA
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38
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Feng HM, Whitworth T, Olano JP, Popov VL, Walker DH. Fc-dependent polyclonal antibodies and antibodies to outer membrane proteins A and B, but not to lipopolysaccharide, protect SCID mice against fatal Rickettsia conorii infection. Infect Immun 2004; 72:2222-8. [PMID: 15039346 PMCID: PMC375156 DOI: 10.1128/iai.72.4.2222-2228.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An emphasis on cellular immunity against Rickettsia has led to neglect of analysis of the role of antibody. The availability of an excellent mouse model of spotted fever rickettsiosis enabled investigation of a potential role of antibody in immunity to Rickettsia conorii. C3H severe combined immunodeficiency (SCID) mice were passively transfused with monoclonal antibodies against rickettsial outer membrane protein A (OmpA), OmpB, or lipopolysaccharide (LPS), polyclonal anti-R. conorii serum, Fab fragments of polyclonal antiserum, or no antibodies and then challenged 48 h later with 10 50% lethal doses (LD(50)) of R. conorii. All mice that received monoclonal antibodies against OmpA and two of four mice that received monoclonal antibodies against OmpB or polyclonal antisera were completely protected, but the recipients of anti-LPS antibodies or the Fab fragments were not protected. Polyclonal antibody treatment of C3H SCID mice that had been infected with 10 LD(50) of R. conorii 4 or 5 days earlier prolonged the life of the infected mice from 10.4 to 22.5 days and resulted in decreased levels of infectious rickettsiae in the spleen and liver 24 and 48 h later. Treatment with protective antibodies resulted in the development of large aggregates of R. conorii antigens in splenic macrophages and intraphagolysosomal rickettsial death and digestion. The kinetics of development of antibodies to R. conorii determined by immunoblotting revealed antibodies to LPS on day 6 and antibodies to OmpA and OmpB on day 12, when recovery from the infection had already occurred. Antibodies to particular epitopes of OmpA and OmpB may protect against reinfection, but they may not play a key role in immunity against primary infection. Antibodies might be useful for treating infections with antibiotic-resistant organisms, and some B-cell epitopes should be included in a subunit vaccine.
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MESH Headings
- Animals
- Antibodies, Bacterial/administration & dosage
- Antibodies, Bacterial/blood
- Antibodies, Bacterial/immunology
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/blood
- Antibodies, Monoclonal/immunology
- Bacterial Outer Membrane Proteins/immunology
- Boutonneuse Fever/mortality
- Boutonneuse Fever/prevention & control
- Immunization, Passive
- Lipopolysaccharides/immunology
- Mice
- Mice, Inbred C3H
- Mice, SCID
- Receptors, Fc/metabolism
- Rickettsia conorii/immunology
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Affiliation(s)
- Hui-Min Feng
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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39
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Joshi SG, Francis CW, Silverman DJ, Sahni SK. NF-κB activation suppresses host cell apoptosis duringRickettsia rickettsiiinfection via regulatory effects on intracellular localization or levels of apoptogenic and anti-apoptotic proteins. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09552.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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40
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Li Z, Díaz-Montero CM, Valbuena G, Yu XJ, Olano JP, Feng HM, Walker DH. Identification of CD8 T-lymphocyte epitopes in OmpB of Rickettsia conorii. Infect Immun 2003; 71:3920-6. [PMID: 12819078 PMCID: PMC161984 DOI: 10.1128/iai.71.7.3920-3926.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 1.2-kb DNA fragment of the Rickettsia conorii outer membrane protein B gene (OmpB(451-846)) was subcloned using site-specific PCR primers and expressed as six smaller fragments: OmpB(458-652), OmpB(595-744), OmpB(595-654), OmpB(645-692), OmpB(689-744), and OmpB(739-848). NCTC cells transfected with a mammalian expression vector expressing the fragments OmpB(689-744) and OmpB(739-848) stimulated immune anti-R. conorii CD8 T lymphocytes, suggesting the presence of CD8 T-lymphocyte-stimulating epitopes on these fragments. In order to further characterize the CD8 T-lymphocyte-stimulatory elements, CD8 T-lymphocyte epitopes on OmpB(689-744) and OmpB(739-848) were mapped by overlapping synthetic peptides. The ability of these synthetic peptides to stimulate immune CD8 T lymphocytes was determined by gamma interferon (IFN-gamma) production and cell proliferation after incubation with simian virus 40-transformed murine vascular endothelial cells in the presence of a 20 micro M solution of each synthetic peptide. Five synthetic peptides, SKGVNVDTV (OmpB(708-716)), ANVGSFVFN (OmpB(735-743)), IVSGTVGGQ (OmpB(749-757)), ANSTLQIGG (OmpB(789-797)), and IVEFVNTGP (OmpB(812-820)), induced secretion of IFN-gamma at significantly higher levels than the controls. Three of these five peptides, SKGVNVDTV (OmpB(708-716)), ANSTLQIGG (OmpB(789-797)), and IVEFVNTGP (OmpB(812-820)), also stimulated the proliferation of immune CD8 T lymphocytes. Significantly higher levels of specific cytotoxic T-lymphocyte killing were observed with the same three synthetic peptides, SKGVNVDTV (OmpB(708-716)), ANSTLQIGG (OmpB(789-797)), and IVEFVNTGP (OmpB(812-820)).
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Affiliation(s)
- Zhen Li
- Department of Pathology, WHO Collaborating Center for Tropical Diseases, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0609, USA
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41
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Joshi SG, Francis CW, Silverman DJ, Sahni SK. Nuclear factor kappa B protects against host cell apoptosis during Rickettsia rickettsii infection by inhibiting activation of apical and effector caspases and maintaining mitochondrial integrity. Infect Immun 2003; 71:4127-36. [PMID: 12819104 PMCID: PMC162038 DOI: 10.1128/iai.71.7.4127-4136.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Apoptotic host cell death is a critical determinant in the progression of microbial infections and outcome of resultant diseases. The potentially fatal human infection caused by Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever, involves the vascular endothelium of various organ systems of the host. Earlier studies have shown that survival of endothelial cells (EC) during this infection depends on their ability to activate the transcription factor nuclear factor kappa B (NF-kappa B). Here, we investigated the involvement of caspase cascades and associated signaling pathways in regulation of host cell apoptosis by NF-kappa B. Infection of cultured human EC with R. rickettsii with simultaneous inhibition of NF-kappa B induced the activation of apical caspases 8 and 9 and also the executioner enzyme, caspase 3, whereas infection alone had no significant effect. Inhibition of either caspase-8 or caspase-9 with specific cell-permeating peptide inhibitors caused a significant decline in the extent of apoptosis, confirming their importance. The peak caspase-3 activity occurred at 12 h postinfection and led to cleavage of poly(ADP-ribose) polymerase, followed by DNA fragmentation and apoptosis. However, the activities of caspases 6 and 7, other important downstream executioners, remained unchanged. Caspase-9 activation was mediated through the mitochondrial pathway of apoptosis, as evidenced by loss of transmembrane potential and cytoplasmic release of cytochrome c. These findings suggest that activation of NF-kappa B is required for maintenance of mitochondrial integrity of host cells and protection against infection-induced apoptotic death by preventing activation of caspase-9- and caspase-8-mediated pathways. Targeted inhibition of NF-kappa B may therefore be exploited to enhance the clearance of infections with R. rickettsii and other intracellular pathogens with similar survival strategies.
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Affiliation(s)
- Suresh G Joshi
- Hematology-Oncology Unit, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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