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Castro MBD, Szabó MPJ, Aquino LPCTD, Dagnoni AS, Alessi AC, Costa MT, Nakaghi ACH, Santi MD, Calchi AC, André MR, Machado RZ. Immunophenotypical and pathological changes in dogs experimentally infected with Ehrlichia canis. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA = BRAZILIAN JOURNAL OF VETERINARY PARASITOLOGY : ORGAO OFICIAL DO COLEGIO BRASILEIRO DE PARASITOLOGIA VETERINARIA 2022; 31:e021621. [PMID: 35416862 PMCID: PMC9901872 DOI: 10.1590/s1984-29612022020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/11/2022] [Indexed: 11/22/2022]
Abstract
Canine monocytic ehrlichiosis (CME) is one of the most important tick-borne diseases worldwide, with multisystemic presentations. Immune dysregulation has been proposed as the primary mechanism involved in its pathogenesis and in tissue injury in dogs with CME. Experimental infection of German Shepherd dogs in the present study demonstrated that CME caused marked pathological changes in their lymph nodes and spleen, and also gave rise to mononuclear infiltration in organs and tissues. Immunophenotyping of cells in lymph nodes, spleen and injured tissues highlighted differences in lymphocyte subsets, local expression of immunoglobulin subclasses and MHCII molecules between infected and control dogs. These findings suggest that the immunophenotypic and immunopathological changes in dogs with acute experimental CME are related to Th1 bias and compartmentalized immune response.
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Affiliation(s)
| | - Matias Pablo Juan Szabó
- Faculdade de Medicina Veterinária, Universidade Federal de Uberlândia - UFU, Uberlândia, MG, Brasil
| | | | | | - Antonio Carlos Alessi
- Departamento de Patologia, Reprodução e Saúde Única, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
| | - Mirela Tinucci Costa
- Departamento de Clínica e Cirurgia Veterinária, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
| | | | - Mariele De Santi
- Departamento de Patologia, Reprodução e Saúde Única, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
| | - Ana Claúdia Calchi
- Departamento de Patologia, Reprodução e Saúde Única, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
| | - Marcos Rogério André
- Departamento de Patologia, Reprodução e Saúde Única, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
| | - Rosangela Zacarias Machado
- Departamento de Patologia, Reprodução e Saúde Única, Faculdade Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil
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Torina A, Blanda V, Villari S, Piazza A, La Russa F, Grippi F, La Manna MP, Di Liberto D, de la Fuente J, Sireci G. Immune Response to Tick-Borne Hemoparasites: Host Adaptive Immune Response Mechanisms as Potential Targets for Therapies and Vaccines. Int J Mol Sci 2020; 21:ijms21228813. [PMID: 33233869 PMCID: PMC7699928 DOI: 10.3390/ijms21228813] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/12/2020] [Accepted: 11/12/2020] [Indexed: 02/06/2023] Open
Abstract
Tick-transmitted pathogens cause infectious diseases in both humans and animals. Different types of adaptive immune mechanisms could be induced in hosts by these microorganisms, triggered either directly by pathogen antigens or indirectly through soluble factors, such as cytokines and/or chemokines, secreted by host cells as response. Adaptive immunity effectors, such as antibody secretion and cytotoxic and/or T helper cell responses, are mainly involved in the late and long-lasting protective immune response. Proteins and/or epitopes derived from pathogens and tick vectors have been isolated and characterized for the immune response induced in different hosts. This review was focused on the interactions between tick-borne pathogenic hemoparasites and different host effector mechanisms of T- and/or B cell-mediated adaptive immunity, describing the efforts to define immunodominant proteins or epitopes for vaccine development and/or immunotherapeutic purposes. A better understanding of these mechanisms of host immunity could lead to the assessment of possible new immunotherapies for these pathogens as well as to the prediction of possible new candidate vaccine antigens.
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Affiliation(s)
- Alessandra Torina
- Area Diagnostica Sierologica, Istituto Zooprofilattico Sperimentale della Sicilia, via Gino Marinuzzi 3, 90129 Palermo, Italy; (A.T.); (F.G.)
- Laboratorio di Riferimento OIE Theileriosi, Istituto Zooprofilattico Sperimentale della Sicilia, via Gino Marinuzzi 3, 90129 Palermo, Italy
| | - Valeria Blanda
- Laboratorio di Riferimento OIE Theileriosi, Istituto Zooprofilattico Sperimentale della Sicilia, via Gino Marinuzzi 3, 90129 Palermo, Italy
- Laboratorio di Entomologia e Controllo Vettori Ambientali, Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90129 Palermo, Italy; (S.V.); (A.P.); (F.L.R.)
- Correspondence:
| | - Sara Villari
- Laboratorio di Entomologia e Controllo Vettori Ambientali, Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90129 Palermo, Italy; (S.V.); (A.P.); (F.L.R.)
| | - Antonio Piazza
- Laboratorio di Entomologia e Controllo Vettori Ambientali, Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90129 Palermo, Italy; (S.V.); (A.P.); (F.L.R.)
| | - Francesco La Russa
- Laboratorio di Entomologia e Controllo Vettori Ambientali, Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90129 Palermo, Italy; (S.V.); (A.P.); (F.L.R.)
| | - Francesca Grippi
- Area Diagnostica Sierologica, Istituto Zooprofilattico Sperimentale della Sicilia, via Gino Marinuzzi 3, 90129 Palermo, Italy; (A.T.); (F.G.)
| | - Marco Pio La Manna
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (D.D.L.); (G.S.)
| | - Diana Di Liberto
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (D.D.L.); (G.S.)
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ronda de Toledo s/n, 13005 Ciudad Real, Spain;
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Guido Sireci
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (D.D.L.); (G.S.)
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Ehrlichia chaffeensis Outer Membrane Protein 1-Specific Human Antibody-Mediated Immunity Is Defined by Intracellular TRIM21-Dependent Innate Immune Activation and Extracellular Neutralization. Infect Immun 2019; 87:IAI.00383-19. [PMID: 31548319 PMCID: PMC6867850 DOI: 10.1128/iai.00383-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/18/2019] [Indexed: 01/05/2023] Open
Abstract
Antibodies are essential for immunity against Ehrlichia chaffeensis, and protective mechanisms involve blocking of ehrlichial attachment or complement and Fcγ-receptor-dependent destruction. In this study, we determined that major outer membrane protein 1 (OMP-19) hypervariable region 1 (HVR1)-specific human monoclonal antibodies (huMAbs) are protective through conventional extracellular neutralization and, more significantly, through a novel intracellular TRIM21-mediated mechanism. Antibodies are essential for immunity against Ehrlichia chaffeensis, and protective mechanisms involve blocking of ehrlichial attachment or complement and Fcγ-receptor-dependent destruction. In this study, we determined that major outer membrane protein 1 (OMP-19) hypervariable region 1 (HVR1)-specific human monoclonal antibodies (huMAbs) are protective through conventional extracellular neutralization and, more significantly, through a novel intracellular TRIM21-mediated mechanism. Addition of OMP-1-specific huMAb EHRL-15 (IgG1) prevented infection by blocking attachment/entry, a mechanism previously reported; conversely, OMP-1-specific huMAb EHRL-4 (IgG3) engaged intracellular TRIM21 and initiated an immediate innate immune response and rapid intracellular degradation of ehrlichiae. EHRL-4-TRIM21-mediated inhibition was significantly impaired in TRIM21 knockout THP-1 cells. EHRL-4 interacted with cytosolic Fc receptor TRIM21, observed by confocal microscopy and confirmed by co-immunoprecipitation. E. chaffeensis-EHRL-4-TRIM21 complexes caused significant upregulation of proinflammatory cytokine/chemokine transcripts and resulted in rapid (<30 min) nuclear accumulation of NF-κB and TRIM21 and ehrlichial destruction. We investigated the role of TRIM21 in the autophagic clearance of ehrlichiae in the presence of EHRL-4. Colocalization between EHRL-4-opsonized ehrlichiae, polyubiquitinated TRIM21, autophagy regulators (ULK1 and beclin 1) and effectors (LC3 and p62), and lysosome-associated membrane protein 2 (LAMP2) was observed. Moreover, autophagic flux defined by conversion of LC3I to LC3II and accumulation and degradation of p62 was detected, and EHRL-4-mediated degradation of E. chaffeensis was abrogated by the autophagy inhibitor 3-methyladenine. Our results demonstrate that huMAbs are capable of inhibiting E. chaffeensis infection by distinct effector mechanisms: extracellularly by neutralization and intracellularly by engaging TRIM21, which mediates a rapid innate immune response that mobilizes the core autophagy components, triggering localized selective autophagic degradation of ehrlichiae.
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McGill JL, Wang Y, Ganta CK, Boorgula GDY, Ganta RR. Antigen-Specific CD4 +CD8 + Double-Positive T Cells Are Increased in the Blood and Spleen During Ehrlichia chaffeensis Infection in the Canine Host. Front Immunol 2018; 9:1585. [PMID: 30050533 PMCID: PMC6050357 DOI: 10.3389/fimmu.2018.01585] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 06/26/2018] [Indexed: 12/11/2022] Open
Abstract
Ehrlichia chaffeensis is an obligate intracellular bacterium belonging to the order, Rickettsiales and is a frequent cause of severe and fatal tick-borne infection in people in North America. The reservoir host for E. chaffeensis is the white-tailed deer, while humans and dogs are regarded as common incidental hosts. In dogs, we and others have shown that E. chaffeensis establishes a chronic infection that persists for several weeks to months, while promoting the development of Th1 and Th17 cellular responses and pathogen-specific humoral immunity. We demonstrate here that vaccination with a live, attenuated clone of E. chaffeensis bearing a targeted mutation in the Ech_0230 gene neither promotes the development of long-lived cellular or humoral immunity, nor confers protection against secondary wild-type E. chaffeensis challenge. In dogs, a population of mature CD4+CD8+ double-positive (DP) T cells exists in the periphery that shares similarities with the DP T cell populations that have been described in humans and swine. Little is known about the function of these cells, particularly in the context of infectious diseases. Here, we demonstrate that canine DP T cells expand significantly in response to E. chaffeensis infection. Using in vitro antigen recall assays, we further demonstrate that canine DP T cells undergo clonal expansion, produce IFNγ and IL-17, and upregulate expression of granzyme B and granulysin. Together, our results demonstrate that DP T cells accumulate in the host during E. chaffeensis infection, and suggest that alternative lymphocyte populations may participate in the immune response to tick-borne infections in the incidental host.
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Affiliation(s)
- Jodi L. McGill
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Ying Wang
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Chanran K. Ganta
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Gunavanthi D. Y. Boorgula
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Roman R. Ganta
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
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5
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Ono E, Uede T. Implication of Soluble Forms of Cell Adhesion Molecules in Infectious Disease and Tumor: Insights from Transgenic Animal Models. Int J Mol Sci 2018; 19:ijms19010239. [PMID: 29342882 PMCID: PMC5796187 DOI: 10.3390/ijms19010239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 01/10/2018] [Accepted: 01/12/2018] [Indexed: 12/26/2022] Open
Abstract
Cell adhesion molecules (CAMs) are surface ligands, usually glycoproteins, which mediate cell-to-cell adhesion. They play a critical role in maintaining tissue integrity and mediating migration of cells, and some of them also act as viral receptors. It has been known that soluble forms of the viral receptors bind to the surface glycoproteins of the viruses and neutralize them, resulting in inhibition of the viral entry into cells. Nectin-1 is one of important CAMs belonging to immunoglobulin superfamily and herpesvirus entry mediator (HVEM) is a member of the tumor necrosis factor (TNF) receptor family. Both CAMs also act as alphaherpesvirus receptor. Transgenic mice expressing the soluble form of nectin-1 or HVEM showed almost complete resistance against the alphaherpesviruses. As another CAM, sialic acid-binding immunoglobulin-like lectins (Siglecs) that recognize sialic acids are also known as an immunoglobulin superfamily member. Siglecs play an important role in the regulation of immune cell functions in infectious diseases, inflammation, neurodegeneration, autoimmune diseases and cancer. Siglec-9 is one of Siglecs and capsular polysaccharide (CPS) of group B Streptococcus (GBS) binds to Siglec-9 on neutrophils, leading to suppress host immune response and provide a survival advantage to the pathogen. In addition, Siglec-9 also binds to tumor-produced mucins such as MUC1 to lead negative immunomodulation. Transgenic mice expressing the soluble form of Siglec-9 showed significant resistance against GBS infection and remarkable suppression of MUC1 expressing tumor proliferation. This review describes recent developments in the understanding of the potency of soluble forms of CAMs in the transgenic mice and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.
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Affiliation(s)
- Etsuro Ono
- Department of Biomedicine, Center of Biomedical Research, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Toshimitsu Uede
- Division of Molecular Immunology, Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
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6
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A soluble form of Siglec-9 provides a resistance against Group B Streptococcus (GBS) infection in transgenic mice. Microb Pathog 2016; 99:106-110. [DOI: 10.1016/j.micpath.2016.08.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 08/01/2016] [Accepted: 08/09/2016] [Indexed: 11/18/2022]
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7
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Nair ADS, Cheng C, Ganta CK, Sanderson MW, Alleman AR, Munderloh UG, Ganta RR. Comparative Experimental Infection Study in Dogs with Ehrlichia canis, E. chaffeensis, Anaplasma platys and A. phagocytophilum. PLoS One 2016; 11:e0148239. [PMID: 26840398 PMCID: PMC4739612 DOI: 10.1371/journal.pone.0148239] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/14/2016] [Indexed: 11/30/2022] Open
Abstract
Dogs acquire infections with the Anaplasmataceae family pathogens, E. canis, E. chaffeensis, E. ewingii, A. platys and A. phagocytophilum mostly during summer months when ticks are actively feeding on animals. These pathogens are also identified as causing diseases in people. Despite the long history of tick-borne diseases in dogs, much remains to be defined pertaining to the clinical and pathological outcomes of infections with these pathogens. In the current study, we performed experimental infections in dogs with E. canis, E. chaffeensis, A. platys and A. phagocytophilum. Animals were monitored for 42 days to evaluate infection-specific clinical, hematological and pathological differences. All four pathogens caused systemic persistent infections detectible throughout the 6 weeks of infection assessment. Fever was frequently detected in animals infected with E. canis, E. chaffeensis, and A. platys, but not in dogs infected with A. phagocytophilum. Hematological differences were evident in all four infected groups, although significant overlap existed between the groups. A marked reduction in packed cell volume that correlated with reduced erythrocytes and hemoglobin was observed only in E. canis infected animals. A decline in platelet numbers was common with E. canis, A. platys and A. phagocytophilum infections. Histopathological lesions in lung, liver and spleen were observed in all four groups of infected dogs; infection with E. canis had the highest pathological scores, followed by E. chaffeensis, then A. platys and A. phagocytophilum. All four pathogens induced IgG responses starting on day 7 post infection, which was predominantly comprised of IgG2 subclass antibodies. This is the first detailed investigation comparing the infection progression and host responses in dogs after inoculation with four pathogens belonging to the Anaplasmataceae family. The study revealed a significant overlap in clinical, hematological and pathological changes resulting from the infections.
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Affiliation(s)
- Arathy D. S. Nair
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Chuanmin Cheng
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Chanran K. Ganta
- Kansas State Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Michael W Sanderson
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Arthur R. Alleman
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Ulrike G. Munderloh
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Roman R. Ganta
- Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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Cunningham AF, Flores-Langarica A, Bobat S, Dominguez Medina CC, Cook CNL, Ross EA, Lopez-Macias C, Henderson IR. B1b cells recognize protective antigens after natural infection and vaccination. Front Immunol 2014; 5:535. [PMID: 25400633 PMCID: PMC4215630 DOI: 10.3389/fimmu.2014.00535] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/10/2014] [Indexed: 12/18/2022] Open
Abstract
There are multiple, distinct B-cell populations in human beings and other animals such as mice. In the latter species, there is a well-characterized subset of B-cells known as B1 cells, which are enriched in peripheral sites such as the peritoneal cavity but are rare in the blood. B1 cells can be further subdivided into B1a and B1b subsets. There may be additional B1 subsets, though it is unclear if these are distinct populations or stages in the developmental process to become mature B1a and B1b cells. A limitation in understanding B1 subsets is the relative paucity of specific surface markers. In contrast to mice, the existence of B1 cells in human beings is controversial and more studies are needed to investigate the nature of these enigmatic cells. Examples of B1b antigens include pneumococcal polysaccharide and the Vi antigen from Salmonella Typhi, both used routinely as vaccines in human beings and experimental antigens such as haptenated-Ficoll. In addition to inducing classical T-dependent responses some proteins are B1b antigens and can induce T-independent (TI) immunity, examples include factor H binding protein from Borrelia hermsii and porins from Salmonella. Therefore, B1b antigens can be proteinaceous or non-proteinaceous, induce TI responses, memory, and immunity, they exist in a diverse range of pathogenic bacteria, and a single species can contain multiple B1b antigens. An unexpected benefit to studying B1b cells is that they appear to have a propensity to recognize protective antigens in bacteria. This suggests that studying B1b cells may be rewarding for vaccine design as immunoprophylactic and immunotherapeutic interventions become more important due to the decreasing efficacy of small molecule antimicrobials.
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Affiliation(s)
- Adam F Cunningham
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Adriana Flores-Langarica
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Saeeda Bobat
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Carmen C Dominguez Medina
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Charlotte N L Cook
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Ewan A Ross
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
| | - Constantino Lopez-Macias
- Medical Research Unit on Immunochemistry, National Medical Centre "Siglo XXI", Specialties Hospital, Mexican Institute for Social Security (IMSS) , Mexico City , Mexico
| | - Ian R Henderson
- MRC Centre for Immune Regulation, Institute for Microbiology and Infection, School of Immunity and Infection, Institute for Biomedical Research, Medical School, University of Birmingham , Birmingham , UK
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Major species-specific antibody epitopes of the Ehrlichia chaffeensis p120 and E. canis p140 orthologs in surface-exposed tandem repeat regions. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:982-90. [PMID: 19420187 DOI: 10.1128/cvi.00048-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ehrlichia chaffeensis and E. canis have a small subset of tandem repeat (TR)-containing protein orthologs, including p120/p140, which elicit strong antibody responses. The TR regions of these protein orthologs are immunoreactive, but the molecular characteristics of the p120/p140 epitopes have not been determined. In this study, the immunodeterminants of the E. chaffeensis p120 and E. canis p140 were identified and molecularly defined. Major antibody epitope-containing regions of both p120 and p140 were localized to the TR regions, which reacted strongly by Western immunoblotting with antibodies in sera from E. chaffeensis-infected dogs or patients and E. canis-infected dogs, respectively. Single continuous species-specific major epitopes within the E. chaffeensis p120 and E. canis p140 TRs were mapped to homologous surface-exposed glutamate/aspartate-rich regions (19 to 22 amino acids). In addition, minor cross-reactive epitopes were localized to homologous N- and C-terminal regions of p120 and p140. Furthermore, although the native and recombinant p120 and p140 proteins exhibited higher-than-predicted molecular masses, posttranslational modifications were not present on abnormally migrating p120 and p140 TR recombinant proteins as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry.
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10
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Birkner K, Steiner B, Rinkler C, Kern Y, Aichele P, Bogdan C, von Loewenich FD. The elimination of Anaplasma phagocytophilum requires CD4+ T cells, but is independent of Th1 cytokines and a wide spectrum of effector mechanisms. Eur J Immunol 2009; 38:3395-410. [PMID: 19039769 DOI: 10.1002/eji.200838615] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Anaplasma phagocytophilum is a Gram-negative, obligate intracellular bacterium that exhibits a striking tropism for neutrophils. When we depleted mice of neutrophils, we found that murine susceptibility to anaplasmal infection was dependent on their presence. While serving as sites of bacterial replication, neutrophils do not seem to act as efficient killer cells in A. phagocytophilum infection, because mice deficient for antimicrobial effectors of neutrophils such as myeloperoxidase, granulocyte elastase, and cathepsin G were fully competent in pathogen elimination. To identify components of the immune system other than neutrophils that control A. phagocytophilum, we studied the course of infection in several gene-deficient mouse strains. IFN-gamma production by NK cells was important for initial defense, but not critical for pathogen elimination. In contrast, bacterial clearance was strictly dependent on CD4(+) T cells, but unexpectedly achieved in the absence of perforin, Fas/FasL and major Th1 cytokines such as IL-12, IFN-gamma, and MCP-1. These findings provide a novel paradigm for the control of an intracellular pathogen, which appears to be strikingly different from the CD4(+) T cell-, IL-12-, and IFN-gamma-dependent immunity to other intracellular bacteria.
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Affiliation(s)
- Katharina Birkner
- Department of Medical Microbiology and Hygiene, Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany
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11
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Chapes SK, Ganta RR. Defining the immune response to Ehrlichia species using murine models. Vet Parasitol 2008; 158:344-59. [PMID: 19028013 DOI: 10.1016/j.vetpar.2008.09.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 09/06/2008] [Accepted: 09/09/2008] [Indexed: 01/01/2023]
Abstract
Pathogenic bacteria belonging to the family Anaplasmataceae include species of the genera Ehrlichia and Anaplasma. Ehrlichia chaffeensis, first known as the causative agent of human monocytic ehrlichiosis, also infects several vertebrate hosts including white-tailed deer, dogs, coyotes and goats. E. chaffeensis is transmitted from the bite of an infected hard tick, such as Amblyomma americanum. E. chaffeensis and other tick-transmitted pathogens have adapted to both the tick and vertebrate host cell environments. Although E. chaffeensis persists in both vertebrate and tick hosts for long periods of time, little is known about that process. Immunological studies will be valuable in assessing how the pathogen persists in nature in both vertebrate and invertebrate hosts. Understanding the host immune response to the pathogen originating from dual host backgrounds is also important to develop effective methods of diagnosis, control and treatment. In this paper, we provide our perspective of the current understanding of the immune response against E. chaffeensis in relation to other related Anaplasmataceae pathogens.
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Affiliation(s)
- Stephen K Chapes
- Division of Biology, College of Arts and Sciences, Kansas State University, Manhattan, KS 66506, USA
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A variable-length PCR target protein of Ehrlichia chaffeensis contains major species-specific antibody epitopes in acidic serine-rich tandem repeats. Infect Immun 2008; 76:1572-80. [PMID: 18212082 DOI: 10.1128/iai.01466-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ehrlichia chaffeensis and E. canis have a small subset of tandem repeat (TR)-containing proteins that elicit strong host immune responses and are associated with host-pathogen interactions. In a previous study, we molecularly characterized a highly conserved 19-kDa major immunoreactive protein (gp19) of E. canis and identified the corresponding TR-containing ortholog variable-length PCR target (VLPT) protein in E. chaffeensis. In this study, the native 32-kDa VLPT protein was identified and the immunodeterminants defined in order to further understand the molecular basis of the host immune response to E. chaffeensis. Synthetic and/or recombinant polypeptides corresponding to various regions of VLPT were used to localize major antibody epitopes to the TR-containing region. Major antibody epitopes were identified in three nonidentical repeats (R2, R3, and R4), which reacted strongly with antibodies in sera from an E. chaffeensis-infected dog and human monocytotropic ehrlichiosis patients. VLPT-R3 and VLPT-R2 reacted most strongly with antibody, and the epitope was further localized to a nearly identical proximal 17-amino-acid region common between these repeats that was species specific. The epitope in R4 was distinct from that of R2 and R3 and was found to have conformational dependence. VLPT was detected in supernatants from infected cells, indicating that the protein was secreted. VLPT was localized on both reticulate and dense-core cells, and it was found extracellularly in the morula fibrillar matrix and associated with the morula membrane.
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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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Nethery KA, Doyle CK, Zhang X, McBride JW. Ehrlichia canis gp200 contains dominant species-specific antibody epitopes in terminal acidic domains. Infect Immun 2007; 75:4900-8. [PMID: 17682040 PMCID: PMC2044547 DOI: 10.1128/iai.00041-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Species-specific antibody epitopes within several major immunoreactive protein orthologs of Ehrlichia species have recently been identified and molecularly characterized. In this study, dominant B-cell epitopes within the acidic (pI 5.35) ankyrin repeat-containing 200-kDa major immunoreactive protein (gp200) of Ehrlichia canis were defined. The E. canis gp200 gene (4,263 bp; 1,421 amino acids) was cloned and expressed as four (N-terminal, 1,107 bp; N-internal, 910 bp; C-internal, 1,000 bp; and C-terminal, 1,280 bp) overlapping recombinant proteins. The N-terminal, C-internal, and C-terminal polypeptides (369, 332, and 426 amino acids, respectively) were strongly recognized by antibody, and the major epitope(s) in these polypeptides was mapped to four polypeptide regions (40 to 70 amino acids). Smaller overlapping recombinant polypeptides (14 to 15 amino acids) spanning these regions identified five strongly immunoreactive species-specific epitopes that exhibited conformational dependence. The majority of the epitopes (four) were located in two strongly acidic (pI 4 to 4.9) domains in the distal N- and C-terminal regions of the protein flanking the centralized ankyrin domain-containing region. The amino acid content of the epitope-containing domains included a high proportion of strongly acidic amino acids (glutamate and aspartate), and these domains appear to have important biophysical properties that influence the antibody response to gp200.
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Affiliation(s)
- Kimberly A Nethery
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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Bitsaktsis C, Nandi B, Racine R, MacNamara KC, Winslow G. T-Cell-independent humoral immunity is sufficient for protection against fatal intracellular ehrlichia infection. Infect Immun 2007; 75:4933-41. [PMID: 17664264 PMCID: PMC2044530 DOI: 10.1128/iai.00705-07] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Although humoral immunity has been shown to contribute to host defense during intracellular bacterial infections, its role has generally been ancillary. Instead, CD4 T cells are often considered to play the dominant role in protective immunity via their production of type I cytokines. Our studies of highly pathogenic Ehrlichia bacteria isolated from Ixodes ovatus (IOE) reveal, however, that this paradigm is not always correct. Immunity to IOE infection can be induced by infection with a closely related weakly pathogenic ehrlichia, Ehrlichia muris. Type I cytokines (i.e., gamma interferon, tumor necrosis factor alpha, and interleukin-12) were not necessary for E. muris-induced immunity. In contrast, humoral immunity was essential, as shown by the fact that E. muris-infected B-cell-deficient mice were not protected from IOE challenge and because E. muris immunization was effective in CD4-, CD8-, and major histocompatibility complex (MHC) class II-deficient mice. Immunity was unlikely due to nonspecific inflammation, as prior infection with Listeria monocytogenes did not induce immunity to IOE. Antisera from both wild-type and MHC-II-deficient mice provided at least partial resistance to challenge infection, and protection could also be achieved following transfer of total, but not B-cell-depleted, splenocytes obtained from E. muris-immunized mice. The titers of class-switched antibodies in immunized CD4 T-cell- and MHC class II-deficient mice, although lower than those observed in immunized wild-type mice, were significant, indicating that E. muris can induce class switch recombination in the absence of classical T-cell-mediated help. These studies highlight a major protective role for classical T-cell-independent humoral immunity during an intracellular bacterial infection.
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Affiliation(s)
- Constantine Bitsaktsis
- Wadsworth Center, New York State Department of Health, PO Box 22002, Albany, New York 12201-2002, USA
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Pammit MA, Raulie EK, Lauriano CM, Klose KE, Arulanandam BP. Intranasal vaccination with a defined attenuated Francisella novicida strain induces gamma interferon-dependent antibody-mediated protection against tularemia. Infect Immun 2006; 74:2063-71. [PMID: 16552035 PMCID: PMC1418901 DOI: 10.1128/iai.74.4.2063-2071.2006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Francisella tularensis is an intracellular gram-negative bacterium that is the causative agent of tularemia and a potential bioweapon. We have characterized the efficacy of a defined F. novicida mutant (DeltaiglC) as a live attenuated vaccine against subsequent intranasal challenge with the wild-type organism. Animals primed with the F. novicida DeltaiglC (KKF24) mutant induced robust splenic gamma interferon (IFN-gamma) and interleukin-12 (IL-12) recall responses with negligible IL-4 production as well as the production of antigen-specific serum immunoglobulin G1 (IgG1) and IgG2a antibodies. BALB/c mice vaccinated intranasally (i.n.) with KKF24 and subsequently challenged with wild-type F. novicida (100 and 1,000 50% lethal doses) were highly protected (83% and 50% survival, respectively) from the lethal challenges. The protection conferred by KKF24 vaccination was shown to be highly dependent on endogenous IFN-gamma production and also was mediated by antibodies that could be adoptively transferred to naive B-cell-deficient mice by inoculation of immune sera. Collectively, the results demonstrate that i.n. vaccination with KKF24 induces a vigorous Th1-type cytokine and antibody response that is protective against subsequent i.n. challenge with the wild-type strain. This is the first report of a defined live attenuated strain providing protection against the inhalation of F. novicida.
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MESH Headings
- Administration, Intranasal
- Adoptive Transfer
- Animals
- Antibodies, Bacterial/administration & dosage
- Antibodies, Bacterial/biosynthesis
- Antibodies, Bacterial/physiology
- Bacterial Vaccines/administration & dosage
- Bacterial Vaccines/immunology
- Cells, Cultured
- Female
- Fluorescent Antibody Technique
- Francisella/genetics
- Francisella/immunology
- Interferon-gamma/physiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mutation
- Pneumonia, Bacterial/immunology
- Pneumonia, Bacterial/microbiology
- Pneumonia, Bacterial/pathology
- Th1 Cells/immunology
- Tularemia/immunology
- Tularemia/prevention & control
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/genetics
- Vaccines, Attenuated/immunology
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Affiliation(s)
- Michael A Pammit
- Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA
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Abstract
PURPOSE OF REVIEW Discusses recent developments in the study of immunity and host defense against the monocytic ehrlichiae in 2003 and 2004. The review does not address anaplasmoses, as the anaplasmae were recently re-classified into the genus Anaplasma, and are distinct in cell tropism from the ehrlichiae. RECENT FINDINGS The features of the immune responses against these emerging Gram-negative obligate intracellular pathogens are only beginning to be understood. Important advances in our ability to study host defense include the development of new experimental mouse models. Recent studies have defined possible mechanisms of innate immune subversion in human monocytes, as well as roles for lymphocyte subsets and type I cytokines during mouse infection. Other studies in the mouse suggest that cytokine production by CD8 T cells may contribute to immunopathology. New data also support a role for humoral immunity during host defense against these intracellular pathogens. SUMMARY The use of new animal models will facilitate research of the mechanisms of innate, adaptive, and pathological immune responses, and will enhance our understanding of human immunity to the ehrlichiae as well as to other pathogenic intracellular bacteria.
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Affiliation(s)
- Gary M Winslow
- Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA.
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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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