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Hove P, Madesh S, Nair A, Jaworski D, Liu H, Ferm J, Kleinhenz MD, Highland MA, Curtis AK, Coetzee JF, Noh SM, Wang Y, Genda D, Ganta RR. Targeted mutagenesis in Anaplasma marginale to define virulence and vaccine development against bovine anaplasmosis. PLoS Pathog 2022; 18:e1010540. [PMID: 35576225 PMCID: PMC9135337 DOI: 10.1371/journal.ppat.1010540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/26/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
Tick-borne Anaplasma species are obligate, intracellular, bacterial pathogens that cause important diseases globally in people, agricultural animals, and dogs. Targeted mutagenesis methods are yet to be developed to define genes essential for these pathogens. In addition, vaccines conferring protection against diseases caused by Anaplasma species are not available. Here, we describe a targeted mutagenesis method for deletion of the phage head-to-tail connector protein (phtcp) gene in Anaplasma marginale. The mutant did not cause disease and exhibited attenuated growth in its natural host (cattle). We then assessed its ability to confer protection against wild-type A. marginale infection challenge. Additionally, we compared vaccine protection with the mutant to that of whole cell A. marginale inactivated antigens as a vaccine (WCAV) candidate. Upon infection challenge, non-vaccinated control cattle developed severe disease, with an average 57% drop in packed cell volume (PCV) between days 26-31 post infection, an 11% peak in erythrocytic infection, and apparent anisocytosis. Conversely, following challenge, all animals receiving the live mutant did not develop clinical signs or anemia, or erythrocyte infection. In contrast, the WCAV vaccinees developed similar disease as the non-vaccinees following A. marginale infection, though the peak erythrocyte infection reduced to 6% and the PCV dropped 43%. This is the first study describing targeted mutagenesis and its application in determining in vivo virulence and vaccine development for an Anaplasma species pathogen. This study will pave the way for similar research in related Anaplasma pathogens impacting multiple hosts.
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Affiliation(s)
- Paidashe Hove
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
- Department of Pathobiology, School of Veterinary Medicine, St. George's University, West Indies, Grenada
| | - Swetha Madesh
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Arathy Nair
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Deborah Jaworski
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Huitao Liu
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Jonathan Ferm
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Michael D Kleinhenz
- Department of Clinical Sciences, Kansas State University, Manhattan, Kansas, United States of America
| | - Margaret A Highland
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Andrew K Curtis
- Department of Anatomy and Physiology and, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Johann F Coetzee
- Department of Anatomy and Physiology and, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Susan M Noh
- Animal Diseases Research Unit, USDA-ARS, 3003 ADBF, Pullman, Washington, United States of America
| | - Ying Wang
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Dominica Genda
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
| | - Roman R Ganta
- Center of Excellence for Vector-Borne Diseases (CEVBD), Department of Diagnostic Medicine/Pathobiology, Manhattan, Kansas, United States of America
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Curtis AK, Reif KE, Kleinhenz MD, Martin MS, Skinner B, Kelly SM, Jones DE, Schaut RG, Reppert EJ, Montgomery SR, Narasimhan B, Anantatat T, Jaberi-Douraki M, Coetzee JF. Development of a subcutaneous ear implant to deliver an anaplasmosis vaccine to dairy steers. J Anim Sci 2020; 98:5691273. [PMID: 31889177 DOI: 10.1093/jas/skz392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/30/2019] [Indexed: 01/07/2023] Open
Abstract
Bovine anaplasmosis is the most prevalent tick-transmitted disease of cattle worldwide and a major obstacle to profitable beef production. Use of chlortetracycline-medicated feed to control active anaplasmosis infections during the vector season has raised concerns about the potential emergence of antimicrobial resistance in bacteria that may pose a risk to human health. Furthermore, the absence of effectiveness data for a commercially available, conditionally licensed anaplasmosis vaccine is a major impediment to implementing anaplasmosis control programs. The primary objective of this study was to develop a single-dose vaccine delivery platform to produce long-lasting protective immunity against anaplasmosis infections. Twelve Holstein steers, aged 11 to 12 wk, were administered a novel 3-stage, single-dose vaccine against Anaplasma marginale, a major surface protein 1a. The vaccine consisted of a soluble vaccine administered subcutaneously (s.c.) for immune priming, a vaccine depot of a biodegradable polyanhydride rod with intermediate slow release of the vaccine for boosting immune response, and an immune-isolated vaccine platform for extended antigen release (VPEAR implant) deposited s.c. in the ear. Six calves were randomly assigned to 2 vaccine constructs (n = 3) that featured rods and implants containing a combination of 2 different adjuvants, diethylaminoethyl (DEAE)-Dextran and Quil-A (Group A). The remaining 6 calves were randomly assigned to 2 vaccine constructs (n = 3) that featured rods and implants containing the same adjuvant (either DEAE-Dextran or Quil A) (Group B). Twenty-one months post-implantation, calves were challenged intravenously with A. marginale stabilate and were monitored weekly for signs of fever, decreased packed cell volume (PCV) and bacteremia. Data were analyzed using a mixed-effects model and chi-squared tests (SAS v9.04.01, SAS Institute, Cary, NC). Calves in Group A had higher PCV than calves in Group B (P = 0.006) at day 35 post-infection. Calves in Group A were less likely to require antibiotic intervention compared with calves in Group B (P = 0.014). Results indicate that calves exhibited diminished clinical signs of anaplasmosis when antigen was delivered with a combination of adjuvants as opposed to a single adjuvant. This demonstrates the feasibility of providing long-lasting protection against clinical bovine anaplasmosis infections using a subcutaneous ear implant vaccine construct.
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Affiliation(s)
- Andrew K Curtis
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS
| | - Kathryn E Reif
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS
| | | | - Miriam S Martin
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS
| | - Brandt Skinner
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS
| | - Sean M Kelly
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA
| | - Douglas E Jones
- Department of Veterinary Pathology, Iowa State University, Ames, IA.,Nanovaccine Institute, Iowa State University, Ames, IA
| | | | - Emily J Reppert
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS
| | | | - Balaji Narasimhan
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA.,Nanovaccine Institute, Iowa State University, Ames, IA
| | - Tippawan Anantatat
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS
| | | | - Johann F Coetzee
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS.,Nanovaccine Institute, Iowa State University, Ames, IA
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Liu Z, Peasley AM, Yang J, Li Y, Guan G, Luo J, Yin H, Brayton KA. The Anaplasma ovis genome reveals a high proportion of pseudogenes. BMC Genomics 2019; 20:69. [PMID: 30665414 PMCID: PMC6341658 DOI: 10.1186/s12864-018-5374-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/16/2018] [Indexed: 01/07/2023] Open
Abstract
Background The genus Anaplasma is made up of organisms characterized by small genomes that are undergoing reductive evolution. Anaplasma ovis, one of the seven recognized species in this genus, is an understudied pathogen of sheep and other ruminants. This tick-borne agent is thought to induce only mild clinical disease; however, small deficits may add to larger economic impacts due to the wide geographic distribution of this pathogen. Results In this report we present the first complete genome sequence for A. ovis and compare the genome features with other closely related species. The 1,214,674 bp A. ovis genome encodes 933 protein coding sequences, the split operon arrangement for ribosomal RNA genes, and more pseudogenes than previously recognized for other Anaplasma species. The metabolic potential is similar to other Anaplasma species. Anaplasma ovis has a small repertoire of surface proteins and transporters. Several novel genes are identified. Conclusions Analyses of these important features and significant gene families/genes with potential to be vaccine candidates are presented in a comparative context. The availability of this genome will significantly facilitate research for this pathogen.
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Affiliation(s)
- Zhijie Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China
| | - Austin M Peasley
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164-7040, USA
| | - Jifei Yang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China
| | - Youquan Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China
| | - Guiquan Guan
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China
| | - Jianxun Luo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China
| | - Hong Yin
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, People's Republic of China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases, Yangzhou, China
| | - Kelly A Brayton
- Program in Genomics, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164-7040, USA.
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Diaz-Sanchez S, Hernández-Jarguín A, Fernández de Mera IG, Alberdi P, Zweygarth E, Gortazar C, de la Fuente J. Draft Genome Sequences of Anaplasma phagocytophilum, A. marginale, and A. ovis Isolates from Different Hosts. Genome Announc 2018; 6:e01503-17. [PMID: 29437094 DOI: 10.1128/genomeA.01503-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here, we report the draft genome sequences of isolates of Anaplasma phagocytophilum, Anaplasma marginale, and Anaplasma ovis. The genomes of A. phagocytophilum (human), A. marginale (cattle), and A. ovis (goat) isolates from the United States were sequenced and characterized. This is the first report of an A. ovis genome sequence.
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Wei R, Liu HB, Jongejan F, Jiang BG, Chang QC, Fu X, Jiang JF, Jia N, Cao WC. Cultivation of Anaplasma ovis in the HL-60 human promyelocytic leukemia cell line. Emerg Microbes Infect 2017; 6:e83. [PMID: 28928415 PMCID: PMC5625320 DOI: 10.1038/emi.2017.70] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/15/2017] [Accepted: 07/18/2017] [Indexed: 01/07/2023]
Abstract
The tick-borne bacterium Anaplasma ovis is a widely distributed pathogen affecting sheep, goats and wild ruminants. Here, the HL-60 human promyelocytic leukemia cell line was used to isolate A. ovis from PCR-positive sheep and goats in Heilongjiang Province, China. Two weeks after inoculation, morulae were observed in cytoplasmic vacuoles in four different HL-60 cultures. Confocal microscopy using a Cy3-labeled A. ovis-specific probe confirmed that the HL-60 cells were infected with A. ovis. Cells from the 6th HL-60 subculture displayed positive fluorescence when incubated with A. ovis antiserum in the indirect fluorescent antibody assay. PCR amplification and sequencing of 16S rRNA, groEL, gltA, msp2 and msp4 Anaplasma genes revealed that the four A. ovis culture isolates were identical. Phylogenetic analysis showed that the sequences clustered with other A. ovis strains but could clearly be distinguished from other Anaplasma species. When the 18th subculture of infected HL-60 cells was examined by electron microscopy, lysosomes were often observed near the vacuoles. After the 24th subculture, Giemsa staining and PCR indicated that the HL-60 cells were negative for A. ovis. Although A. ovis can infect HL-60 cells for only four months, the ability of the organism to infect and multiply in HL-60 cells provides a tool to study intra-erythrocytic Anaplasma and host cell interactions.
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Affiliation(s)
- Ran Wei
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Hong-Bo Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Frans Jongejan
- Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, Utrecht 3584 CL, The Netherlands.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Bao-Gui Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Qiao-Cheng Chang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xue Fu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jia-Fu Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Na Jia
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Wu-Chun Cao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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6
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Silveira JAG, Silvestre BT, Bastos CV, Ribeiro MFB. Isolation and attempted cultivation of an Anaplasma marginale strain from Brazilian brown brocket deer (Mazama gouazoubira, Fisher, 1814) in the tick cell line IDE8. Ticks Tick Borne Dis 2016; 7:1102-1108. [PMID: 27612925 DOI: 10.1016/j.ttbdis.2016.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/31/2016] [Accepted: 09/02/2016] [Indexed: 11/26/2022]
Abstract
The aim of the study was to isolate and establish an Anaplasma marginale strain from Brazilian brown brocket deer, Mazama gouazoubira, in the Ixodes scapularis cell line IDE8. Blood from a free-living adult female M. gouazoubira naturally infected with A. marginale (MGI5) was inoculated intravenously into a splenectomized calf. When A. marginale rickettsemia was 2.5%, blood was collected and cryopreserved in liquid nitrogen with dimethylsulfoxide (DMSO). IDE8 cell cultures were infected with calf blood inoculated with the A. marginale (MG15) isolate. The cultures were monitored by examination of Giemsa-stained cytocentrifuge smears. Light microscopy of stained IDE8 samples revealed the first inclusions of A. marginale (MGI5) at 48days post-inoculation (d.p.i). The IDE8-infected cells contained parasitophorous vacuoles with amorphous material and a few cocci-like organisms. A sample from IDE8-infected cells from the 16th subculture (336 d.p.i.) was analyzed by nPCR, nucleotide sequencing, electron microscopy, and an indirect fluorescent antibody test (IFAT). The IFAT highlighted some IDE8-infected cells with intense fluorescence in the parasitophorous vacuole, while in other cells, fluorescence was observed only at the periphery. DNA from a culture of the MG15 isolate was amplified with A. marginale msp4 gene primers, and nucleotide sequencing of the PCR product and BLAST software analysis further confirmed 100% identity with the MGI5 blood isolate (GenBank no. JN022558.1). Electron microscopy revealed increased numbers of lysosomes in the cytoplasm of IDE8 cells. Several cells exhibited large vacuoles containing cellular debris and amorphous material. After the 29th subculture, it was not possible to detect compatible Anaplasma structures by light microscopy, and subculture samples tested negative in nPCR. Despite the failure of the attempt to establish A. marginale (MGI5) in IDE8 cells, the results demonstrated the isolate's ability to infect, survive and multiply, although in limited numbers, in IDE8 cells.
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Affiliation(s)
- Julia A G Silveira
- Department of Parasitology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
| | - Bruna T Silvestre
- Department of Parasitology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Camila V Bastos
- Department of Preventive Veterinary Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Múcio F B Ribeiro
- Department of Parasitology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Lis K, Fernández de Mera IG, Popara M, Cabezas-cruz A, Ayllón N, Zweygarth E, Passos LM, Broniszewska M, Villar M, Kocan KM, Ribeiro MF, Pfister K, de la Fuente J. Molecular and immunological characterization of three strains of Anaplasma marginale grown in cultured tick cells. Ticks Tick Borne Dis 2015; 6:522-9. [DOI: 10.1016/j.ttbdis.2015.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/16/2015] [Accepted: 04/17/2015] [Indexed: 11/18/2022]
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Baêta BA, Ribeiro CCDU, Teixeira RC, Cabezas-Cruz A, Passos LMF, Zweygarth E, Fonseca AH. Characterization of two strains of Anaplasma marginale isolated from cattle in Rio de Janeiro, Brazil, after propagation in tick cell culture. Ticks Tick Borne Dis 2014; 6:141-5. [PMID: 25468764 DOI: 10.1016/j.ttbdis.2014.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
IDE8 tick cell cultures have been used for the isolation and propagation of several isolates of Anaplasma marginale. The genetic heterogeneity of A. marginale strains in cattle is diverse in endemic regions worldwide and the analyses of msp1α (major surface protein 1 alpha) gene sequences have allowed the identification of different strains. This study reports the isolation and propagation of two new isolates of A. marginale in IDE8 cells from blood of two cattle and their morphological and molecular characterization using light microscopy and the msp1α gene, respectively. Small colonies were observed in cytospin smears of each of the isolates 60 days after culture initiation. Based on msp1α sequence variation, the two isolates were found to be separate strains and were named AmRio1 and AmRio2. Analysis of msp1α microsatellite in both strains resulted in a single genotype, genotype E. The amino acid sequence of one MSP1α tandem repeat from the strain AmRio1 resulted in a new sequence (named 162) with one amino acid change. The results of these phylogenetic analyses demonstrated that A. marginale strains from Brazil and Argentina formed two large clusters of which one was less divergent that the other.
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Affiliation(s)
- Bruna A Baêta
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.
| | - Carla C D U Ribeiro
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.
| | - Rafaella C Teixeira
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.
| | - Alejandro Cabezas-Cruz
- Center for Infection and Immunity of Lille (CIIL), INSERM U1019 - CNRS UMR 8204, Université Lille Nord de France, Institut Pasteur de Lille, Lille, France; SaBio, Instituto de Investigación de Recursos Cinegéticos, IREC-CSIC-UCLM-JCCM, Ciudad Real 13005, Spain.
| | - Lygia M F Passos
- Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
| | - Erich Zweygarth
- Institute for Comparative Tropical Medicine and Parasitology, Ludwig-Maximilians-Universität München, Munich, Germany; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X4, Onderstepoort 0110, South Africa
| | - Adivaldo H Fonseca
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.
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Lis K, Najm N, de la Fuente J, Fernández de Mera I, Zweygarth E, Pfister K, Passos LM. Use of Percoll gradients to purify Anaplasma marginale (Rickettsiales: Anaplasmataceae) from tick cell cultures. Ticks Tick Borne Dis 2014; 5:511-5. [PMID: 24877977 DOI: 10.1016/j.ttbdis.2014.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/16/2014] [Accepted: 03/24/2014] [Indexed: 11/20/2022]
Abstract
Anaplasma marginale (Rickettsiales: Anaplasmataceae) is an obligate intracellular bacterium that multiplies exclusively within membrane-bound vacuoles in the cytoplasm of host cells. A number of A. marginale isolates can be propagated in the Ixodes scapularis IDE8 tick cell line, which provides a reliable source of antigens for a wide variety of studies. However, because of its intracellular nature, separation of bacteria from host cell materials remains an important constraint for researchers. In the present study, we evaluated the use of Percoll gradients for purification of two Brazilian strains of A. marginale grown in IDE8 tick cells. The purified A. marginale monitored in Giemsa-stained smears contained only minimal amounts of IDE8 cell stroma. The total protein yields were 1.2mg and 1.7mg, while the DNA titers quantified with real-time PCR were 6.4×10(9) for UFMG1 and 4.87×10(9) for UFMG2 copies in the purified material, respectively. Additionally, we confirmed the viability of purified bacteria by infecting tick cells after being freshly purified and after retrieval from long-term storage. Importantly, the viability of the organisms is preserved after use of this separation method, and therefore the purified organisms can be used in enzymatic assays and other research approaches where live organisms would be preferred.
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Passos LMF. In vitro cultivation of Anaplasma marginale and A. phagocytophilum in tick cell lines: a review. ACTA ACUST UNITED AC 2013; 21:81-6. [PMID: 22832744 DOI: 10.1590/s1984-29612012000200002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/16/2012] [Indexed: 11/22/2022]
Abstract
Continuous cell lines have been established from several ixodid and argasid tick species, representing an excellent tool suitable for the isolation of pathogens and their subsequent propagation, which in turn allows the production of antigenic material for diagnostic tests, antibody and vaccine production, and also for studies on host-vector-pathogen relationships. This paper reviews the use of tick cells for culture initiation and maintenance of two obligate intracellular bacterial pathogens, Anaplasma marginale and Anaplasma phagocytophilum. These in vitro cultivation systems have been used in a wide range of studies, covering morphological ultrastructural analysis, genetics, proteomics and biological differences between strains, including genome transcriptional and protein expression approaches, enabling comparisons between host and vector cells. Thus, such systems open a new window for a better understanding of interactions between pathogens and tick cells. Last but not least, such systems contribute to the reduction in usage of animals for experimental research, as antigenic material can be produced in reasonably large quantities without the use of in vivo species-specific systems.
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Affiliation(s)
- Lygia Maria Friche Passos
- Departamento de Medicina Veterinária Preventiva, Instituto Nacional em Ciência e Tecnologia--Informação Genético-Sanitária da Pecuária Brasileira, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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12
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Bastos CV, Passos LMF, Vasconcelos MMC, Ribeiro MFB. In vitro establishment and propagation of a Brazilian strain of Anaplasma marginale with appendage in IDE8 (Ixodes scapularis) cells. Braz J Microbiol 2009; 40:399-403. [PMID: 24031379 PMCID: PMC3769711 DOI: 10.1590/s1517-838220090002000034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 04/22/2008] [Accepted: 03/13/2009] [Indexed: 12/04/2022] Open
Abstract
A Brazilian isolate of Anaplasma marginale with appendage was successfully established and maintained in vitro in a tick cell line (IDE8). Infection was confirmed by optical and transmission electron microscopy. In addition, primers MSP1aNF2 and MSP1aNR2 amplified products from DNA extracted from infected IDE8 cells. Comparisons with partial sequences of the msp1α gene and the complete genome of A. marginale confirmed that the sequences of amplified fragments were from the A. marginale genome. This is the first establishment of a Brazilian A. marginale isolate in tick cells, representing a new system for biological and molecular studies and also a new source of material for diagnosis and development of vaccines.
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Affiliation(s)
- Camila V Bastos
- Departamento de Parasitologia, Universidade Federal de Minas Gerais , Belo Horizonte, MG , Brasil
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Coetzee JF, Schmidt PL, Apley MD, Reinbold JB, Kocan KM. Comparison of the complement fixation test and competitive ELISA for serodiagnosis ofAnaplasma marginaleinfection in experimentally infected steers. Am J Vet Res 2007; 68:872-8. [PMID: 17669027 DOI: 10.2460/ajvr.68.8.872] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare sensitivity of a complement fixation (CF) test and competitive ELISA (cELISA) for detection of Anaplasma marginale in experimentally infected steers. ANIMALS 40 crossbred (Angus-Simmental) steers. PROCEDURES Steers were inoculated with 2.6 x 10(9) A marginale-infected erythrocytes (day 0). Blood samples were collected on days 9, 13, 20, 28, 34, 41, 61, 96, 126, and 156 days after inoculation. The percentage of parasitized erythrocytes (PPE) was determined by microscopic examination of stained blood films, and sera were evaluated with the CF test and cELISA by use of USDA-approved methods. Sensitivity and agreement (kappa statistic) between the 2 methods were determined. Persistent infections were confirmed by inoculation of blood obtained from infected steers into susceptible, splenectomized calves. RESULTS 9 days after inoculation, sensitivity of the cELISA was 47.5%, whereas the CF test failed to identify seropositive steers. After day 13, sensitivity of the cELISA and CF test was 100% and 20%, respectively. During peak parasitemia (day 20), sensitivity of the cELISA and CF test was 100%. Thereafter, sensitivity of the CF test fluctuated between 7.5% and 37.5%, whereas sensitivity of the cELISA remained at 100%. Overall sensitivity of the cELISA and CF test was 94.8% and 26.5%, respectively (kappa statistic, 0.039). CONCLUSIONS AND CLINICAL RELEVANCE The cELISA had superior sensitivity for serologic detection of A marginale. The CF test and cELISA each had a high percentage of false-negative results during the prepatent period. These findings are relevant for export certification and anaplasmosis prevention or eradication programs.
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Affiliation(s)
- Johann F Coetzee
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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14
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Blouin EF, de la Fuente J, Garcia-Garcia JC, Sauer JR, Saliki JT, Kocan KM. Applications of a cell culture system for studying the interaction ofAnaplasmamarginale with tick cells. Anim Health Res Rev 2007. [DOI: 10.1079/ahrr200241] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractA cell culture system for the tick-borne rickettsiaAnaplasma marginaleoffers new opportunities for research on this economically important pathogen of cattle.A. marginalemultiplies in membrane-bound inclusions in host cells. Whereas erythrocytes appear to be the only site of infection in cattle,A. marginaleundergoes a complex developmental cycle in ticks and transmission occurs via the salivary glands during feeding. We recently developed a cell culture system forA. marginaleusing a cell line derived from embryos ofIxodes scapularis. Here we review the use of this cell culture system for studying the interaction ofA. marginalewith tick cells. Several assays were developed using theA. marginale/tick cell system. An adhesion assay was developed for the identification of proteins required byA. marginalefor adhesion to tick cells. The effect of antibodies against selected major surface proteins in inhibitingA. marginaleinfection was tested in an assay that allowed further confirmation of the role of surface proteins in the infection of tick cells. A drug screening assay forA. marginalewas developed and provides a method of initial drug selection without the use of cattle. The culture system was used to test for enhancing effects of tick saliva and saliva components onA. marginaleinfection. The tick cell culture system has proved to be a good model for studyingA. marginale–tick interactions. Information gained from these studies may be applicable to other closely related tick-borne pathogens that have been propagated in the same tick cell line.
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de la Fuente J, Garcia-Garcia JC, Blouin EF, Rodríguez SD, García MA, Kocan KM. Evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogenAnaplasma marginale. Anim Health Res Rev 2007. [DOI: 10.1079/ahrr200132] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe major surface protein (MSP) 1a of the ehrlichial cattle pathogenAnaplasma marginale, encoded by the single-copy genemsp1α, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells.msp1αhas been found to be a stable genetic marker for the identification of geographic isolates ofA. marginalethroughout development in acutely and persistently infected cattle and in ticks. The molecular weight of MSP1a varies among geographic isolates ofA. marginalebecause of a varying number of tandemly repeated peptides of 28–29 amino acids. Variation in the sequence of the tandem repeats occurs within and among isolates, and may have resulted from evolutionary pressures exerted by ligand–receptor and host–parasite interactions. These repeated sequences include markers for tick transmissibility that may be important in the identification of ehrlichial pathogens because they may influence control strategies and the design of subunit vaccines.
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Kocan KM, Yoshioka J, Sonenshine DE, de la Fuente J, Ceraul SM, Blouin EF, Almazán C. Capillary tube feeding system for studying tick-pathogen interactions of Dermacentor variabilis (Acari: Ixodidae) and Anaplasma marginale (Rickettsiales: Anaplasmataceae). J Med Entomol 2005; 42:864-74. [PMID: 16366000 DOI: 10.1093/jmedent/42.5.864] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A capillary tube feeding (CTF) system was adapted for studying the interaction between Dermacentor variabilis (Say) and the rickettsial cattle pathogen Anaplasma marginale Theiler. A. marginale undergoes a complex developmental cycle in ticks that begins in midguts and ends by transmission from salivary glands. In this CTF system, male D. variabilis were fed A. marginale-infected blood or cultured tick cells. Ticks that fed on highly rickettsemic calves developed midgut and salivary gland infections as detected by PCR, whereas ticks that were fed from capillary tubes on the same blood developed only midgut infections. An unexpected result of capillary tube feeding was that antibodies against the A. marginale adhesin, major surface protein la, enhanced midgut infections and caused cell culture-derived A. marginale to infect midguts. Another unexpected result was the infection of the midguts of the nonvector tick Amblyomma americanum (L.), after capillary tube feeding on infected bovine blood. The gut cell response of ticks to A. marginale, as determined from SDS-polyacrylamide gel electrophoresis protein profiles, did not differ when ticks were fed infected or uninfected cells from capillary tubes. Selected protein bands, as identified by tryptic digestion-mass spectrometry, contained mostly proteins of bovine origin, including bovine albumin, undigested alpha- and beta-chain hemoglobin and hemoglobin fragments. Although infection of ticks by A. marginale CTF system was not the same as infection by feeding on cattle, the results obtained demonstrated the potential use of this system for identifying aspects of pathogen-vector interactions that are not readily recognized in naturally feeding ticks.
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Affiliation(s)
- Katherine M Kocan
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078-2007, USA
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Coetzee JF, Apley MD, Kocan KM, Rurangirwa FR, Van Donkersgoed J. Comparison of three oxytetracycline regimes for the treatment of persistent Anaplasma marginale infections in beef cattle. Vet Parasitol 2005; 127:61-73. [PMID: 15675047 DOI: 10.1016/j.vetpar.2004.08.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Anaplasmosis, caused by the tick-borne rickettsia, Anaplasma marginale, is an economically important disease of cattle in the United States and worldwide. Cattle that recover from acute infection become carriers in which low or microscopically undetectable A. marginale rickettsemia persists. Tetracycline antimicrobials are currently the only drug used in the US for treatment of acute anaplasmosis. There are currently no drugs specifically licensed for elimination of persistent infections. This study tested the efficacy of three oxytetracycline treatment regimens to clear A. marginale from cattle that were persistently infected. Forty Angus x Simmental steers, aged 6-12 months were experimentally infected with A. marginale. After the steers recovered from acute infection, seroconverted, and were confirmed infected using nested PCR followed by DNA hybridization, the carrier status of each animal was ascertained by sub-inoculation of blood into a separate, splenectomized Holstein calf. The steers were then blocked by bodyweight and randomly assigned as follows to four treatment groups: Treatment A, 300 mg/ml solution of oxytetracycline (Tetradure LA-300, Merial Canada Inc.) administered at 30 mg/kg, by intramuscular (i.m.) injection on day 0; Treatment B, the same 300 mg/ml solution of oxytetracycline administered at 30 mg/kg, i.m. on day 0 and again on day 5; Treatment C, a 200 mg/ml solution of oxytetracycline (Liquamycin LA-200, Pfizer Animal Health) administered at 22 mg/kg, intravenously (i.v.), q 24 h for 5 days (a treatment dose that corresponds with current Office International des Epizooties (OIE) recommendations for treatment prior to export). The fourth group consisted of untreated infected control cattle. All steers were still nested PCR and cELISA positive at 60 days after treatment. Infection was confirmed by subinoculation of blood into a splenectomized Holstein calf. These results demonstrated that the treatment regimens tested failed to clear A. marginale infections in carrier cattle.
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Affiliation(s)
- Johann F Coetzee
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
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18
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Abstract
Continuous cell lines from the ticks Amblyomma variegatum, Boophilus decoloratus, Boophilus microplus, Hyalomma anatolicum anatolicum, Ixodes scapularis, Ixodes ricinus and Rhipicephalus appendiculatus were tested for ability to support growth of the rickettsial pathogen Ehrlichia (previously Cowdria) ruminantium. Five E.ruminantium isolates, from West Africa, South Africa and the French West Indies, were used. Twelve tick cell lines were inoculated with E.ruminantium derived either from cultures of a bovine endothelial cell strain designated BPC or from other tick cell lines. Successful infection resulted in either continuous growth (in which the pathogen/cell line system could be perpetuated through regular subculture on fresh, uninfected cells for many months or years) or finite growth (in which the pathogen disappeared after one or a few subcultures). Infection with E.ruminantium from BPC was established in I.scapularis, I.ricinus and A.variegatum cell lines; E.ruminantium was transferred from these infected cell lines to B.decoloratus, B.microplus and R. appendiculatus cell lines. H.a.anatolicum cells could not be infected with E.ruminantium by any procedure. All five E.ruminantium isolates grew continuously in at least one tick cell line at temperatures between 28 degrees C and 37 degrees C; three of the isolates were successfully re-established in BPC following prolonged maintenance in tick cells. This study demonstrates that E.ruminantium is not intrinsically restricted to growth in cells from ticks of the natural vector genus Amblyomma.
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Affiliation(s)
- L Bell-Sakyi
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, Scotland, UK
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Garcia-Garcia JC, de la Fuente J, Bell-Eunice G, Blouin EF, Kocan KM. Glycosylation of Anaplasma marginale major surface protein 1a and its putative role in adhesion to tick cells. Infect Immun 2004; 72:3022-30. [PMID: 15102815 PMCID: PMC387886 DOI: 10.1128/iai.72.5.3022-3030.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaplasma marginale, the causative agent of bovine anaplasmosis, is a tick-borne rickettsial pathogen of cattle that multiplies in erythrocytes and tick cells. Major surface protein 1a (MSP1a) and MSP1b form the MSP1 complex of A. marginale, which is involved in adhesion of the pathogen to host cells. In this study we tested the hypothesis that MSP1a and MSP1b were glycosylated, because the observed molecular weights of both proteins were greater than the deduced molecular masses. We further hypothesized that the glycosylation of MSP1a plays a role in adhesion of A. marginale to tick cells. Native and Escherichia coli-derived recombinant MSP1a and MSP1b proteins were shown by gas chromatography to be glycosylated and to contain neutral sugars. Glycosylation of MSP1a appeared to be mainly O-linked to Ser/Thr residues in the N-terminal repeated peptides. Glycosylation may play a role in adhesion of A. marginale to tick cells because chemical deglycosylation of MSP1a significantly reduced its adhesive properties. Although the MSP1a polypeptide backbone alone was adherent to tick cell extract, the glycans in the N-terminal repeats appeared to enhance binding and may cooperatively interact with one or more surface molecules on host cells. These results demonstrated that MSP1a and MSP1b are glycosylated and suggest that the glycosylation of MSP1a plays a role in the adhesion of A. marginale to tick cells.
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Affiliation(s)
- Jose C Garcia-Garcia
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078-2007, USA
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20
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Garcia-Garcia JC, de la Fuente J, Blouin EF, Johnson TJ, Halbur T, Onet VC, Saliki JT, Kocan KM. Differential expression of the msp1alpha gene of Anaplasma marginale occurs in bovine erythrocytes and tick cells. Vet Microbiol 2004; 98:261-72. [PMID: 15036535 DOI: 10.1016/j.vetmic.2003.10.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2003] [Revised: 10/14/2003] [Accepted: 10/14/2003] [Indexed: 11/17/2022]
Abstract
Major surface proteins (MSP) 1a and 1b of the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) are conserved on A. marginale derived from bovine erythrocytes and tick cells. MSP1a and MSP1b form the MSP1 complex and are adhesins involved in infection of host cells. While both MSP1a and MSP1b are adhesins for bovine erythrocytes, only MSP1a is an adhesin for cultured and native tick cells. These studies were initiated because antibody responses to MSP1a and MSP1b differed in cattle immunized with killed A. marginale derived from bovine erythrocytes or cultured tick cells. A strong antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived A. marginale, whereas cattle immunized with tick cell culture-derived A. marginale produced antibodies preferentially to MSP1b. The molecular basis of this differential antibody response was then studied using Western blot, confocal microscopy and reverse transcriptase (RT)-PCR. Whereas expression of MSP1b by A. marginale derived from both bovine and tick host cells was similar at the protein and RNA levels, expression of MSP1a by A. marginale in these cells differed. Low levels of MSP1a were observed in cultured tick cells and tick salivary glands, but high expression of MSP1a occurred on A. marginale derived from bovine erythrocytes. The analysis of the expression of the msp1alpha gene by RT-PCR suggests that the differential expression of MSP1a is regulated at the transcriptional level and may influence the infectivity of A. marginale for host cells. Variation in the expression of MSP1a may also contribute to phenotypic and antigenic changes in the pathogen.
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Affiliation(s)
- Jose C Garcia-Garcia
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
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21
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Garcia-Garcia JC, de la Fuente J, Kocan KM, Blouin EF, Halbur T, Onet VC, Saliki JT. Mapping of B-cell epitopes in the N-terminal repeated peptides of Anaplasma marginale major surface protein 1a and characterization of the humoral immune response of cattle immunized with recombinant and whole organism antigens. Vet Immunol Immunopathol 2004; 98:137-51. [PMID: 15010223 DOI: 10.1016/j.vetimm.2003.11.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 11/25/2003] [Accepted: 11/25/2003] [Indexed: 11/22/2022]
Abstract
Major surface protein (MSP) 1a of the genus type species Anaplasma marginale (Rickettsiales: Anaplasmataceae) together with MSP1b forms the MSP1 complex. MSP1a has been shown to be involved in adhesion, infection and tick transmission of A. marginale, as well as to contribute to protective immunity in cattle. A differential antibody response to MSP1a and MSP1b was observed in cattle immunized with A. marginale derived from bovine erythrocytes (anti-MSP1a response) or cultured tick cells (anti-MSP1b response). In this study, we further characterized the MSP1a antibody response of cattle using several immunogens, including recombinant MSP1a (rMSP1a) protein, erythrocyte- or tick cell culture-derived A. marginale, or a combination of tick cell culture-derived A. marginale and rMSP1a. The MSP1a antibody response to all these immunogens was directed primarily against the N-terminal region of MSP1a that contains tandemly repeated peptides, whereas low antibody levels were detected against the C-terminal portion. Linear B-cell epitopes of MSP1a were mapped using synthetic peptides representing the entire sequence of the protein that were prepared by SPOT synthesis technology. Only two peptides in the N-terminal repeats were recognized by sera from immunized cattle. These peptides shared the sequence SSAGGQQQESS, which is likely to contain the linear B-cell epitope that was recognized by the pools of bovine sera. The average differential of antibody titers against MSP1a minus those against MSP1b correlated with lower percent reductions in PCV. A preferential antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived, cell culture-derived plus rMSP1a or rMSP1a alone, and the percent reduction PCV was significantly lower in these cattle as compared with the other immunization groups. These results provide insight into the bovine antibody response against A. marginale and the role of MSP1a in protection of cattle against A. marginale infection.
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Affiliation(s)
- Jose C Garcia-Garcia
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, 250 McElroy Hall, Stillwater, OK 74078-2007, USA
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Abstract
Anaplasmosis, a tick-borne cattle disease caused by the rickettsia Anaplasma marginale, is endemic in tropical and subtropical areas of the world. The disease causes considerable economic loss to both the dairy and beef industries worldwide. Analyses of 16S rRNA, groESL, and surface proteins have resulted in the recent reclassification of the order Rickettsiales. The genus Anaplasma, of which A. marginale is the type species, now also includes A. bovis, A. platys, and A. phagocytophilum, which were previously known as Ehrlichia bovis, E. platys, and the E. phagocytophila group (which causes human granulocytic ehrlichiosis), respectively. Live and killed vaccines have been used for control of anaplasmosis, and both types of vaccines have advantages and disadvantages. These vaccines have been effective in preventing clinical anaplasmosis in cattle but have not blocked A. marginale infection. Thus, persistently infected cattle serve as a reservoir of infective blood for both mechanical transmission and infection of ticks. Advances in biochemical, immunologic, and molecular technologies during the last decade have been applied to research of A. marginale and related organisms. The recent development of a cell culture system for A. marginale provides a potential source of antigen for the development of improved killed and live vaccines, and the availability of cell culture-derived antigen would eliminate the use of cattle in vaccine production. Increased knowledge of A. marginale antigen repertoires and an improved understanding of bovine cellular and humoral immune responses to A. marginale, combined with the new technologies, should contribute to the development of more effective vaccines for control and prevention of anaplasmosis.
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Affiliation(s)
- Katherine M Kocan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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23
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Abstract
Ticks often cluster at preferred feeding sites on hosts, and the co-feeding of ticks at the same site has been shown to increase feeding success and the transmission of some pathogens. While the major route of infection of ticks with pathogens is via the bloodmeal during feeding on a parasitemic host, non-systemic transmission of viruses and spirochetes has been shown to occur from infected to uninfected ticks at common feeding sites on uninfected hosts. In this research, two separate studies were done using the tick-borne rickettsial pathogen of cattle, Anaplasma marginale. In one study we tested whether A. marginale could be transmitted non-systemically from infected to uninfected Dermacentor variabilis males while co-feeding on rabbits. Infection of ticks was determined by allowing them to transmission feed on susceptible cattle and by DNA probe and microscopy studies on salivary glands. In the second study, we tested whether the co-feeding of male and female ticks on parasitemic cattle would increase the acquisition and development of A. marginale in males. A. marginale infections in salivary glands were determined by quantitative PCR after the ticks were allowed to transmission feed on susceptible cattle. Non-systemic transmission of A. marginale did not occur from infected and uninfected ticks that fed at the same site on rabbits and, therefore, does not appear to be a means of A. marginale transmission. A. marginale infections in male ticks were not increased while co-feeding with females. Thus, co-feeding of adult Dermacentor spp. does not appear to influence the dynamics of A. marginale transmission.
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Affiliation(s)
- Katherine M Kocan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
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Blouin EF, Saliki JT, de la Fuente J, Garcia-Garcia JC, Kocan KM. Antibodies to Anaplasma marginale major surface proteins 1a and 1b inhibit infectivity for cultured tick cells. Vet Parasitol 2003; 111:247-60. [PMID: 12531299 DOI: 10.1016/s0304-4017(02)00378-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Major surface protein 1 (MSP1) of the cattle pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) is a complex of two proteins, MSP1a and MSP1b. Previous studies demonstrated that MSP1a and MSP1b are adhesins for bovine erythrocytes, while only MSP1a proved to be an adhesin for tick cells. In this study, a tick cell culture system for propagation of A. marginale was used to develop an infection inhibition assay for testing the ability of antisera to block infection of A. marginale for cultured tick cells. A. marginale derived from cell culture was incubated with various antisera prior to inoculation onto cell monolayers. The monolayers were harvested 7 days post-inoculation and A. marginale in the cultures was quantified using an antigen detection ELISA. Antisera tested in the infection inhibition assay were derived from persistently infected cattle, from cattle immunized with A. marginale purified from bovine erythrocytes, and from rabbits and cattle that were immunized with the recombinant MSP1a, MSP1b and MSP1 complex. Antibodies from cattle persistently infected with A. marginale, cattle immunized with A. marginale from bovine erythrocytes or cattle immunized with the recombinant MSP1 complex did not inhibit the infectivity of A. marginale for tick cells. Antiserum from rabbits immunized with MSP1a and MSP1b (individually or combined) reduced infection of both the Virginia and Oklahoma isolates of A. marginale for tick cells by 25-70%. Likewise, antisera from cattle immunized with recombinant MSP1a or MSP1b inhibited infection of tick cells by 26-37%. These results further confirm the role of MSP1 complex proteins in infection of tick cells. Lack of inhibition of infection by antisera from naturally infected cattle or cattle immunized with whole organisms suggests that the bovine immune response is not directed toward blocking infection of A. marginale for tick cells and may contribute to the continued infectivity of the pathogen for ticks.
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Affiliation(s)
- Edmour F Blouin
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, 250 McElroy Hall, Stillwater, OK 74078-2007, USA.
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de la Fuente J, Garcia-Garcia JC, Blouin EF, Kocan KM. Characterization of the functional domain of major surface protein 1a involved in adhesion of the rickettsia Anaplasma marginale to host cells. Vet Microbiol 2003; 91:265-83. [PMID: 12458174 DOI: 10.1016/s0378-1135(02)00309-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The major surface protein (MSP) 1a of the genus type species Anaplasma marginale (Rickettsiales: Anaplasmataceae) has been shown to mediate adhesion, infection and transmission of the organism, as well as to contribute to protective immunity in cattle. MSP1a contains a variable number of tandemly repeated peptides in the amino-terminal region, while the remainder of the protein is highly conserved among isolates. The number of repeats varies among geographic isolates of A. marginale but is constant within an isolate and has been used as a stable genetic marker of isolate identity. Because the sequence of the tandem repeats is the most variable part of the protein among isolates, this region of the protein is most likely to be involved in adhesion to host cells, a prerequisite to infection. The purpose of this study was to characterize the organization and function of the MSP1a tandem repeats of A. marginale in adhesion to host cells. We demonstrated by use of recombinant mutant proteins that the tandemly repeated region of MSP1a was necessary and sufficient to mediate adhesion of MSP1a to tick cells and bovine erythrocytes. Synthetic peptides representing the predominant sequences of individual repeats were tested for their adhesive capacity for tick cell extract (TCE). Peptides containing acidic amino acids D or E at position 20 bound to TCE, while peptides with a G as the 20th amino acid were not adhesive to TCE. Antibodies produced in rabbits against a synthetic repeat peptide neutralized A. marginale infection of cultured tick cells, and the neutralization observed was similar to that effected by antibodies produced against the whole MSP1a recombinant protein. Analysis of tandemly repeated MSP1a peptides of several geographic isolates of A. marginale revealed a complex relationship between the msp1alpha genotype and the tick-transmissible phenotype of the isolate and suggested that both the sequence and conformation of the repeated peptides influenced the adhesive properties of MSP1a. These studies demonstrated that the tandemly repeated region of the protein mediates the adhesive function of MSP1a.
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Affiliation(s)
- José de la Fuente
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, 250 McElroy Hall, 74078-2007, Stillwater, OK, USA.
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Abstract
Anaplasmataceae, the causative agents of anaplasmosis and ehrlichiosis, persist in the bloodstream of their mammalian hosts, allowing acquisition and transmission by tick vectors. Anaplasma marginale establishes persistent infection characterized by sequential cycles of rickettsaemia in which new antigenic variants emerge. The two most immunodominant outer membrane proteins, MSP2 and MSP3, are paralogues, each encoded by a distinct family of related genes. This study demonstrates that, although the two gene families have diverged substantially, each has maintained a similar mechanism to generate structurally and antigenically polymorphic surface antigens. Like MSP2, MSP3 is expressed from a single locus in which variation of the expressed msp3 gene is generated by recombination using msp3 pseudogenes. Each of the msp3 pseudogenes encodes a unique central variable region (CVR) flanked by conserved 5' and 3' regions. Changes in the CVR of the expressed msp3, concomitant with invariance of the pseudogenes, indicate that expression site variation is generated using gene conversion. A. marginale thus maintains two large, separate systems within its small genome to generate antigenic variation of its surface proteins, while analogous structural elements indicate a common mechanism.
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Affiliation(s)
- Patrick F M Meeus
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, 2015 SW 16th Avenue, Gainesville, FL 32611-0880, USA.
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de la Fuente J, Kocan KM, Garcia-Garcia JC, Blouin EF, Claypool PL, Saliki JT. Vaccination of cattle with Anaplasma marginale derived from tick cell culture and bovine erythrocytes followed by challenge-exposure with infected ticks. Vet Microbiol 2002; 89:239-251. [PMID: 12243900 DOI: 10.1016/s0378-1135(02)00206-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Anaplasmosis, a hemolytic disease of cattle caused by the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) has been controlled using killed vaccines made with antigen harvested from infected bovine erythrocytes. We recently developed a cell culture system for propagation of A. marginale in a continuous tick cell line. In this study, we performed a cattle trial to compare the bovine response to vaccination with A. marginale harvested from tick cell culture or bovine erythrocytes. All immunized and control cattle were then challenge-exposed by allowing male Dermacentor variabilis infected with A. marginale to feed and transmit the pathogen. Nine yearling cattle (three per group) were used for this study and were immunized with cell culture-derived A. marginale, erythrocyte-derived A. marginale or received adjuvant only to serve as controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale and three immunizations were administered at weeks 1, 4 and 6. At week 8, cattle were challenge-exposed by allowing 60 D. variabilis male that were infected with A. marginale as adults to feed on the cattle. Antibody responses of cattle against major surface proteins (MSP) 1a, 1b and 5, as determined by ELISAs, peaked 2 weeks after the last immunization. Cattle immunized with infected IDE8 cell-derived antigens had a preferential recognition for MSP1b while cattle immunized with erythrocyte-derived antigens had a preferential recognition for MSP1a. Protection efficacy was evaluated using the percent infected erythrocytes (PPE), the packed cell volume (PCV), and the prepatent period. A. marginale-immunized cattle showed lower PPE and higher PCV values when compared to control animals and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.
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Affiliation(s)
- José de la Fuente
- Department of Veterinary Pathobiology, College of Veterinary Medicine, 250 McElory Hall, Oklahoma State University, Stillwater, OK 74078-2007, USA.
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Abstract
Infections of the tick-borne ehrlichial pathogen, Anaplasma marginale, in cattle have been controlled, in part, by administration of low doses of tetracycline. Recently, a cell culture system was developed for A. marginale using a tick cell line derived from embryonic Ixodes scapularis. This study was designed to determine the effect of tetracycline on A. marginale propagated in a tick cell culture assay. Various concentrations of tetracycline (0, 0.01, 0.10, 1.0, 5, 10, 20 or 100 microg/ml) were added in medium to cultures 48h after cell monolayers were inoculated with A. marginale. A. marginale growth in the drug treated and control cultures was subsequently evaluated by indirect ELISA at 7 days post-infection (PI) and daily by light and electron microscopy (LM and EM). Infectivity of the culture-derived A. marginale was determined by inoculation of susceptible cattle with treated and untreated control cultures. Tetracycline doses of 5, 10, 20 and 100 microg/ml resulted in significant inhibition of A. marginale growth as determined by ELISA. Morphologic deterioration of Anaplasma, as determined by LM and EM, occurred in cultures treated with the same drug concentrations. A. marginale replication, inhibited in cultures treated on days 2-6 PI with 20 microg/ml tetracycline, was not apparent 96 days after antibiotic removal. Infected cell cultures treated with medium containing 20 microg/ml tetracycline proved to be non-infective when inoculated into susceptible splenectomized calves. All parameters studied herein demonstrated that tetracycline killed A. marginale in cultured tick cells. The Anaplasma-tick cell culture drug assay therefore, would be useful for screening and evaluating novel antibiotics for control of anaplasmosis.
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Affiliation(s)
- Edmour F Blouin
- Department of Veterinary Pathobiology, 250 McElroy Hall, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
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de la Fuente J, Garcia-Garcia JC, Blouin EF, Saliki JT, Kocan KM. Infection of tick cells and bovine erythrocytes with one genotype of the intracellular ehrlichia Anaplasma marginale excludes infection with other genotypes. Clin Diagn Lab Immunol 2002; 9:658-68. [PMID: 11986275 PMCID: PMC119989 DOI: 10.1128/cdli.9.3.658-668.2002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2001] [Revised: 12/14/2001] [Accepted: 01/22/2002] [Indexed: 11/20/2022]
Abstract
Anaplasma marginale, a tick-borne rickettsial pathogen of cattle, is endemic in several areas of the United States. Many geographic isolates of A. marginale that occur in the United States are characterized by the major surface protein 1a, which varies in sequence and molecular weight due to different numbers of tandem repeats of 28 or 29 amino acids. Recent studies (G. H. Palmer, F. R. Rurangirwa, and T. F. McElwain, J. Clin. Microbiol. 39:631-635, 2001) of an A. marginale-infected herd of cattle in an area of endemicity demonstrated that multiple msp1alpha genotypes were present but that only one genotype was found per individual bovine. These findings suggested that infection of cattle with other genotypes was excluded. The present study was undertaken to confirm the phenomenon of infection exclusion of A. marginale genotypes in infected bovine erythrocytes and cultured tick cells. Two tick-transmissible isolates of A. marginale, one from Virginia and one from Oklahoma, were used for these studies. In two separate trials, cattle inoculated with equal doses of the two isolates developed infection with only one genotype. Tick cell cultures inoculated with equal doses of the two isolates became infected with only the Virginia isolate of A. marginale. When cultures were inoculated with different ratios of the Oklahoma and Virginia isolates of A. marginale, the isolate inoculated in the higher ratio became established and excluded infection with the other. When cultures with established infections of one isolate were subsequently infected with the other, only the established isolate was detected. We documented infection exclusion during initial infection in cell culture by labeling each isolate with a different fluorescent dye. After 2 days in culture, only a single isolate was detected per cell by fluorescence microscopy. Finally, when Anaplasma ovis infections were established in cultures that were subsequently inoculated with the Virginia or Oklahoma isolate of A. marginale, A. marginale infection was excluded. These studies confirm that infection exclusion occurs with A. marginale in bovine erythrocytes and tick cells, resulting in the establishment of only one genotype, and appears to be the first report of infection exclusion for Anaplasma and Ehrlichia species.
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Affiliation(s)
- José de la Fuente
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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Bowie MV, de la Fuente J, Kocan KM, Blouin EF, Barbet AF. Conservation of major surface protein 1 genes of Anaplasma marginale during cyclic transmission between ticks and cattle. Gene 2002; 282:95-102. [PMID: 11814681 DOI: 10.1016/s0378-1119(01)00845-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Bovine anaplasmosis is a rickettsial disease of world-wide economic importance caused by Anaplasma marginale. Several major surface proteins with conserved gene sequences have been examined as potential candidates for vaccines and/or diagnostic assays. Major surface protein 1 (MSP1) is composed of polypeptides MSP1a and MSP1b. MSP1a is expressed from the single copy gene msp1 alpha and MSP1b is expressed by members of the msp1 beta multigene family. In order to determine if the msp1 genes are conserved, primers specific for msp1 alpha, msp1 beta(1), and msp1 beta(2) genes were synthesized and used to amplify msp1 sequences of A. marginale from tick cell cultures, from cattle during acute and chronic infections and from salivary glands of Dermacentor variabilis. Protein sequences of MSP1a, MSP1b(1) and MSP1b(2) were conserved during the life cycle of the parasite. No amino acid changes were observed in MSP1a. However, small variations were observed in the MSP1b(1) and MSP1b(2) protein sequences, which could be attributed to recombination, selection for sub-populations of A. marginale in the vertebrate host and/or PCR errors. Several isolate-specific sequences were also observed. Based on the information obtained in this study, the MSP1 protein appears to be fairly well conserved and a potential vaccine candidate.
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Affiliation(s)
- Michael V Bowie
- Department of Pathobiology, University of Florida, PO Box 110880, Gainesville, FL 32611-0880, USA.
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Kocan KM, Halbur T, Blouin EF, Onet V, de la Fuente J, Garcia-Garcia JC, Saliki JT. Immunization of cattle with Anaplasma marginale derived from tick cell culture. Vet Parasitol 2001; 102:151-61. [PMID: 11705661 DOI: 10.1016/s0304-4017(01)00519-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Anaplasmosis is a hemolytic disease of cattle caused by the ehrlichial tick-borne pathogen Anaplasma marginale. Killed vaccines used for control of anaplasmosis in the US used antigen harvested from infected bovine erythrocytes which was often contaminated with bovine cells and other pathogens. In this study, we performed an initial cattle trial to test A. marginale harvested from tick cell culture as an immunogen for cattle. Eleven yearling Holstein cattle were immunized with the cell culture-derived A. marginale and 11 cattle were non-immunized contact controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale in an oil-based adjuvant. Two immunizations were administered subcutaneously 4 weeks apart and the cattle were challenge-exposed 10 weeks after the second immunization with A. marginale infected blood. Maximum antibody levels as determined by an A. marginale specific competitive ELISA were observed 2 weeks after the last immunization. Antibody responses against major surface proteins (MSPs) 1a and 1beta1 were also characterized and immunized cattle demonstrated a preferential recognition for MSP1beta1. Cattle immunized with the cell culture-derived A. marginale had a significantly lower percent reduction in the packed cell volume (P<0.05) after challenge exposure as compared with the controls and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.
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Affiliation(s)
- K M Kocan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-2007, USA.
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de la Fuente J, Van Den Bussche RA, Kocan KM. Molecular phylogeny and biogeography of North American isolates of Anaplasma marginale (Rickettsiaceae: Ehrlichieae). Vet Parasitol 2001; 97:65-76. [PMID: 11337128 DOI: 10.1016/s0304-4017(01)00378-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Anaplasma marginale (A. marginale) is a tick-borne ehrlichial pathogen of cattle that causes the disease anaplasmosis. Six major surface proteins (MSPs) have been identified on A. marginale from cattle and ticks of which three, MSP1a, MSP4 and MSP5, are from single genes and do not vary within isolates. The other three, MSP1b, MSP2 and MSP3, are from multigene families and may vary antigenically in persistently infected cattle. Several geographic isolates have been identified in the United States which differ in morphology, protein sequence and antigenic properties. An identifying characteristic of A. marginale isolates is the molecular weight of MSP1a which varies in size among isolates due to different numbers of tandemly repeated 28-29 amino acid peptides. For these studies, genes coding for A. marginale MSP1a and MSP4, msp1alpha and msp4, respectively, from nine North American isolates were sequenced for phylogenetic analysis. The phylogenetic analysis strongly supports the existence of a south-eastern clade of A. marginale comprised of Virginia and Florida isolates. Analysis of 16S rDNA fragment sequences from the A. marginale tick vector, Dermacentor variabilis, from various areas of the United States was used to evaluate possible vector-parasite co-evolution. Our phylogenetic analysis supports identity between the most parsimonious tree from the A. marginale MSP gene data and the tree that reflected the western and eastern clades of D. variabilis. These phylogenetic analyses provide information that may be important to consider when developing control strategies for anaplasmosis in the United States.
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Affiliation(s)
- J de la Fuente
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
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Barbet AF, Yi J, Lundgren A, McEwen BR, Blouin EF, Kocan KM. Antigenic variation of Anaplasma marginale: major surface protein 2 diversity during cyclic transmission between ticks and cattle. Infect Immun 2001; 69:3057-66. [PMID: 11292724 PMCID: PMC98260 DOI: 10.1128/iai.69.5.3057-3066.2001] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rickettsial pathogen Anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (MSP2), involved in antigenic variation and long-term persistence of the organism in carrier animals. MSP2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic B-cell epitopes that induce variant-specific antibodies during infection. Previously, we have shown that MSP2 is encoded on a polycistronic mRNA transcript in erythrocyte stages of A. marginale and defined the structure of the genomic expression site for this transcript. In this study, we show that the same expression site is utilized in stages of A. marginale infecting tick salivary glands. We also analyzed the variability of this genomic expression site in Oklahoma strain A. marginale transmitted from in vitro cultures to cattle and between cattle and ticks. The structure of the expression site and flanking regions was conserved except for sequence that encoded the MSP2 hypervariable region. At least three different MSP2 variants were encoded in each A. marginale population. The major sequence variants did not change on passage of A. marginale between culture, acute erythrocyte stage infections, and tick salivary glands but did change during persistent infections of cattle. The variant types found in tick salivary glands most closely resembled those present in bovine blood at the time of acquisition of infection, whether infection was acquired from an acute or from a persistent rickettsemia. These variations in structure of an expression site for a major, immunoprotective outer membrane protein have important implications for vaccine development and for obtaining an improved understanding of the mechanisms of persistence of ehrlichial infections in humans, domestic animals, and reservoir hosts.
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Affiliation(s)
- A F Barbet
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32611, USA.
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de la Fuente J, Garcia-Garcia JC, Blouin EF, Kocan KM. Differential adhesion of major surface proteins 1a and 1b of the ehrlichial cattle pathogen Anaplasma marginale to bovine erythrocytes and tick cells. Int J Parasitol 2001; 31:145-53. [PMID: 11239934 DOI: 10.1016/s0020-7519(00)00162-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Anaplasma marginale is a tick-borne ehrlichial pathogen of cattle for which six major surface proteins (MSPs) have been described. The MSP1 complex, a heterodimer composed of MSP1a and MSP1b, was shown to induce a protective immune response in cattle and both proteins have been identified as putative adhesins for bovine erythrocytes. In this study the role of MSP1a and MSP1b as adhesins for bovine erythrocytes and tick cells was defined. msp1alpha and msp1beta1 genes from the Oklahoma isolate of A. marginale were cloned and expressed in Escherichia coli K-12 under the control of endogenous and tac promoters for both low and high level protein expression. Expression of the recombinant polypeptides was confirmed and localised on the surface of transformed E. coli. The adhesion properties of MSP1a and MSP1b were determined by allowing recombinant E. coli expressing these surface polypetides to react with bovine erythrocytes, Dermacentor variabilis gut cells and cultured tick cells derived from embryonic Ixodes scapularis. Adhesion of the recombinant E. coli to the three cell types was determined using recovery adhesion and microtiter haemagglutination assays, and by light and electron microscopy. MSP1a was shown by all methods tested to be an adhesin for bovine erythrocytes and both native and cultured tick cells. In contrast, recombinant E. coli expressing MSP1b adhered only to bovine erythrocytes and not to tick cells. When low expression vectors were used, single E. coli expressing MSP1a was seen adhered to individual tick cells while reaction of tick cells with the E. coli/MSP1a/high expression vector resulted in adhesion of multiple bacteria per cell. With electron microscopy, fusion of E. coli cell membranes expressing MSP1a or MSP1b with erythrocyte membranes was observed, as well as fusion of tick cell membranes with E. coli membranes expressing MSP1a. These studies demonstrated differential adhesion for MSP1a and MSP1b for which MSP1a is an A. marginale adhesin for both bovine erythrocytes and tick cells while MSP1b is an adhesin only for bovine erythrocytes. The role of the MSP1 complex, therefore, appears to vary among vertebrate and invertebrate hosts.
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Affiliation(s)
- J de la Fuente
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
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