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Kruglova M, Nikitin N, Evtushenko E, Matveeva I, Mazurov A, Pavlenko I, Popova V, Bogomolova O, Vasilyev S, Markova E, Fedorov Y. Inactivated Flagellin-Containing Vaccine Efficacy against Ovine Enzootic Abortion. Pathogens 2024; 13:277. [PMID: 38668231 PMCID: PMC11053442 DOI: 10.3390/pathogens13040277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/29/2024] Open
Abstract
Chlamydia abortus is the etiological agent of abortion and fetal loss in sheep, goats and bovine cattle in many countries. Even though commercially available vaccines can reduce the incidence in sheep, the development of new, safe, and effective vaccines remains high on the agenda. In this study, an evaluation was made of the efficacy of a vaccine candidate, an inactivated antigen based on the extract of outer membrane proteins of a C. abortus strain known as Chlamydia VNITIBP-21, in combination with recombinant flagellin as an adjuvant. Pregnant sheep (n = 43) were divided into three groups: an experimental vaccinated group, a control infected group and a control non-infected group. The sheep were vaccinated twice, with an interval of 3 weeks, then infected with the homologous virulent strain of Chlamydia abortus on pregnancy day 75. The vaccine candidate reduced C. abortus shedding in vaginal swabs considerably, in comparison with the control group. In addition, ewes in the experimental group experienced no abortions, while those in the control group experienced instances of abortion, as well as births of weak and nonviable lambs. The findings show that the vaccine candidate proved itself to be promising in combatting the agent of ovine abortion and fetal loss.
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Affiliation(s)
- Maria Kruglova
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Nikolai Nikitin
- Department of Virology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Ekaterina Evtushenko
- Department of Virology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Irina Matveeva
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Aleksandr Mazurov
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Igor Pavlenko
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Vera Popova
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Olesya Bogomolova
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Stepan Vasilyev
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Evgeniya Markova
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
| | - Yuri Fedorov
- All-Russian Scientific Research and Technological Institute of Biological Industry, Biocombinat, 141142 Moscow, Russia
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2
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Rockey DD, Wang X, Debrine A, Grieshaber N, Grieshaber SS. Metabolic dormancy in Chlamydia trachomatis treated with different antibiotics. Infect Immun 2024; 92:e0033923. [PMID: 38214508 PMCID: PMC10863404 DOI: 10.1128/iai.00339-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/11/2023] [Indexed: 01/13/2024] Open
Abstract
Diseases caused by Chlamydia spp. are often associated with persistent infections. Chlamydial persistence is commonly associated with a unique non-infectious intracellular developmental form, termed an aberrant form. Although infectious chlamydiae can be cultured consistently in cells stressed to aberrancy, their role in persistence is not clear. Recovery from antibiotic stress was explored as a model to determine how survival of non-aberrant chlamydiae, in the presence of fully inhibitory drug concentrations, may participate in persistence. Assays included incubation in quinolones, tetracyclines, or chloramphenicol for differing lengths of time, followed by an extended recovery period in antibiotic-free media. Culturable elementary bodies were not detected during treatment with each antibiotic, but viable and culturable Chlamydia trachomatis emerged after the drug was removed. Time-lapse imaging of live, antibiotic-treated infected cells identified metabolically dormant developmental forms within cells that emerged to form typical productive inclusions. The effects of the increasing concentration of most tested antibiotics led to predictable inhibitory activity, in which the survival rate decreased with increasing drug concentration. In contrast, in fluoroquinolone-treated cells, there was a paradoxical increase in productive development that was directly correlated with drug concentration and inversely associated with aberrant form production. This model system uncovers a unique chlamydial persistence pathway that does not involve the chlamydial aberrant form. The association between productive latency and metabolic dormancy is consistent with models for many bacterial species and may lead to a different interpretation of mechanisms of chlamydial persistence in patients.IMPORTANCEThe life history of most pathogens within the genus Chlamydia relies on lengthy persistence in the host. The most generally accepted model for Chlamydia spp. persistence involves an unusual developmental stage, termed the aberrant form, which arises during conditions that mimic a stressful host environment. In this work, we provide an alternate model for chlamydial persistence in the face of antibiotic stress. This model may be relevant to antibiotic treatment failures in patients infected with C. trachomatis.
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Affiliation(s)
- Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Xisheng Wang
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Abigail Debrine
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Nicole Grieshaber
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
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Richardson S, Bell CR, Medhavi F, Tanner T, Lundy S, Omosun Y, Igietseme JU, Eko FO. A novel cold-chain free VCG-based subunit vaccine protects against Chlamydia abortus-induced neonatal mortality in a pregnant mouse model. Front Immunol 2023; 14:1243743. [PMID: 37915580 PMCID: PMC10616880 DOI: 10.3389/fimmu.2023.1243743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
Chlamydia abortus (Cab) causes spontaneous abortion and neonatal mortality in infected ruminants and pregnant women. Most Cab infections are asymptomatic, although they can be treated with antibiotics, signifying that control of these infections may require alternative strategies, including the use of effective vaccines. However, the limitations imposed by live attenuated and inactivated vaccines further suggest that employment of subunit vaccines may need to be considered. The efficacy of a newly generated Vibrio cholerae ghost (rVCG)-based subunit vaccine harboring the N-terminal portion of the Cab Pmp18D protein (rVCG-Pmp18.3) in preventing Cab-induced abortion or neonatal mortality was evaluated in pregnant mice. Mice were intranasally (IN) immunized and boosted twice, 2 weeks apart with the vaccine, and immunized and unimmunized mice were caged with males 4 weeks postimmunization. The mice were then infected either IN or transcervically (TC) 10 days after pregnancy, and the fertility rate was determined 7 days postpartum. Eight days after delivery, the mice were sacrificed, and Cab infectivity in the lungs and spleens was evaluated by culturing tissue homogenates in tissue culture. Our results demonstrated that the vaccine induced immune effectors that mediated complete clearance of infection in the lungs and significantly reduced Cab infectivity in the spleen following IN immunization. Vaccine immunization also afforded protection against Cab-induced upper genital tract pathology (uterine dilation). Furthermore, while there was no incidence of abortion in both immunized and unimmunized mice, immunized mice were completely protected against neonatal mortality compared to unimmunized infected controls, which lost a significant percentage of their litter 7 days postpartum. Our results establish the capability of the rVCG-Pmp18.3 vaccine to prevent infection in the lungs (mucosal) and spleen (systemic) and protect mice from Cab-induced tubal pathologies and neonatal mortality, a hallmark of Cab infection in ruminants. To advance the commercial potential of this vaccine, future studies will optimize the antigen dose and the number of vaccine doses required for protection of ruminants.
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Affiliation(s)
- Shakyra Richardson
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Courtnee R. Bell
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Fnu Medhavi
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Tayhlor Tanner
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Stephanie Lundy
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Yusuf Omosun
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Joseph U. Igietseme
- National Center for Emerging Zoonotic and Infectious Diseases, Center for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Francis O. Eko
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
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Turin L, Surini S, Wheelhouse N, Rocchi MS. Recent advances and public health implications for environmental exposure to Chlamydia abortus: from enzootic to zoonotic disease. Vet Res 2022; 53:37. [PMID: 35642008 PMCID: PMC9152823 DOI: 10.1186/s13567-022-01052-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/29/2022] [Indexed: 11/24/2022] Open
Abstract
Environmental transmission of Chlamydia abortus as a result of enzootic disease or disease outbreaks and the threats posed by this pathogen has been previously reported, however a state-of-the-science review of these reports and the identification of future research priorities in this area is still lacking. This study provides an overview of the current knowledge of host–pathogen–environment interactions, addressing public health risks and identifying critical questions and research gaps. We performed a systematic PubMed and Web of Science search for publications related to Chlamydia abortus in the past four decades, and we reviewed and combined the evidence critically discussing and commenting the results. A total of 182 studies, 5 chapters of specific books and the “OIE terrestrial manual” were included in this review. There were substantial variations between the studies in topic addressed and experimental design. Overall, the literature largely supports the crucial role played by environmental exposure on the acquisition of zoonotic disease caused by Chlamydia abortus. We also identify the paucity of information related to interspecies transmission and pathogen adaptation in relation to environmental dissemination and zoonotic risk. This analysis further highlights the need for additional research given that environmental transmission represents a serious risk not only to susceptible patients (pregnant women and immunocompromised individuals), but also for other species including wildlife.
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Affiliation(s)
- Lauretta Turin
- Department of Veterinary Medicine (DIMEVET), University of Milan, Milan, Italy.
| | - Sara Surini
- Department of Veterinary Medicine (DIMEVET), University of Milan, Milan, Italy
| | - Nick Wheelhouse
- School of Applied Sciences, Edinburgh Napier University, Sighthill Court, Edinburgh, EH11 4BN, UK
| | - Mara Silvia Rocchi
- Moredun Research Institute, Bush Loan, Pentlands Science Park, Penicuik, EH26 0PZ, Scotland, UK
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5
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Livingstone M, Wattegedera SR, Palarea-Albaladejo J, Aitchison K, Corbett C, Sait M, Wilson K, Chianini F, Rocchi MS, Wheelhouse N, Entrican G, Longbottom D. Efficacy of Two Chlamydia abortus Subcellular Vaccines in a Pregnant Ewe Challenge Model for Ovine Enzootic Abortion. Vaccines (Basel) 2021; 9:vaccines9080898. [PMID: 34452023 PMCID: PMC8402522 DOI: 10.3390/vaccines9080898] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
Chlamydia abortus, the aetiological agent of enzootic abortion of ewes, is a major cause of reproductive loss in small ruminants worldwide, accounting for significant economic losses to the farming industry. Disease can be managed through the use of commercial inactivated or live whole organism-based vaccines, although both have limitations particularly in terms of efficacy, safety and disease-associated outbreaks. Here we report a comparison of two experimental vaccines (chlamydial outer membrane complex (COMC) and octyl glucoside (OG)-COMC) based on detergent extracted outer membrane preparations of C. abortus and delivered as prime-boost immunisations, with the commercial live vaccine Cevac® Chlamydia in a pregnant sheep challenge model. No abortions occurred in either experimental vaccine group, while a single abortion occurred in the commercial vaccine group. Bacterial shedding, as a measure of potential risk of transmission of infection to naïve animals, was lowest in the COMC vaccinated group, with reductions of 87.5%, 86.4% and 74% observed for the COMC, OG-COMC and live commercial vaccine groups, respectively, compared to the unvaccinated challenge control group. The results show that the COMC vaccine performed the best and is a safer efficacious alternative to the commercial vaccines. However, to improve commercial viability, future studies should optimise the antigen dose and number of inoculations required.
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Affiliation(s)
- Morag Livingstone
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Sean Ranjan Wattegedera
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | | | - Kevin Aitchison
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Cecilia Corbett
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Michelle Sait
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Kim Wilson
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Francesca Chianini
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Mara Silvia Rocchi
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Nicholas Wheelhouse
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Gary Entrican
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - David Longbottom
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
- Correspondence:
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6
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Montbrau C, Fontseca M, March R, Sitja M, Benavides J, Ortega N, Caro MR, Salinas J. Evaluation of the Efficacy of a New Commercially Available Inactivated Vaccine Against Ovine Enzootic Abortion. Front Vet Sci 2020; 7:593. [PMID: 33102549 PMCID: PMC7499823 DOI: 10.3389/fvets.2020.00593] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/23/2020] [Indexed: 01/11/2023] Open
Abstract
Ovine enzootic abortion (OEA), caused by Chlamydia abortus, is an economically important disease in many countries. Inactivated vaccines have been used for many years as they induce immunity in sheep, although outbreaks of abortions have been described in vaccinated flocks. In addition, there is a commercially available live attenuated vaccine that provides good protective results. Recently however, reports question the attenuation of this vaccine and associate it with the appearance of outbreaks of OEA in vaccinated flocks. In the present study, a recently commercialized inactivated vaccine (INMEVA®; Laboratorios Hipra S.A., Amer, Spain) has been evaluated using mouse and sheep experimental models. In the mouse models (non-pregnant and pregnant models), the efficacy of INMEVA vaccine has been compared to an unvaccinated control group and to an experimental inactivated vaccine considered as a positive protection control (UMU vaccine). In the non- pregnant model, the UMU vaccine was more effective than the INMEVA vaccine regarding the impact on body weight or the presence of C. abortus in the liver, but both vaccinated groups (UMU and INMEVA) had significantly lower C. abortus in the liver compared to the control group. In the pregnant model in terms of reproductive failures, pups per mouse or the presence of C. abortus in the liver or uterus, no significant differences were found between both vaccines, inducing protection compared to the control group. In the ovine pregnant model, where INMEVA vaccine was compared only to an unvaccinated group, the results indicate that this new commercial vaccine is safe and provides a suitable level of protection against an experimental challenge with C. abortus. A 75% reduction in reproductive disorders, 55% reduction in animals with C. abortus shedding on day of parturition/abortion, and a significant reduction of the average amount of chlamydial shedding from parturition/abortion over the next 21 days was observed, in relation to the infected control group. The results suggest that this vaccine is adequate for the control and prevention of OEA; however, future studies are necessary to elucidate the type of protective immune response that it induces.
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Affiliation(s)
| | | | | | | | - Julio Benavides
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain
| | - Nieves Ortega
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
| | - María Rosa Caro
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
| | - Jesús Salinas
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
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7
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Wattegedera SR, Livingstone M, Maley S, Rocchi M, Lee S, Pang Y, Wheelhouse NM, Aitchison K, Palarea-Albaladejo J, Buxton D, Longbottom D, Entrican G. Defining immune correlates during latent and active chlamydial infection in sheep. Vet Res 2020; 51:75. [PMID: 32487248 PMCID: PMC7268686 DOI: 10.1186/s13567-020-00798-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/11/2020] [Indexed: 12/31/2022] Open
Abstract
Ovine enzootic abortion (OEA) caused by the obligate intracellular bacterial pathogen Chlamydia abortus (C. abortus), is an endemic disease in most sheep-rearing countries worldwide. Following infection, C. abortus establishes a complex host-pathogen interaction with a latent phase in non-pregnant sheep followed by an active disease phase in the placenta during pregnancy leading to OEA. Improved knowledge of the host-pathogen interactions at these different phases of disease will accelerate the development of new diagnostic tests and vaccines to control OEA. Current evidence indicates that cellular immunity is essential for controlling C. abortus infection. We have previously described a model of mucosal (intranasal) infection of non-pregnant sheep with C. abortus that replicates the latent and active phases of OEA. We have investigated antigen-specific recall responses of peripheral blood mononuclear cells (PBMC) in sheep infected with C. abortus via the intranasal route to determine how these change during the latent and active phases of disease. By analysing cytokines associated with the major CD4+ve Thelper (Th) cell subsets (Interferon-gamma (IFN-γ)/Th1; Interleukin (IL)-4/Th2; IL-17A/Th17; IL-10/Tregulatory), we show that there is selective activation of PBMC producing IFN-γ and/or IL-10 during the latent phase following infection. These cytokines are also elevated during the active disease phase and while they are produced by sheep that are protected from OEA, they are also produced by sheep that abort, highlighting the difficulties in finding specific cellular immunological correlates of protection for complex intracellular pathogens.
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Affiliation(s)
- Sean R. Wattegedera
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Morag Livingstone
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Stephen Maley
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Mara Rocchi
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Susan Lee
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Yvonne Pang
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Nick M. Wheelhouse
- School of Applied Sciences, Napier University, Edinburgh, Scotland EH11 4BN UK
| | - Kevin Aitchison
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Javier Palarea-Albaladejo
- Biomathematics and Statistics Scotland, JCMB, The King’s Buildings, Peter Guthrie Tait Road, Edinburgh, Scotland EH9 3FD UK
| | - David Buxton
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - David Longbottom
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
| | - Gary Entrican
- Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland EH26 0PZ UK
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, Scotland EH25 9RG UK
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8
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O'Neill LM, Keane OM, Ross PJ, Nally JE, Seshu J, Markey B. Evaluation of protective and immune responses following vaccination with recombinant MIP and CPAF from Chlamydia abortus as novel vaccines for enzootic abortion of ewes. Vaccine 2019; 37:5428-5438. [PMID: 31375438 DOI: 10.1016/j.vaccine.2019.06.088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 06/26/2019] [Accepted: 06/28/2019] [Indexed: 11/18/2022]
Abstract
MIP and CPAF from Chlamydia have been shown to be effective in inducing immune responses important in clearing chlamydial infections. This study evaluates the protection conferred by MIP and CPAF as novel vaccines in pregnant C. abortus challenged ewes. Fifty C. abortus sero-negative sheep were randomly allocated into 5 groups of 10 according to the treatment they were to receive (1) 100 µg of MBP-MIP (2) 100 µg CPAF (3) 50 µg MBP-MIP and 50 µg CPAF (4) Tris-buffer (negative control) (5) Enzovax (positive control). Booster inoculations were administered 3 weeks after primary inoculations. Blood samples were taken pre-vaccination and weekly for 5 weeks. Five months after vaccination the ewes were mated. Pregnant ewes were then challenged on day 90 of gestation. Blood samples taken at four time-points post challenge were analysed for IFNγ levels, TNFα and IL-10 expression and anti-chlamydial antibody levels. Vaginal swabs, placental and foetal tissue and bacterial shedding were analysed using qPCR to quantify levels of C. abortus. Enzovax was 100% effective with no abortions occurring. The MIP/CPAF combined vaccine offered the greatest protection of the novel vaccines with 67% of ewes giving birth to one or more live lambs equating to a 50% vaccine efficacy rate. MIP and CPAF administered singly did not confer protection. Enzovax and MIP/CPAF vaccinated ewes had longer gestations and lambs with higher birth weights than negative control ewes. Aborting ewes shed higher numbers of C. abortus than ewes that had live lambs, all vaccinated ewes demonstrated lower levels of bacterial shedding than negative control ewes with Enzovax ewes shedding significantly fewer bacteria. Ewes that went on to abort had significantly higher levels of IFNγ and IL-10 at day 35 post challenge and significantly higher levels of anti-chlamydial antibodies at 24 h post lambing compared to ewes that had live lambs.
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Affiliation(s)
- L M O'Neill
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Animal & Bioscience Department, Teagasc Grange, Dunsany, Co. Meath, Ireland.
| | - O M Keane
- Animal & Bioscience Department, Teagasc Grange, Dunsany, Co. Meath, Ireland
| | - P J Ross
- Department of Agriculture, Food and the Marine, Central Veterinary Research Laboratory, Backweston, Co. Kildare, Ireland
| | - J E Nally
- Infectious Bacterial Diseases, National Animal Disease Center, Agriculture Research Service, United States Department of Agriculture, Ames, IA, USA
| | - J Seshu
- South Texas Center for Emerging Infectious Diseases, Centre of Excellence in Infection Genomics and Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
| | - B Markey
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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9
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Effect of progesterone on the vaccination and immune response against Chlamydia abortus in sheep. Vet Immunol Immunopathol 2019; 213:109887. [PMID: 31307668 DOI: 10.1016/j.vetimm.2019.109887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/24/2018] [Accepted: 06/26/2019] [Indexed: 11/23/2022]
Abstract
Chlamydia abortus produces ovine enzootic abortion (OEA). Symptoms are not observed until the organism colonises the placenta, eventually causing abortion. Infected animals become carriers and will shed the organism in the following oestruses. This process suggests that sex hormones might play an important role in the physiopathology of OEA, affecting the success of chlamydial clearance and also jeopardising the effectiveness of vaccination. However, the mechanisms through which sex hormones are involved in chlamydial pathogenicity remain unclear. The aim of this study, therefore, was to determine the effect of progesterone on the immune response against C. abortus and on the protection conferred by an experimental inactivated vaccine in sheep. Eighteen sheep were ovariectomised and divided into four groups: vaccinated and progesterone-treated (V-PG), vaccinated and non-treated (V-NT), non-vaccinated and non-treated (NV-NT) and non-vaccinated and progesterone-treated sheep (NV-PG). Animals from both PG groups were treated with commercial medroxyprogesterone acetate impregnated intravaginal sponges before and during the vaccination (V-PG) or just before challenge (NV-PG). The animals from both V groups were subcutaneously immunised with an experimental inactivated vaccine, which was seen to confer high protection in previous studies. All sheep were challenged intratracheally with C. abortus strain AB7 and were sacrificed on day 8 post-infection. Morbidity was measured as the variation in rectal temperature and samples of sera were collected for antibody and cytokine (IFN-γ and IL-10) analysis by commercial ELISA. In addition, lung and lymph node samples were collected for chlamydial detection by qPCR and for histopathological and immunohistochemical analyses. Sheep from the V-PG group showed less severe or no lesions and lower morbidity than the other groups. They also had the highest abundance of regulatory T-cells. The sheep from V-NT also manifested high antibody levels against C. abortus and less severe lesions than those observed in non-vaccinated sheep, which showed high morbidity, low antibody levels and severe lesions, especially in NV-NT. These results confirm the effectiveness of the experimental vaccine employed and suggest that progesterone could enhance the effect.
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Antimicrobial Resistance in Chlamydiales, Rickettsia, Coxiella, and Other Intracellular Pathogens. Microbiol Spectr 2018; 6. [PMID: 29651977 DOI: 10.1128/microbiolspec.arba-0003-2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
This article will provide current insights into antimicrobial susceptibilities and resistance of an important group of bacterial pathogens that are not phylogenetically related but share lifestyle similarities in that they are generally considered to be obligate intracellular microbes. As such, there are shared challenges regarding methods for their detection and subsequent clinical management. Similarly, from the laboratory perspective, susceptibility testing is rarely undertaken, though molecular approaches might provide new insights. One should also bear in mind that the highly specialized microbial lifestyle restricts the opportunity for lateral gene transfer and, consequently, acquisition of resistance.
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11
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Cram ED, Rockey DD, Dolan BP. Chlamydia spp. development is differentially altered by treatment with the LpxC inhibitor LPC-011. BMC Microbiol 2017; 17:98. [PMID: 28438125 PMCID: PMC5402638 DOI: 10.1186/s12866-017-0992-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/28/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chlamydia species are obligate intracellular bacteria that infect a broad range of mammalian hosts. Members of related genera are pathogens of a variety of vertebrate and invertebrate species. Despite the diversity of Chlamydia, all species contain an outer membrane lipooligosaccharide (LOS) that is comprised of a genus-conserved, and genus-defining, trisaccharide 3-deoxy-D-manno-oct-2-ulosonic acid Kdo region. Recent studies with lipopolysaccharide inhibitors demonstrate that LOS is important for the C. trachomatis developmental cycle during RB- > EB differentiation. Here, we explore the effects of one of these inhibitors, LPC-011, on the developmental cycle of five chlamydial species. RESULTS Sensitivity to the drug varied in some of the species and was conserved between others. We observed that inhibition of LOS biosynthesis in some chlamydial species induced formation of aberrant reticulate bodies, while in other species, no change was observed to the reticulate body. However, loss of LOS production prevented completion of the chlamydial reproductive cycle in all species tested. In previous studies we found that C. trachomatis and C. caviae infection enhances MHC class I antigen presentation of a model self-peptide. We find that treatment with LPC-011 prevents enhanced host-peptide presentation induced by infection with all chlamydial-species tested. CONCLUSIONS The data demonstrate that LOS synthesis is necessary for production of infectious progeny and inhibition of LOS synthesis induces aberrancy in certain chlamydial species, which has important implications for the use of LOS synthesis inhibitors as potential antibiotics.
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Affiliation(s)
- Erik D Cram
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA.
| | - Daniel D Rockey
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
| | - Brian P Dolan
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
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12
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Wali S, Gupta R, Yu JJ, Lanka GKK, Chambers JP, Guentzel MN, Zhong G, Murthy AK, Arulanandam BP. Chlamydial protease-like activity factor mediated protection against C. trachomatis in guinea pigs. Immunol Cell Biol 2016; 95:454-460. [PMID: 27990018 PMCID: PMC5449249 DOI: 10.1038/icb.2016.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 01/30/2023]
Abstract
We have comprehensively demonstrated using the mouse model that intranasal immunization with recombinant chlamydial protease-like activity factor (rCPAF) leads to a significant reduction in bacterial burden, genital tract pathology and preserves fertility following intravaginal genital chlamydial challenge. In the present report, we evaluated the protective efficacy of rCPAF immunization in guinea pigs, a second animal model for genital chlamydial infection. Using a vaccination strategy similar to the mouse model, we intranasally immunized female guinea pigs with rCPAF plus CpG deoxynucleotides (CpG; as an adjuvant), and challenged intravaginally with C. trachomatis serovar D (CT-D). Immunization with rCPAF/CpG significantly reduced vaginal CT-D shedding and induced resolution of infection by day 24, compared to day 33 in CpG alone treated and challenged animals. Immunization induced robust anti-rCPAF serum IgG 2 weeks following the last immunization, and was sustained at a high level 4 weeks post challenge. Upregulation of antigen specific IFN-γ gene expression was observed in rCPAF/CpG vaccinated splenocytes. Importantly, a significant reduction in inflammation in the genital tissue in rCPAF/CpG-immunized guinea pigs compared to CpG-immunized animals was observed. Taken together, this study provides evidence of the protective efficacy of rCPAF as a vaccine candidate in a second animal model of genital chlamydial infection.
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Affiliation(s)
- Shradha Wali
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Rishein Gupta
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Gopala Krishna Koundinya Lanka
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - James P Chambers
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - M Neal Guentzel
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ashlesh K Murthy
- Department of Pathology, Midwestern University, Downers Grove, IL, USA
| | - Bernard P Arulanandam
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
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13
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Genital Chlamydia trachomatis: understanding the roles of innate and adaptive immunity in vaccine research. Clin Microbiol Rev 2016; 27:346-70. [PMID: 24696438 DOI: 10.1128/cmr.00105-13] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.
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14
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Corripio-Miyar Y, Hope J, McInnes CJ, Wattegedera SR, Jensen K, Pang Y, Entrican G, Glass EJ. Phenotypic and functional analysis of monocyte populations in cattle peripheral blood identifies a subset with high endocytic and allogeneic T-cell stimulatory capacity. Vet Res 2015; 46:112. [PMID: 26407849 PMCID: PMC4582714 DOI: 10.1186/s13567-015-0246-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/17/2015] [Indexed: 12/22/2022] Open
Abstract
Circulating monocytes in several mammalian species can be subdivided into functionally distinct subpopulations based on differential expression of surface molecules. We confirm that bovine monocytes express CD172a and MHC class II with two distinct populations of CD14+CD16low/-CD163+ and CD14−CD16++CD163low- cells, and a more diffuse population of CD14+CD16+CD163+ cells. In contrast, ovine monocytes consisted of only a major CD14+CD16+ subset and a very low percentage of CD14−CD16++cells. The bovine subsets expressed similar levels of CD80, CD40 and CD11c molecules and mRNA encoding CD115. However, further mRNA analyses revealed that the CD14−CD16++ monocytes were CX3CR1highCCR2low whereas the major CD14+ subset was CX3CR1lowCCR2high. The former were positive for CD1b and had lower levels of CD11b and CD86 than the CD14+ monocytes. The more diffuse CD14+CD16+ population generally expressed intermediate levels of these molecules. All three populations responded to stimulation with phenol-extracted lipopolysaccharide (LPS) by producing interleukin (IL)-1β, with the CD16++ subset expressing higher levels of IL-12 and lower levels of IL-10. The CD14−CD16++ cells were more endocytic and induced greater allogeneic T cell responses compared to the other monocyte populations. Taken together the data show both similarities and differences between the classical, intermediate and non-classical definitions of monocytes as described for other mammalian species, with additional potential subpopulations. Further functional analyses of these monocyte populations may help explain inter-animal and inter-species variations to infection, inflammation and vaccination in ruminant livestock.
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Affiliation(s)
- Yolanda Corripio-Miyar
- Division of Infection & Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Jayne Hope
- Division of Infection & Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Colin J McInnes
- Current address: Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK.
| | - Sean R Wattegedera
- Current address: Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK.
| | - Kirsty Jensen
- Division of Infection & Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Yvonne Pang
- Current address: Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK.
| | - Gary Entrican
- Division of Infection & Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK. .,Current address: Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK.
| | - Elizabeth J Glass
- Division of Infection & Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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15
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Álvarez D, Salinas J, Buendía AJ, Ortega N, del Río L, Sánchez J, Navarro JA, Gallego MC, Murcia-Belmonte A, Cuello F, Caro MR. Intratracheal infection as an efficient route for testing vaccines against Chlamydia abortus in sheep. Vet J 2015; 205:393-8. [PMID: 26095034 DOI: 10.1016/j.tvjl.2015.04.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/23/2015] [Accepted: 04/29/2015] [Indexed: 10/23/2022]
Abstract
Pregnant ewes have been widely used to test vaccines against Chlamydia abortus. However, this model entails many disadvantages such as high economic costs and long periods of pregnancy. The murine model is very useful for specific studies but cannot replace the natural host for the later stages of vaccine evaluation. Therefore, a non-pregnant model of the natural host might be useful for a vaccine trial to select the best vaccine candidates prior to use of the pregnant model. With this aim, two routes of infection were assessed in young non-pregnant sheep, namely, intranasal (IN) and intratracheal (IT). In addition, groups of non-vaccinated sheep and sheep immunised with an inactivated vaccine were established to investigate the suitability of the model for testing vaccines. After the experimental infection, isolation of the microorganism in several organs, with pathological and immunohistochemical analyses, antibody production assessment and investigation by PCR of the presence of chlamydia in the vagina or rectum were carried out. Experimental IT inoculation of C. abortus induced pneumonia in sheep during the first few days post-infection, confirming the suitability of the IT route for testing vaccines in the natural host. The course of infection and the resulting pathological signs were less severe in vaccinated sheep compared with non-vaccinated animals, demonstrating the success of vaccination. IN infection did not produce evident lesions or demonstrate the presence of chlamydial antigen in the lungs and cannot be considered an appropriate model for testing vaccines.
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Affiliation(s)
- D Álvarez
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - J Salinas
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - A J Buendía
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - N Ortega
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - L del Río
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - J Sánchez
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - J A Navarro
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - M C Gallego
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - A Murcia-Belmonte
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - F Cuello
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain
| | - M R Caro
- Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
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16
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Chlamydia abortus: New Aspects of Infectious Abortion in Sheep and Potential Risk for Pregnant Women. CURRENT CLINICAL MICROBIOLOGY REPORTS 2015. [DOI: 10.1007/s40588-015-0014-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Entrican G, Wattegedera SR, Griffiths DJ. Exploiting ovine immunology to improve the relevance of biomedical models. Mol Immunol 2014; 66:68-77. [PMID: 25263932 PMCID: PMC4368439 DOI: 10.1016/j.molimm.2014.09.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/19/2014] [Accepted: 09/01/2014] [Indexed: 12/29/2022]
Abstract
Sheep make a valuable contribution to immunology research. Lessons to be learned from studying infections in the natural host. Factors to consider when selecting biomedical models.
Animal models of human disease are important tools in many areas of biomedicine; for example, in infectious disease research and in the development of novel drugs and medical devices. Most studies involving animals use rodents, in particular congenic mice, due to the availability of a wide number of strains and the ease with which they can be genetically manipulated. The use of mouse models has led to major advances in many fields of research, in particular in immunology but despite these advances, no animal model can exactly reproduce all the features of human disease. It is increasingly becoming recognised that in many circumstances mice do not provide the best model and that alternative species may be more appropriate. Here, we describe the relative merits of sheep as biomedical models for human physiology and disease in comparison to mice, with a particular focus on reproductive and respiratory pathogens.
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Affiliation(s)
- Gary Entrican
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK.
| | - Sean R Wattegedera
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK
| | - David J Griffiths
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, Scotland, UK
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Evaluation of the relationship between Chlamydia pecorum sequence types and disease using a species-specific multi-locus sequence typing scheme (MLST). Vet Microbiol 2014; 174:214-22. [PMID: 25223647 DOI: 10.1016/j.vetmic.2014.08.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/28/2014] [Accepted: 08/14/2014] [Indexed: 11/22/2022]
Abstract
Chlamydia pecorum is globally associated with several ovine diseases including keratoconjunctivitis and polyarthritis. The exact relationship between the variety of C. pecorum strains reported and the diseases described in sheep remains unclear, challenging efforts to accurately diagnose and manage infected flocks. In the present study, we applied C. pecorum multi-locus sequence typing (MLST) to C. pecorum positive samples collected from sympatric flocks of Australian sheep presenting with conjunctivitis, conjunctivitis with polyarthritis, or polyarthritis only and with no clinical disease (NCD) in order to elucidate the exact relationships between the infecting strains and the range of diseases. Using Bayesian phylogenetic and cluster analyses on 62 C. pecorum positive ocular, vaginal and rectal swab samples from sheep presenting with a range of diseases and in a comparison to C. pecorum sequence types (STs) from other hosts, one ST (ST 23) was recognised as a globally distributed strain associated with ovine and bovine diseases such as polyarthritis and encephalomyelitis. A second ST (ST 69) presently only described in Australian animals, was detected in association with ovine as well as koala chlamydial infections. The majority of vaginal and rectal C. pecorum STs from animals with NCD and/or anatomical sites with no clinical signs of disease in diseased animals, clustered together in a separate group, by both analyses. Furthermore, 8/13 detected STs were novel. This study provides a platform for strain selection for further research into the pathogenic potential of C. pecorum in animals and highlights targets for potential strain-specific diagnostic test development.
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Longbottom D, Livingstone M, Maley S, van der Zon A, Rocchi M, Wilson K, Wheelhouse N, Dagleish M, Aitchison K, Wattegedera S, Nath M, Entrican G, Buxton D. Intranasal infection with Chlamydia abortus induces dose-dependent latency and abortion in sheep. PLoS One 2013; 8:e57950. [PMID: 23469113 PMCID: PMC3585262 DOI: 10.1371/journal.pone.0057950] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 01/27/2013] [Indexed: 02/07/2023] Open
Abstract
Background Latency is a key feature of the animal pathogen Chlamydia abortus, where infection remains inapparent in the non-pregnant animal and only becomes evident during a subsequent pregnancy. Often the first sign that an animal is infected is abortion occurring late in gestation. Despite this, little is understood of the underlying mechanisms that control latency or the recrudescence of infection that occurs during subsequent pregnancy. The aim of this study was to develop an experimental model of latency by mimicking the natural route of infection through the intranasal inoculation of non-pregnant sheep with C. abortus. Methodology/Principal Findings Three groups of sheep (groups 1, 2 and 3) were experimentally infected with different doses of C. abortus (5×103, 5×105 and 5×107 inclusion forming units (IFU), respectively) prior to mating and monitored over 2 breeding cycles for clinical, microbiological, pathological, immunological and serological outcomes. Two further groups received either negative control inoculum (group 4a,b) or were inoculated subcutaneously on day 70 of gestation with 2×106 IFU C. abortus (group 5). Animals in groups 1, 2 and 5 experienced an abortion rate of 50–67%, while only one animal aborted in group 3 and none in group 4a,b. Pathological, microbiological, immunological and serological analyses support the view that the maternal protective immune response is influenced by initial exposure to the bacterium. Conclusions/Significance The results show that intranasal administration of non-pregnant sheep with a low/medium dose of C. abortus results in a latent infection that leads in a subsequent pregnancy to infection of the placenta and abortion. In contrast a high dose stimulates protective immunity, resulting in a much lower abortion rate. This model will be useful in understanding the mechanisms of infection underlying latency and onset of disease, as well as in the development of novel therapeutics and vaccines for controlling infection.
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