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da Silveira BP, Cohen ND, Lawhon SD, Watson RO, Bordin AI. Protective immune response against Rhodococcus equi: An innate immunity-focused review. Equine Vet J 2024. [PMID: 39258739 DOI: 10.1111/evj.14214] [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: 02/27/2024] [Accepted: 07/30/2024] [Indexed: 09/12/2024]
Abstract
Rhodococcus equi causes pyogranulomatous pneumonia in foals and immunocompromised people. Despite decades of research efforts, no vaccine is available against this common cause of disease and death in foals. The purpose of this narrative review is to summarise the current understanding of interactions between R. equi and the host innate immune system, to describe features of the immune response that are associated with resistance or susceptibility to R. equi infection, and help guide strategies for developing novel approaches for preventing R. equi infections. Virulence of R. equi in foals has been attributed to the virulence associated protein A which allows intracellular survival in macrophages by preventing acidification of R. equi-containing vacuole. Additionally, foal susceptibility to R. equi infection is associated with immaturity and naivety of innate and adaptive immune systems, while adult horses with fully functional immune system are resistant to pneumonia. Specific interaction between R. equi and innate immune cells can result in bacterial survival or death; learning how to manipulate these responses to control infection is critical to prevent pneumonia in foals. Administration of live vaccines and stimulation of innate immune responses appears to improve foals' immune response and has the potential to overcome the challenges of foal active vaccination and elicit protection against pneumonia.
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Affiliation(s)
- Bibiana Petri da Silveira
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, Texas A&M University, School of Veterinary Medicine & Biomedical Sciences, College Station, Texas, USA
| | - Noah D Cohen
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, Texas A&M University, School of Veterinary Medicine & Biomedical Sciences, College Station, Texas, USA
| | - Sara D Lawhon
- Department of Veterinary Pathobiology, Texas A&M University, School of Veterinary Medicine & Biomedical Sciences, College Station, Texas, USA
| | - Robert O Watson
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, School of Medicine, College Station, Texas, USA
| | - Angela I Bordin
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, Texas A&M University, School of Veterinary Medicine & Biomedical Sciences, College Station, Texas, USA
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Higgins C, Huber L. Rhodococcus equi: challenges to treat infections and to mitigate antimicrobial resistance. J Equine Vet Sci 2023:104845. [PMID: 37295760 DOI: 10.1016/j.jevs.2023.104845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/01/2023] [Accepted: 06/03/2023] [Indexed: 06/12/2023]
Abstract
Rhodococcus equi, a gram-positive facultative intracellular pathogen and a soil saprophyte, is one of the most common causes of pneumonia in young foals. It poses a threat to the economy in endemic horse-breeding farms and to animal welfare annually. Many farms use thoracic ultrasonographic screening and antimicrobial treatment of subclinically affected foals as a preventive measure against severe R. equi infections. The wide use antimicrobials to treat subclinically affected foals has contributed to the emergence of multidrug resistant (MDR)-R. equi in both clinical isolates from sick foals and in the environment of horse-breeding farms. Alternatives to treat foals infected with MDR-R. equi are scarce and the impact of the emergence of MDR-R. equi in the environment of farms is still unknown. The aim of this review is to discuss the emergence of MDR-R. equi in the United States and the challenges faced to guide antimicrobial use practices. Reduction of antimicrobial use at horse-breeding farms is essential for the preservation of antimicrobial efficacy and, ultimately, human, animal, and environmental health.
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Affiliation(s)
- Courtney Higgins
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, 1130 Wire Road, Auburn, Alabama, USA 36832.
| | - Laura Huber
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, 1130 Wire Road, Auburn, Alabama, USA 36832.
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Bordin AI, Huber L, Sanz M, Cohen N. Rhodococcus equi Foal Pneumonia: Update on Epidemiology, Immunity, Treatment, and Prevention. Equine Vet J 2022; 54:481-494. [PMID: 35188690 DOI: 10.1111/evj.13567] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/03/2022] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
Pneumonia in foals caused by the bacterium Rhodococcus equi has a worldwide distribution and is a common cause of disease and death for foals. The purpose of this narrative review is to summarise recent developments pertaining to the epidemiology, immune responses, treatment, and prevention of rhodococcal pneumonia of foals. Screening tests have been used to implement earlier detection and treatment of foals with presumed subclinical R. equi pneumonia to reduce mortality and severity of disease. Unfortunately, this practice has been linked to the emergence of antimicrobial resistant R. equi in North America. Correlates of protective immunity for R. equi infections of foals remain elusive, but recent evidence indicates that innate immune responses are important both for mediating killing and orchestrating adaptive immune responses. A macrolide antimicrobial in combination with rifampin remains the recommended treatment for foals with R. equi pneumonia. Great need exists to identify which antimicrobial combination is most effective for treating foals with R. equi pneumonia and to limit emergence of antimicrobial-resistant strains. In the absence of an effective vaccine against R. equi, passive immunisation remains the only commercially-available method for effectively reducing the incidence of R. equi pneumonia. Because passive immunisation is expensive, labour-intensive, and carries risks for foals, great need exists to develop alternative approaches for passive and active immunisation.
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Affiliation(s)
- Angela I Bordin
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
| | - Laura Huber
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, 36849, USA
| | - Macarena Sanz
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, 99164-6610, USA
| | - Noah Cohen
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
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Aslam MW, Lau SF, Chin CSL, Ahmad NI, Rahman NA, Kuppusamy K, Omar S, Radzi R. Clinicopathological and radiographic features in 40 cats diagnosed with pulmonary and cutaneous Rhodococcus equi infection (2012-2018). J Feline Med Surg 2020; 22:774-790. [PMID: 32400257 PMCID: PMC7206563 DOI: 10.1177/1098612x19886395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVES This retrospective study aimed to describe clinical manifestations, diagnostic options, radiological features, therapeutic plans and outcomes for cats infected with Rhodococcus equi. METHODS Forty cats aged between 2 months and 11 years old (median 6 months) that were definitively diagnosed with rhodococcosis between 2012 and 2018 were recruited in this study. Medical records were reviewed for information on signalment, history, clinical presentation, diagnostic testing, treatment plans and clinical outcomes. RESULTS Of the 40 cats, 36 showed the pulmonary form of the disease, with 35 (87.5%) presenting with dyspnoea, while four cats presented with only cutaneous lesions. Mean body temperature was 38.7 ± 0.2°C. Dyspnoea was noted in 87.5% of the cats. Leukocytosis (58.3%) with band neutrophilia (83.3%), monocytosis (58.3%) and thrombocytopenia (55.5%) were prominent findings in the haematology reports. Hyperproteinaemia (61.1%) with hypoalbuminaemia (22.2%) and hyperglobulinaemia (63.8%) with a low albumin:globulin ratio (38.9%) were prominent features of blood biochemistry reports. An alveolar-interstitial pattern was noted in 75% of pre-thoracocentesis radiographs. Pleural effusion, hepatomegaly, thoracic lymphadenopathy and atelectasis of any lung lobe were seen in 88.9%, 75%, 41.7% and 36.1% of cats, respectively. Overall, the mortality rate was 67.5% in both forms. CONCLUSIONS AND RELEVANCE Clinicians should be aware that feline rhodococcosis manifests as a pulmonary disease at a much higher rate than previously reported. Further studies are required to address the epidemiology, pathophysiology, disease management and prognosis of feline rhodococcosis. The role of immunosuppression as a predisposing factor in feline rhodococcosis requires further investigation.
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Affiliation(s)
- Muhammad Waseem Aslam
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Seng Fong Lau
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Chelly Sze Lee Chin
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Nur Indah Ahmad
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Nor-Alimah Rahman
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Krishnammah Kuppusamy
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Sharina Omar
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
| | - Rozanaliza Radzi
- Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia
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Transcriptome analysis of immune genes in peripheral blood mononuclear cells of young foals and adult horses. PLoS One 2018; 13:e0202646. [PMID: 30183726 PMCID: PMC6124769 DOI: 10.1371/journal.pone.0202646] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 08/07/2018] [Indexed: 12/14/2022] Open
Abstract
During the neonatal period, the ability to generate immune effector and memory responses to vaccines or pathogens is often questioned. This study was undertaken to obtain a global view of the natural differences in the expression of immune genes early in life. Our hypothesis was that transcriptome analyses of peripheral blood mononuclear cells (PBMCs) of foals (on day 1 and day 42 after birth) and adult horses would show differential gene expression profiles that characterize natural immune processes. Gene ontology enrichment analysis provided assessment of biological processes affected by age, and a list of 897 genes with ≥2 fold higher (p<0.01) expression in day 42 when compared to day 1 foal samples. Up-regulated genes included B cell and T cell receptor diversity genes; DNA replication enzymes; natural killer cell receptors; granzyme B and perforin; complement receptors; immunomodulatory receptors; cell adhesion molecules; and cytokines/chemokines and their receptors. The list of 1,383 genes that had higher (p<0.01) expression on day 1 when compared to day 42 foal samples was populated by genes with roles in innate immunity such as antimicrobial proteins; pathogen recognition receptors; cytokines/chemokines and their receptors; cell adhesion molecules; co-stimulatory molecules; and T cell receptor delta chain. Within the 742 genes with increased expression between day 42 foal and adult samples, B cell immunity was the main biological process (p = 2.4E-04). Novel data on markedly low (p<0.0001) TLR3 gene expression, and high (p≤0.01) expression of IL27, IL13RA1, IREM-1, SIRL-1, and SIRPα on day 1 compared to day 42 foal samples point out potential mechanisms of increased susceptibility to pathogens in early life. The results portray a progression from innate immune gene expression predominance early in life to adaptive immune gene expression increasing with age with a putative overlay of immune suppressing genes in the neonatal phase. These results provide insight to the unique attributes of the equine neonatal and young immune system, and offer many avenues of future investigation.
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Wang Y, Mao Q, Chang H, Wu Y, Pan S, Li Y, Zhang Y. Inability of FMDV replication in equine kidney epithelial cells is independent of integrin αvβ3 and αvβ6. Virology 2016; 492:251-8. [PMID: 27011223 DOI: 10.1016/j.virol.2016.01.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 01/24/2016] [Accepted: 01/29/2016] [Indexed: 10/22/2022]
Abstract
Integrins can function as receptors for foot-and-mouth disease virus (FMDV) in epithelium. Horses are believed to be insusceptible to this disease, but the mechanism of resistance remains unclear. To detect whether FMDV can use integrin to attach to equine epithelial, we compared the utilities of αvβ3 and αvβ6 between bovine and equine kidney epithelial cells (KECs). Equine KECs showed almost equal efficiency to those of bovine. Further, the integrin αv, β3, and β6 subunits from bovine and equine were cloned and vectors were transfected into SW480 cells and COS-1 cells alone or together, and virus titers were used to determine the viral replication. In all cases, the virus reproduced successfully. Overall, FMDV can replicate in SW480 cells transfected with equine β3/β6 subunits and COS-1 cells transfected with equine αvβ3/αvβ6 integrins, but not in EKECs. These results indicated that failure of FMDV replication in EKECs was not attributed to integrin receptors.
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Affiliation(s)
- Yanqin Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Qingfu Mao
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Huiyun Chang
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 Gansu, PR China
| | - Yongyan Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Shaohui Pan
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Yanhe Li
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China
| | - Yong Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Key Laboratory of Animal Biotechnology, Ministry of Agriculture, Northwest A&F University, Yangling 712100, Shaanxi, PR China.
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Composition and Diversity of the Fecal Microbiome and Inferred Fecal Metagenome Does Not Predict Subsequent Pneumonia Caused by Rhodococcus equi in Foals. PLoS One 2015; 10:e0136586. [PMID: 26305682 PMCID: PMC4549325 DOI: 10.1371/journal.pone.0136586] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/05/2015] [Indexed: 02/01/2023] Open
Abstract
In equids, susceptibility to disease caused by Rhodococcus equi occurs almost exclusively in foals. This distribution might be attributable to the age-dependent maturation of immunity following birth undergone by mammalian neonates that renders them especially susceptible to infectious diseases. Expansion and diversification of the neonatal microbiome contribute to development of immunity in the gut. Moreover, diminished diversity of the gastrointestinal microbiome has been associated with risk of infections and immune dysregulation. We thus hypothesized that varying composition or reduced diversity of the intestinal microbiome of neonatal foals would contribute to increased susceptibility of their developing R. equi pneumonia. The composition and diversity indices of the fecal microbiota at 3 and 5 weeks of age were compared among 3 groups of foals: 1) foals that subsequently developed R. equi pneumonia after sampling; 2) foals that subsequently developed ultrasonographic evidence of pulmonary abscess formation or consolidation but not clinical signs (subclinical group); and, 3) foals that developed neither clinical signs nor ultrasonographic evidence of pulmonary abscess formation or consolidation. No significant differences were found among groups at either sampling time, indicating absence of evidence of an influence of composition or diversity of the fecal microbiome, or predicted fecal metagenome, on susceptibility to subsequent R. equi pneumonia. A marked and significant difference identified between a relatively short interval of time appeared to reflect ongoing adaptation to transition from a milk diet to a diet including available forage (including hay) and access to concentrate fed to the mare.
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Hamza E, Mirkovitch J, Steinbach F, Marti E. Regulatory T cells in early life: comparative study of CD4+CD25high T cells from foals and adult horses. PLoS One 2015; 10:e0120661. [PMID: 25790481 PMCID: PMC4366079 DOI: 10.1371/journal.pone.0120661] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/25/2015] [Indexed: 11/28/2022] Open
Abstract
The immune system of mammals is subject to continuous development during the postnatal phase of life. Studies following the longitudinal development of the immune system in healthy children are limited both by ethical considerations and sample volumes. Horses represent a particular valuable large animal model for T regulatory (Treg) cells and allergy research. We have recently characterised Treg cells from horses, demonstrated their regulatory capability and showed both their expansion and induction in vitro. Insect bite hypersensitivity (IBH) is a common allergy in horses resembling atopic dermatitis and studies have shown that first exposure to allergens in adult life results in an increased incidence of IBH. The aim of the present study was to characterize circulating CD4+CD25highFoxP3+cells in foals, evaluate their suppressive capability and their in vitro induction compared to adult horses. 19 foals (age range, 1–5 months), their adult mothers and six one-year-old horses (yearlings) were included in the study. The proportion of FoxP3+ cells within the circulating CD4+CD25high population was significantly higher in foals (47%) compared to their mothers (18%) and to yearlings (26%). Treg cells from foals also displayed a higher suppressive capability. Furthermore, CD4+CD25high cells in foals could be induced in vitro from CD4+CD25− cells in a significantly higher proportion compared to mares. These cells also displayed a significantly enhanced suppressive capability. In summary these findings support the notion that exposure of horses to allergens during maturation of the immune system assists the establishment of induced (i)Treg driven tolerance.
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Affiliation(s)
- Eman Hamza
- Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- * E-mail:
| | - Jelena Mirkovitch
- Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Falko Steinbach
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Eliane Marti
- Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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The equine immune responses to infectious and allergic disease: a model for humans? Mol Immunol 2014; 66:89-96. [PMID: 25457878 DOI: 10.1016/j.molimm.2014.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/23/2014] [Accepted: 09/29/2014] [Indexed: 01/01/2023]
Abstract
The modern horse, Equus caballus has historically made important contributions to the field of immunology, dating back to Emil von Behring's description of curative antibodies in equine serum over a century ago. While the horse continues to play an important role in human serotherapy, the mouse has replaced the horse as the predominant experimental animal in immunology research. Nevertheless, continuing efforts have led to an improved understanding of the equine immune response in a variety of infectious and non-infectious diseases. Based on this information, we can begin to identify specific situations where the horse may provide a unique immunological model for certain human diseases.
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Berghaus LJ, Giguère S, Sturgill TL. Effects of age and macrophage lineage on intracellular survival and cytokine induction after infection with Rhodococcus equi. Vet Immunol Immunopathol 2014; 160:41-50. [PMID: 24736188 DOI: 10.1016/j.vetimm.2014.03.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 02/20/2014] [Accepted: 03/23/2014] [Indexed: 11/25/2022]
Abstract
Rhodococcus equi, a facultative intracellular pathogen of macrophages, causes life-threatening pneumonia in foals and in people with underlying immune deficiencies. As a basis for this study, we hypothesized that macrophage lineage and age would affect intracellular survival of R. equi and cytokine induction after infection. Monocyte-derived and bronchoalveolar macrophages from 10 adult horses and from 10 foals (sampled at 1-3 days, 2 weeks, 1 month, 3 months, and 5 months of age) were infected ex vivo with virulent R. equi. Intracellular R. equi were quantified and mRNA expression of IL-1β, IL-4, IL-6, IL-8, IL-10, IL-12 p40, IL-18, IFN-γ, and TNF-α was measured. Intracellular replication of R. equi was significantly (P<0.001) greater in bronchoalveolar than in monocyte-derived macrophages, regardless of age. Regardless of the macrophage lineage, replication of R. equi was significantly (P=0.002) higher in 3-month-old foals than in 3-day old foals, 2-week-old foals, 1-month-old foals, and adult horses. Expression of IL-4 mRNA was significantly higher in monocyte-derived macrophages whereas expression of IL-6, IL-18, and TNF-α was significantly higher in bronchoalveolar macrophages. Induction of IL-1β, IL-10, IL-12 p40, and IL-8 mRNA in bronchoalveolar macrophages of 1-3-day old foals was significantly higher than in older foals or adult horses. Preferential intracellular survival of R. equi in bronchoalveolar macrophages of juvenile horses may play a role in the pulmonary tropism of the pathogen and in the window of age susceptibility to infection.
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Affiliation(s)
- Londa J Berghaus
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States
| | - Steeve Giguère
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States.
| | - Tracy L Sturgill
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States
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