Current understanding of the equine immune response to Rhodococcus equi. An immunological review of R. equi pneumonia.
Abstract: Rhodococcus equi is recognised to cause chronic purulent bronchopneumonia in foals of less than 6 months of age. Virulent strains of the bacteria possess a large 80-90 kb plasmid encoding several virulence-associated proteins, including virulence-associated protein A (VapA), which is associated with disease. R. equi pneumonia can represent significant costs and wastage to the equine breeding industry, especially on stud farms where the disease is endemic. This article reviews knowledge of the equine immune response, both in the immune adult and susceptible neonate, with respect to this pathogen. Humoral immune responses are addressed, with a discussion on the use of hyperimmune and normal adult equine plasma as prophylactic tools. The role that innate immune mechanisms play in the susceptibility of some foals to R. equi infection is also highlighted. Likewise, cell-mediated immune components are reviewed, with particular attention directed towards research undertaken to develop an effective vaccine for foals. It is possible that the implementation of a single immunoprophylaxis strategy to prevent R. equi infection on farms will yield disappointing results. Combined prophylactic protocols that address husbandry practices, environmental and aerosol contamination levels, enhancement of innate immunity, good quality hyperimmune plasma for the neonate, and vaccinal efficacy in the developing foal may be required.
Copyright 2009 Elsevier B.V. All rights reserved.
Publication Date: 2009-12-23 PubMed ID: 20064668DOI: 10.1016/j.vetimm.2009.12.004Google Scholar: Lookup
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Summary
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This study explores the immune response of horses, both adult and neonate, to a bacterium called Rhodococcus equi, which causes severe pneumonia in foals and has significant financial implications for the horse breeding industry. The research addresses the potential prophylactic measures against this infection, such as hyperimmune plasma and vaccines, alongside improved husbandry practices and environmental controls.
About Rhodococcus equi
- Rhodococcus equi is a bacterium known to cause chronic purulent bronchopneumonia in young foals.
- The bacteria’s virulence, or disease-causing power, largely comes from a large 80-90 kb plasmid that it possesses. This plasmid encodes several virulence-associated proteins, with a key one being virulence-associated protein A (VapA).
- The disease can represent a substantial financial burden to the equine breeding industry, particularly on stud farms where it is common.
Equine Immune Response to R. equi
- The article reviews the immune response of horses, both adults and neonates, to this bacterial pathogen.
- It gives detailed attention to humoral immune responses and discusses the use of hyperimmune and normal adult equine plasma as therapeutic tools in the battle against R. equi.
- The paper also underscores the role of innate immunity in determining the susceptibility of some foals to R. equi infection.
Cell-Mediated Immune Components
- In addition to innate and humoral immunity, cell-mediated immune components are equally important in the equine response to R. equi infection.
- The article reviews a significant amount of research conducted to develop an effective vaccine for foals against R. equi.
Prophylactic Protocols
- The authors suggest that banking on a single preventive strategy to ward off R. equi infection might not achieve satisfactory results.
- They propose a combined preventive approach encompassing improved husbandry practices, control of environmental and aerosol contamination levels, enhancement of innate immunity, usage of hyperimmune plasma in newborns, and improving the efficacy of vaccines in developing foals.
Cite This Article
APA
Dawson TRMY, Horohov DW, Meijer WG, Muscatello G.
(2009).
Current understanding of the equine immune response to Rhodococcus equi. An immunological review of R. equi pneumonia.
Vet Immunol Immunopathol, 135(1-2), 1-11.
https://doi.org/10.1016/j.vetimm.2009.12.004 Publication
Researcher Affiliations
- The Faculty of Applied Sciences, University of Sunderland, Fleming Building, Wharncliffe Street, Sunderland SR1 3SD, UK. Electronic address: hc4tda@student.sunderland.ac.uk.
- Department of Veterinary Science, University of Kentucky, UK.
- School of Biomolecular and Biomedical Science, University College Dublin, Ireland.
- Faculty of Veterinary Science, The University of Sydney, Australia.
MeSH Terms
- Actinomycetales Infections / immunology
- Actinomycetales Infections / prevention & control
- Actinomycetales Infections / veterinary
- Animals
- Animals, Newborn / immunology
- Animals, Newborn / microbiology
- Bacterial Vaccines / immunology
- Horse Diseases / immunology
- Horse Diseases / microbiology
- Horse Diseases / prevention & control
- Horses / immunology
- Immunity, Humoral / immunology
- Immunity, Innate / immunology
- Pneumonia, Bacterial / immunology
- Pneumonia, Bacterial / veterinary
- Rhodococcus equi / immunology
Citations
This article has been cited 13 times.- Rakowska A, Marciniak-Karcz A, Bereznowski A, Cywińska A, Żychska M, Witkowski L. Less Typical Courses of Rhodococcus equi Infections in Foals.. Vet Sci 2022 Oct 31;9(11).
- Harvey AB, Bordin AI, Rocha JN, Bray JM, Cohen ND. Opsonization but not pretreatment of equine macrophages with hyperimmune plasma nonspecifically enhances phagocytosis and intracellular killing of Rhodococcus equi.. J Vet Intern Med 2021 Jan;35(1):590-596.
- Álvarez-Narváez S, Giguère S, Anastasi E, Hearn J, Scortti M, Vázquez-Boland JA. Clonal Confinement of a Highly Mobile Resistance Element Driven by Combination Therapy in Rhodococcus equi.. mBio 2019 Oct 15;10(5).
- Ramsay JD, Evanoff R, Mealey RH. Hepacivirus A Infection in Horses Defines Distinct Envelope Hypervariable Regions and Elucidates Potential Roles of Viral Strain and Adaptive Immune Status in Determining Envelope Diversity and Infection Outcome.. J Virol 2018 Sep 15;92(18).
- Gundelly P, Suzuki Y, Ribes JA, Thornton A. Differences in Rhodococcus equi Infections Based on Immune Status and Antibiotic Susceptibility of Clinical Isolates in a Case Series of 12 Patients and Cases in the Literature.. Biomed Res Int 2016;2016:2737295.
- Giles C, Ndi O, Barton MD, Vanniasinkam T. An Adenoviral Vector Based Vaccine for Rhodococcus equi.. PLoS One 2016;11(3):e0152149.
- Shaw SD, Cohen ND, Chaffin MK, Blodgett GP, Syndergaard M, Hurych D. Estimating the Sensitivity and Specificity of Real-Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals.. J Vet Intern Med 2015 Nov-Dec;29(6):1712-7.
- Okoko T, Blagova EV, Whittingham JL, Dover LG, Wilkinson AJ. Structural characterisation of the virulence-associated protein VapG from the horse pathogen Rhodococcus equi.. Vet Microbiol 2015 Aug 31;179(1-2):42-52.
- Erganis O, Sayin Z, Hadimli HH, Sakmanoglu A, Pinarkara Y, Ozdemir O, Maden M. The effectiveness of anti-R. equi hyperimmune plasma against R. equi challenge in thoroughbred Arabian foals of mares vaccinated with R. equi vaccine.. ScientificWorldJournal 2014;2014:480732.
- McQueen CM, Doan R, Dindot SV, Bourquin JR, Zlatev ZZ, Chaffin MK, Blodgett GP, Ivanov I, Cohen ND. Identification of genomic loci associated with Rhodococcus equi susceptibility in foals.. PLoS One 2014;9(6):e98710.
- Lohmann KL, Lopez AM, Manning ST, Marques FJ, Brownlie R, Allen AL, Sangster AE, Mutwiri G, Gerdts V, Potter A, Townsend HG. Failure of a VapA/CpG oligodeoxynucleotide vaccine to protect foals against experimental Rhocococcus equi pneumonia despite induction of VapA-specific antibody and interferon-γ response.. Can J Vet Res 2013 Jul;77(3):161-9.
- Bordin AI, Suchodolski JS, Markel ME, Weaver KB, Steiner JM, Dowd SE, Pillai S, Cohen ND. Effects of administration of live or inactivated virulent Rhodococccus equi and age on the fecal microbiome of neonatal foals.. PLoS One 2013;8(6):e66640.
- van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L. The steroid catabolic pathway of the intracellular pathogen Rhodococcus equi is important for pathogenesis and a target for vaccine development.. PLoS Pathog 2011 Aug;7(8):e1002181.
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