title: Oral Administration of Electron-Beam Inactivated Rhodococcus equi Failed to Protect Foals against Intrabronchial Infection with Live, Virulent R. equi.
abstract: There is currently no licensed vaccine that protects foals against Rhodococcus equi-induced pneumonia. Oral administration of live, virulent R. equi to neonatal foals has been demonstrated to protect against subsequent intrabronchial challenge with virulent R. equi. Electron beam (eBeam)-inactivated R. equi are structurally intact and have been demonstrated to be immunogenic when administered orally to neonatal foals. Thus, we investigated whether eBeam inactivated R. equi could protect foals against developing pneumonia after experimental infection with live, virulent R. equi. Foals (n = 8) were vaccinated by gavaging with eBeam-inactivated R. equi at ages 2, 7, and 14 days, or gavaged with equal volume of saline solution (n = 4), and subsequently infected intrabronchially with live, virulent R. equi at age 21 days. The proportion of vaccinated foals that developed pneumonia following challenge was similar among the vaccinated (7/8; 88%) and unvaccinated foals (3/4; 75%). This vaccination regimen did not appear to be strongly immunogenic in foals. Alternative dosing regimens or routes of administration need further investigation and may prove to be immunogenic and protective.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, United States of America.
authors.forename: Joana N
authors.initials: JN
authors.lastname: Rocha
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, United States of America.
authors.forename: Noah D
authors.initials: ND
authors.lastname: Cohen
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, United States of America.
authors.forename: Angela I
authors.initials: AI
authors.lastname: Bordin
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, United States of America.
authors.forename: Courtney N
authors.initials: CN
authors.lastname: Brake
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia, 30602-7385, United States of America.
authors.forename: Steeve
authors.initials: S
authors.lastname: Giguère
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, United States of America.
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Coleman
authors.affiliation: Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, 77843, United States of America.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Alaniz
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4467, United States of America.
authors.forename: Sara D
authors.initials: SD
authors.lastname: Lawhon
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4467, United States of America.
authors.forename: Waithaka
authors.initials: W
authors.lastname: Mwangi
authors.affiliation: National Center for Electron Beam Research-IAEA Collaborative Centre for Electron Beam Technology, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Suresh D
authors.initials: SD
authors.lastname: Pillai
mesh_terms: D000193:Actinomycetales Infections / Q000000981:diagnostic imaging / Q000662:veterinary*; D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D001980:Bronchi / Q000382:microbiology*; D004583:Electrons; D006734:Horse Diseases / Q000000981:diagnostic imaging / Q000276:immunology*; D006736:Horses; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000378:metabolism; D007371:Interferon-gamma / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D009666:Nose / Q000276:immunology; D016929:Rhodococcus equi / Q000502:physiology*; D016896:Treatment Outcome; D014463:Ultrasonography; D014611:Vaccination / Q000662:veterinary; D014774:Virulence
chemical_list: D007074:Immunoglobulin G; D007371:Interferon-gamma
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