title: Characterization of thymus atrophy in calves with subclinical BVD challenged with BHV-1.
abstract: Since the thymus is a target organ for the bovine viral diarrhea virus (BVDV), our experiment aimed to understand its relationship with the immunosuppressive effect by studying the consequences of a previous infection with BVDV on the thymus of calves challenged with bovine herpesvirus 1.1 (BHV-1). For this purpose, 12 animals were inoculated intranasally with non-cytopathic BVDV-1; 12 days later, 10 of them were coinfected intranasally with BHV-1. These animals were euthanized in batches of two at 0, 1, 2, 4, 7 or 14 dpi with BHV-1. Another 10 calves were inoculated solely with BHV-1 and euthanized in batches of two at 1, 2, 4, 7 or 14 dpi with BHV-1; two uninoculated calves were used as negative controls. Thymus samples from these animals were processed for viral detection and histopathological, immunohistochemical, and ultrastructural studies focused on BVDV/BHV-1 antigens, cortex:medulla ratio, apoptosis (TUNEL and caspase-3), collagen deposition, and factor VIII endothelial detection. Our study revealed the immunohistochemical presence of BVDV antigen in all animals in the BVDV-infected group, unlike BHV-1 detection, which was observed in animals in both infection groups only by molecular techniques. BVDV-preinfected animals showed severe atrophic changes associated with reduced cortex:medulla ratio, higher presence of cortical apoptosis, and increased collagen deposition and vascularization. However, calves solely infected with BHV-1 did not show atrophic changes. These findings could affect not only the numbers of circulating and local mature T cells but also the T cell-mediated immunity, which seems to be impaired during infections with this virus, thus favoring pathogenic effects during secondary infections.
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Agrifood Campus of International Excellence (ceiA3), 14014 Córdoba, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Romero-Palomo
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Agrifood Campus of International Excellence (ceiA3), 14014 Córdoba, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Risalde
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Agrifood Campus of International Excellence (ceiA3), 14014 Córdoba, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Molina
authors.affiliation: Department of Veterinary Science and Public Health, University of Milan, 20133 Milan, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Lauzi
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Agrifood Campus of International Excellence (ceiA3), 14014 Córdoba, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Bautista
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Agrifood Campus of International Excellence (ceiA3), 14014 Córdoba, Spain. Electronic address: jcgomez@uco.es.
authors.forename: J C
authors.initials: JC
authors.lastname: Gómez-Villamandos
mesh_terms: D000818:Animals; D001284:Atrophy; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000821:virology*; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology; D006566:Herpesviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D007242:Herpesvirus 1, Bovine; D020287:In Situ Nick-End Labeling; D013950:Thymus Gland / Q000473:pathology*
keywords: Apoptosis; Bovine herpesvirus type 1 (BHV-1); Bovine viral diarrhea virus (BVDV); Immunohistochemistry; Thymus atrophy