title: Patterns of lesion and local host cellular immune response in natural cases of ovine maedi-visna.
abstract: This study investigates the nervous form of ovine maedi-visna by histological and immunohistochemical techniques. The aim was to study the lesion types and the local cellular immune response related to each lesion type, and the possible relationship between these parameters. Thirty-four Assaf ewes were studied, 29 of which had shown nervous signs. Microscopical lesion patterns were described according to location, extent and predominance of inflammatory cell type. Immunohistochemical labelling of T cells (CD3(+), CD4(+), CD8(+) and cells expressing the γδ form of the T-cell receptor), B cells and macrophages revealed clear differences between the lesion patterns. Two main lesion types were described. Lymphocytic lesions had areas of mild-moderate injury characterized by a predominance of infiltrating T cells. Histiocytic lesions were more severe and had extensive areas of malacia and dominant infiltration by macrophages and B cells. Each animal had a unique lesion pattern and these differences could be due to individual resistance to the progression of infection. The lymphocytic lesions appear to represent initial or latent phases of slow progression, in which the animal presents some natural resistance to the infection. The histiocytic pattern may reflect a poor immune response or a greater virulence of the viral strain.
authors: Section of Pathological Anatomy, Department of Animal Health, Veterinary School, University of León, 24007 León, Spain. lpolr@unileon.es
authors: L
authors: L
authors: Polledo
authors: J
authors: J
authors: González
authors: J
authors: J
authors: Benavides
authors: S
authors: S
authors: Morales
authors: B
authors: B
authors: Martínez-Fernández
authors: L
authors: L
authors: Delgado
authors: R
authors: R
authors: Reina
authors: I
authors: I
authors: Glaria
authors: V
authors: V
authors: Pérez
authors: M C
authors: MC
authors: Ferreras
authors: J F
authors: JF
authors: García Marín
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002490:Central Nervous System / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002831:Choroid Plexus / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006644:Histiocytes / Q000378:metabolism / Q000473:pathology; D054884:Host-Pathogen Interactions; D007111:Immunity, Cellular / Q000276:immunology*; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008578:Meninges / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D011021:Pneumonia, Progressive Interstitial, of Sheep / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D012756:Sheep; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D014790:Visna-maedi virus / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D016692:Receptors, Antigen, T-Cell, gamma-delta