Maedi-visna virus infection of ovine mammary epithelial cells

Abstract

-The aim of this work was to perform a complete study of maedi-visna virus (MVV) infected mammary glands of naturally-infected sheep, and to determine if cells other than macrophages undergo a productive viral infection in this organ. Fifteen seropositive and two seronegative ewes were selected from MVV-infected flocks on the basis of clinical indurative mastitis and three sheep from an MVV-free flock. Within the mammary gland, MVV-positive cells were located by immunohistochemistry in the stroma and the epithelial alveolar barrier, most likely the ovine mammary epithelial cells (OMEC) of the acini. In situ hybridization confirmed these findings. Ultrastructural studies showed the presence of lentivirus-like particles budding off the cell surface in the alveolar barrier and also free in the acinar lumen. The presence of mammary histopathological lesions and MVV together with clear indications of productive infection (demonstration of a cytopathic effect in OMEC cultures and infection of co-cultures) were observed in the 15 seropositive and one of the seronegative sheep from the infected flock. These findings demonstrate that the OMEC were infected in vivo and probably underwent productive infection when studied ex-vivo. The OMEC of MVV-free sheep, which had subsequently been infected in vitro with MVV, also showed productive infection when challenged in vitro, confirming the replication of MVV in OMEC in vitro. The presence of MVV-infected OMEC in the mammary gland from infected animals, the productive infection in these OMEC and the release of lentiviral particles to the acinar lumen may have relevance in the pathogenesis and transmission of MVV infection. maedi-visna / mammary gland / epithelial cells / indurative mastitis / ovine

Ovine Progressive Pneumonia Virus Capsid Antigen as Found in CD163- and CD172a-Positive Alveolar Macrophages of Persistently Infected Sheep

“…The presence of OPPV CA in alveolar macrophages of the mammary gland is consistent with previous research where viral RNA and CA have been found in sheep mammary cells with the morphology of macrophages. 6,8,23,39 These combined results suggest that CD163-or CD172a-positive alveolar macrophages acquired OPPV CA by phagocytosis of CA, whole virus, or virusinfected cells and/or by receptor-mediated endocytosis of whole virus. HIV can infect cells using receptor-mediated endocytosis via dynamin; thus, OPPV could have a similar way of infecting alveolar macrophages.…”

Goat umbilical cord cells are permissive to small ruminant lentivirus infection in vitro

“…Other cell types permissive for small ruminant lentivirus infection are microglia 18 ; dendritic cells 2 ; epithelial cells from the lung 19 ; mammary gland 20 ; third eye lid 21 ; kidney 22 ; uterus and epididymis23, 24 and endothelium; smooth myocytes19, 25; granulosa cells 26 ; and parenchyma cells from the liver and heart 27 …”

Small Ruminant Lentiviruses and Human Immunodeficiency Virus: Cousins that Take a Long View

“…In severe cases, lymphoid follicles with or without germinal centres develop. Virus can be detected using in situ hybridization and PCR techniques in macrophages and in ductal epithelial cells, and isolated from epithelial cells from explanted mammary tissue [14,264]. The lesions are thus thought to be progressive.…”