Gene signatures associated with foot-and-mouth disease virus infection and persistence. Part I: Model of Persistent FMDV infection in a three-dimensional model of the bovine soft palate
Résumé
Foot-and-mouth disease virus (FMDV) is the etiologic agent of one of the most devastating diseases that affect cloven-hoofed livestock. Following acute infection, FMDV persists in the oropharynx, in particular in the soft palate, of a large proportion of cattle. The mechanisms that trigger this persistence remain unknown. The aim of this study was to characterise gene signatures within FMDV and its host, to identify factors that can be used to prevent or diagnose persistent infection. As a first step, an air-liquid interface multilayer model of soft palate (SP) cells from cattle was developed and was characterised by immunostaining and electron microscopy. After five weeks of culture without passage, approximately 20% of cells had still a polygonal morphology and displayed tight junctions, such as observed in stratified squamous epithelia. Cells with similar morphology expressed cytokeratin. The cells were then infected at an MOI of 0.01 or 1 with FMDV O/FRA/1/2001 and the infection was monitored by isolation in cell culture, qPCR, immunofluorescence and immunohistochemistry, until day 28. A limited cytopathic effect was induced, restricted to the upper cell layers. FMDV antigen, FMDV RNA and live FMDV were detected through day 1 to 28, with peaks at day 1 and 2. At day 28, FMDV antigen could still be detected in sparse cells. Combined with omics-technology, this new in vitro model opens unique possibilities to investigate the mechanisms of persistence of FMDV.