Development and molecular studies on Equine Herpesvirus type 1 (EHV-1) vaccine against foot and mouth disease virus ; Entwicklung und molekulare Charakterisierung eines Equinen Herpesvirus Typ 1-basierten Impfstoffes gegen das Maul-und-Klauenseuche-Virus

Equine herpesvirus-1 is an alphaherpesvirus affecting equid species resulting in severe clinical outcomes manifested clinically as respiratory infection, abortion and nervous manifestations. EHV-1 establishes cell-associated viremia, following respiratory infection, reaching the target endothelial lining of blood vessel of reproductive tract and nervous system, resulting in vasculitis and thrombosis exhibited as clinical outcomes. Although PBMC-EC interface is very crucial in virus pathogenesis and clinical outcomes advent, the mechanisms underlying virus transfer from infected PBMC to EC are still unknown. To investigate these mechanisms, two-step en passant mutagenesis, functional assays (contact assays, transwell assays and flow chamber assay) together with confocal immunofluorescence data and laser scanning live cell imaging and electron microscope were executed. The single viral particle or viral cluster was found to colocalize with the extracellular matrix components. Viral particle or viral clusters embedding within these extracellular matrices are protected from the neutralizing antibodies and efficiently transmitted to endothelial cells. Destruction of this extracellular matrix from infected PBMC surface affects the infectious capability of PBMC. EHV-4, although found colocalized with ECM, is not transmitted from infected PBMC either in the static or dynamic conditions conjecturing their trapping and inactivation in these structures. Two genes, gB and gD have been implicated their role in virus transfer between PBMC and EC. Another two important mechanisms were assessed for the first time, membrane fusion between infected PBMC and endothelial cell as a mode of cell-to-cell transmission and the other one is the transcellular migration of PBMC into the endothelial cells transferring the virus to them. Two important events had been detected and caught by electron microscopy and require further and deep investigation. The first event is the first-time detection of microvesicle including equine herpesvirus-1 ...