362회 Targeting HSV-1 Heparan Sulphate-Dependent Cellular Entry Using S…

362회

연사 :  권 희 충, 원자력의학원 방사선의학연구센터

제목: Targeting HSV-1 Heparan Sulphate-Dependent Cellular Entry Using Soluble HveC153

Abstract

 HSV-1 initially attaches to cells through the binding of glycoproteins C and B (gC and gB) to glycosaminoglycans (GAGs) such as heparan sulphate (HS) moieties. Subsequent entry requires interaction between gD and one of the cell surface receptors, HveA or HveC. Virus-cell fusion requires the presence of gD, gB, gH/gL in the virion, but details of the process are not fully understood. Here we show that purified soluble HveC153, which is not bound to the cell surface, can activate viral entry by binding to virion gD. CHO-K1 cells do not express HveA or HveC and are normally resistant to HSV infection. A KOS-derived virus expressing a reporter gene was able to enter CHO-K1 cells efficiently (maximum 75% cells transduced) in the presence of soluble HveC153 in a dose- and MOI-dependent manner. Anti-gD antibodies specifically blocked this effect. Soluble HveC-mediated entry of HSV-1 into CHO-K cells depends on a binding event between gB/gC and cell surface GAGs. No viral entry was observed into CHO-K1 cells in the presence of a molar excess of haparan, or into CHO-pgsA745 cells that do not express GAGs. Furthermore, entry was abolished by simultaneous deletion of both gC and the HS binding domain of gB. These data support a model in which the HveC-gD interaction is a critical entry signal that triggers a downstream virion fusion cascade. As it is unnecessary for HveC to be attached to the cell surface, it seems likely that the fusion process occurs through interactions between virion glycoproteins and cell surface components other than gD and HveC. This observation leads us to hypothesise that it may be possible to re-direct the tropism of HSV-1 by substituting the attachment domains of gC or gB with ligands for specific cellular receptors, initiating the entry of virus into targeted cells by using soluble HveC153 as a viral fusogenic trigger, independent of the requirement for HveC on the cell surface.