Abstracts (complete list) - Wissenschaft Online

Sebastian Temme, Anna Maria Eis-Hübinger, Peter Kuckenberg
Targeting of the major histocompatibility complex class II
pathway by herpes simplex virus type-1 glycoprotein B
The HSV-1 encoded envelope protein gB mediates contact of the virus with the cell
surface and initiates fusion with the plasma membrane. We discovered that gB is
involved in an immune evasion strategy of HSV-1, targeting the MHC class II processing
pathway, presumably to prevent presentation of viral peptides. Recently, we co-isolated
complexes of HSV-1gB and MHC class II molecules from HSV-1 infected cells. In further
studies the intracellular encounter of gB and MHC class II and their subcellular
localisation was investigated. In transfected cells, invariant chain competes with gB for
binding to MHC II subunits within the ER and largely prevents association of gB to MHC
class II molecules. However, in the absence of invariant chain, gB and MHC class II
subunits form aggregates that are retained in the ER. Despite the large excess of
invariant chain, in gB-transfected cells some gB is found in association with MHC class
II. Furthermore, the MHC II/gB complexes were not dectected on the cell surface. We
conclude, that gB and MHC class II are transported separately and encounter after
dissociation of invariant chain from MHC class II heterodimers, probably in endosomal
compartments. Targeting of MHC II heterodimers by gB upon HSV-1 infection may
silence a CD4+ T cell response.