Session topic


Title: Influence of glycoprotein O polymorphism of human cytomegalovirus on cell-cell spread
ID: PS 24
Type: Poster session
Talk time: 3 + 2 min
Session: Poster session 1
Receptors and entry

Speaker: Helene Hoenigsperger (Vienna/AT)

Abstract - Text

Abstract text (incl. references and figure legends)

Introduction: Human cytomegalovirus (HCMV) is one of the leading causes for severe disease in individuals with dysfunctional or immature immune system. HCMV enters the host cell using various glycoproteins on the viral envelope. Glycoprotein O (gO) forms a trimeric complex with glycoprotein H and glycoprotein L, which seems to be necessary for the cell-free infection of various cell types. However, in the human body, it is suggested, that viral transmission occurs by cell-cell spread, rather than cell-free spread.
Objectives: So far the role of gO during cell-cell spread and which effect its high polymorphism has on it, is largely unknown. Here we study cell-cell spread of different gO mutants in fibroblasts and epithelial cells.
Materials & Methods: gO recombinants of the 5 major genotypes, 2 chimeric and 2 cysteine mutants with TB40-BAC4-luc as background strain (gO GT1c) were used to evaluate cell-cell spread activity. Fibroblasts and epithelial cells were infected and incubated for 6 or 12 days. Infected cells and plaques were visualized by immunofluorescent staining of immediate early protein and counted with ImageJ.
Results: Initial screening analysis of all gO mutants suggested subtle differences whereas GT5 and the cysteine mutant GT4 C226S show a bigger plaque phenotype while the chimeric mutant GT1c/3 shows a smaller plaque phenotype compared to parental strain gO GT1c. These 3 gO mutants along with gO GT1c and strain Merlin, which harbors gO GT5 in an otherwise substantially different genome background, were further tested again for their cell-cell spread ability. Comparison of 3 independent experiments by one-way ANOVA with Dunnett´s multiple comparison test revealed no significant differences between the cell-cell spreading ability of gO mutants with TB40-BAC4 background strain, in fibroblasts and epithelial cells. Strain Merlin, in contrast, shows a severely different cell-cell spread phenotype.
Conclusion: Differences in cell-cell spread among HCMV strains seem to be independent of gO polymorphism.