Doctor of Philosophy
Department of Biology
Shahgasempour, Shapour, Changes in endothelial cell integrin and cell adhesion receptors caused by human cytomegalovirus, Doctor of Philosophy thesis, Department of Biology, University of Wollongong, 1994. http://ro.uow.edu.au/theses/1065
The interaction of human cytomegalovirus (HCMV) with human endothelial cells was studied using the laboratory adapted strain (AD 169) and a recent clinical isolate (clin-HCMV) which was propagated in endothelial cells. Endothelial cells were isolated from human umbilical vein cord (HUVEC) and challenged with HCMV for time periods of 6, 12, 18 and 24 hours. By 6 hours post challenge, HUVEC challenged with clin- HCMV exhibited defective adhesion to fibronectin, collagen type IV and laminin components of extracellular matrix proteins, but not to collagen type I. Flow cytometric analysis demonstrated that clin-HCMV challenged endothelial cells expressed decreased levels of integrins 0:5(31 (a fibronectin receptor) and oc2pi (a collagen and laminin receptor) and slightly concomitant increased cell surface expression of a3fil (a collagen, laminin, and fibronectin receptor) and a6^1 (a laminin receptor). It is proposed that the decreased adherence of endothelial cells to the components of extracellular matrix proteins used in this study are, in part, due to decreased cell surface expression of a5fil and oc2pi integrin receptors and is caused by an immediate-early and/or early function(s) of clin-HCMV.
In addition virus challenged endothelial cells showed increased adhesiveness for polymorphonuclear cells (PMN), monocytes and T- lymphocytes. The effect of clin-HCMV on the expression of endothelial cell adhesion molecules ELAM-1, ICAM-1, ICAM-2, VCAM-1 and HLA classI was studied. It was found that clin-HCMV challenge induced the increased cell surface expression of ELAM-1 at 18 hours post challenge, providing a mechanism for the augmented adherence of polymorphonuclear cells and T-lymphocytes. The clin-HCMV was also found to increase the cell surface expression of ICAM-1 and VCAM-1 as early as 6 hours post infection with cell surface expression increasing with increasing times post challenge, while the levels of ICAM-2 remained unchanged as compared to mock challenged cells. Attachment inhibition studies revealed that these adhesion molecules were involved in the increased adhesiveness of endothelial cells for PMN , T-lymphocytes and monocytes. Further, clin-HCMV challenged endothelial cells expressed reduced levels of HLA class I by 6 hours post infection with the cell surface expression increasing by 18 hours post challenged. It is proposed that the early changes seen in these marker expression are due to an immediate-early and/or early function(s) of HCMV.
These results suggest that HCMV, particularly a recent clinical isolate, propagated in endothelial cells, is capable of inducing functional changes in endothelial cells. The altered expression of cell-matrix and cell-cell adhesion molecules resulting from HCM V challenge could contribute to the immunopathology associated with HCM V infection in vivo.