Adhesion and Mechanical Properties of RSV Infected Human Epithelial Cells

Respiratory syncytial virus is the leading cause of lower respiratory tract infection in infants and currently lacks an effective vaccine or treatment beyond symptom relief. The atomic force microscope is particularly well suited for imaging biological samples including cells, DNA, viruses and proteins. Analysis of fixed HEP-2 cells with the AFM after infection and incubation with RSV for periods of 0.5-24 h reveals several physical changes within the cells that may lead to a better understanding of the viral effects on living cells. Analysis of force-distance curves reveals changes in the mechanical properties of the cells throughout the infection period as well as changes in the surface chemistry, specifically in the presence of hydrophobic domains, of the cell membrane as shown by variability in the measured adhesion force. Elastic moduli of the fixed cells did not show a statistically significant trend, but hydrophobic molecular expression on the cellular surface decreased with increasing infection period. This change in the chemical nature of the cell membrane might be explained by the rapid removal, repair and replacement of the lipid bilayer occurring as a result of the exocytosis of RSV virions. (C) Koninklijke Brill NV, Leiden, 2011