Figure 5. Models for crawling and gliding movements of IAV particles on fetuin-coated surfaces.

(a) Immediately after a virus attaches to the fetuin-coated surface, multiple HA-receptor interactions tightly bind the virus to the surface. (b) Viral NA degrades receptors near the virus attachment site. The HA-receptor pairs thus decrease in number, and the virus becomes loosely attached to the cell surface. (c) Using iterative association and dissociation of HA-receptor interactions as a driving mechanism, the loosely attached virus performs crawling and gliding movements until reaching a site where multiple HA-receptor pairs can form and, again, tightly bind the virus to the surface.