Fig 9. Models for cell-to-cell spread of HMPV in BEAS-2B cells.

Virus particles exit an infected cell and move inside an open-ended intercellular extension to infect a target cell (model 1). In model 2, virus particles move from an infected cell to a target cell at the surface of an intercellular extension. Replication bodies can be transmitted from an infected cell to a target cell along an intercellular extension (model 3).