FIG 3.

Intercellular connections formed during IAV infection require actin dynamics and F-actin but do not require microtubules and occur more frequently during infection. (A) MDCK cells were infected with IAV at an MOI of 3. At 1 h p.i., 30 μM IPA-3, 100 μM paclitaxel (“Taxol”), 20 μM cytochalasin D (CytoD), and 30 μM nocodazole (Noc) were added to infected cells, and the cells were fixed at 18 h p.i. Cell surfaces were immunostained for HA (green) and then permeabilized and immunostained for NP (red). Inset shows a zoomed image of two cells connected by an intercellular connection. Viral NP is clearly visible within the connection (arrows) as well as in the cell body. (B) The bar graph quantifies the percentage of MDCK cell pairs with intercellular connections in drug-treated and control (DMSO) cells infected with IAV. *, P < 0.05. (C) The bar graph quantifies the percentage of MDCK cell pairs connected by intercellular connections in mock, PIV5, or IAV infections. ***, P < 0.001. Images were photographed on a confocal microscope. Scale bar, 20 μm.