Inference of intercellular spread of DENV by using a 1% methylcellulose-containing overlay.

<p>A-C) In the presence of 1% methylcellulose, a few infections appeared in the monolayer of C6/36 cells at 24 hpi while gradually enlarged aggregates of infected cells were observed at 48 and 72 hpi, respectively. D-F) Scattered infected cells are shown in the monolayer of C6/36 cells cultured in the medium only even when the virus was inoculated for 72 h. green: cells positive to antibodies against viral E protein; blue: cells stained with DAPI.