Fig. 1.

Macaque astrocytes are susceptible to Asian- and African-lineage ZIKV infection. Immunofluorescence images (40×) of primary astrocytes isolated and cultured from the brain tissue of a naïve infant rhesus macaque (animal A). Astrocytes were either left uninfected a or infected with the Asian-lineage strain Rio-U1 b and d or the African-lineage strain MR766 c and e and stained at 3 dpi for the astrocyte marker GFAP-CY3 in red a–e, the viral proteins envelope (ENV) a–c or nonstructural protein 3 (NS3) d–e in green, and the cell nucleus by DAPI in blue. Double labeled cells with both GFAP-CY3 and viral protein-positive labeling appear yellow (overlay image, rightmost column). For quantification, 10-high-power-fields were used to count DAPI positive nuclei for total cells and calculate percentages of GFAP, ENV, or NS3 positive cells as well as double-labeled GFAP/ENV or GFAP/NS3