Figure 4: Infection of microglia culture (free from astrocytes) with RSA59 demonstrates syncytia formation. Purified microglial cultures from the neonatal mixed glia were stained with anti-CD11b conjugated to Cy3 and anti-GFAP (astrocyte marker). Three different cultures were immunostained but the best representative culture is shown in (a). Immunostained culture demonstrates that majority of the isolated cells are microglia (positive for CD11b-Cy3) and negative for astrocytes (GFAP-negative). Purified cultures were infected with RSA59 at 2 : 1 M.O.I, and after 24 hrs postinfected cultures were observed under epifluorescence microscope. At 24 hrs postinfection, the majority of the cells were infected and most of the infected cells form syncytia (b, c). DAPI staining of infected cells shows the nucleus in the syncytia (b) and EGFP fluorescence demonstrates the RSA59 infection (c). Five culture plates were infected but the representative infected culture is shown here.