NDP and infection: In contrast, in those permissive infections leading to high gene expression, as MVMp in NB324K and Nd in U373MG upon treatment with low doses of α2-3 S or α2-3,6,8 NAs, the virions showed a striking pattern of accumulation in clusters that could be localized by confocal IF within the endosomal contour delineated by the EEA-1 early marker (Figure 6, Supplementary Figure S4, lower panels).