FIG. 3.

Well-differentiated BAEC infected by BPIV3 (A) or BRSV (B). (A) BPIV3 was applied to the apical surface at an MOI of 0.1 for 2 h. At 2 dpi, cultures were fixed and cilia were visualized by staining for β-tubulin (red). Virus-infected cells were detected by immunostaining (green). (B) BRSV infection of pseudostratified epithelia of BAEC. Infected cells were fixed 3 (left and right panels) and 10 (middle panels) dpi, respectively, and stained with an antibody recognizing β-tubulin (red). Virus-infected cells were visualized by GFP expression (green). BRSV applied at an MOI of 0.1 (left and middle panels) predominantly infected cells in the border area of the filter, where differentiation was less developed (white arrow, top panels). The infected cells were not ciliated (bottom panels, higher magnification). When virus was applied at an MOI of 3.5 (right panels), BRSV-infected well-differentiated BAEC cells were distributed all over the filter (top panel, lower magnification), including ciliated cells (bottom panel, higher magnification).