Figure 1

IBV infected cell quantification (A) and antigen expression (B) in tracheal mucosa explants. A Number of IBV B1648 and M41 infected cells and infected KUL01⁺ cells were quantified in the epithelial layer and lamina propria of tracheal mucosa explants. Fifteen consecutive cryosections were analysed at 0, 6, 12, 24, 48 and 72 hpi to quantify infected cells. The number of infected KUL01⁺cells starts to increase from 12 hpi, when the total number of IBV infected cells starts to decrease. Lines represent the evolution of arithmetic means without any transformation of original data. Solid line represents mean values of B1648, dashed line represents mean values of M41 and dotted line represents mean values of mock. An asterisk (*) indicates a significant difference (P < 0.05) between B1648 and M41. B Representative confocal photomicrograph illustrating IBV infected cells (left panel) in the epithelium (arrows) and lamina propria (arrowheads), and IBV infected KUL01⁺cell (middle panel) in lamina propria (arrowhead) of the tracheal mucosa. Mock-inoculated tracheal mucosa (right panel). Green fluorescence visualises IBV antigens. KUL01⁺ cells are visualised by red fluorescence. Cell nuclei were stained with Hoechst (blue). White dotted line indicates the BM. Scale bar represents 50 μm.