Fig. 1.

The characteristics of IBV replication in HD11 cells (A) Cells were fixed at 24 h, and virally infected cells were visualized by immunofluorescence (IF) staining of IBV N protein (green). Cell nuclei were visualized by DAPI staining. (B) Proliferation curve of IBV in HD11 cells. Virus titers were measured by TCID₅₀ at every 6 h after infection. Each measurement was performed in triplicate and the error bars represent the standard deviation. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)