Scattered columnar epithelial cells had OX6 immunoreactivity at 2 days after infection (Fig. 4B) , and the number increased progressively (Fig. 4C) . By 1 week, most of the epithelium had granular OX6 immunoreactivity, which appeared to be associated with intracellular organelles (Fig. 4C) . No epithelial cells were stained when the OX6 primary antibody was omitted.