2.7∣Histological examination of delayed-type reaction
On day 61, experimental animals were intradermally challenged with rFor
t 2 and videotaped immediately. After 48 hours, the mice were sacrificed
and the abdominal skins from the challenge sites were removed and placed
in 10% formalin overnight at room temperature. Briefly, tissues were
embedded in paraffin, cut into 5-μm sections, de-paraffinized,
dehydrated, and stained with hematoxylin and eosin (H&E). All slides
were recorded under a Hamamastu nanozommer 2.0 HT slide scanner
(Hamamastu, Japan) at 400-fold magnification. The numbers of different
infiltrated cells in dermis were counted at 400-fold magnification by
light microscopy.