Immunohistochemical analysis
For immunohistochemical analysis, tissue samples (including spleens, tonsils, and gastrohepatic lymph nodes) were collected from ASFV infected pigs and fixed in 10% formalin for 24 h at room temperature. Slides were prepared following a common procedure of dehydration, embedding, and section. The slides were dried in oven at a temperature of 56℃ for 15 min, incubated with 3% perhydrol liquid at room temperature and blocked with 5% Difco Skim Milk for 1h at room temperature, incubated with 1:100 of mAbs at 4℃ overnight. After five washes with TBST, the slides were incubated with a goat anti-mouse IgG (Invitrogen, USA) (1:100) for 30 min at 37℃. The slides were stained with ST Hematoxylin (Leica, Germany) and analyzed using a microscope (DFC550, Leica, Germany).