Figure 5

Photomicrograph of the main immune system. Photomicrograph of the main immune system involving in spleen, tonsil, hilar lymph nodes, mesenteric lymph nodes and inguinal lymph nodes collected from experimental groups weaned piglets euthanized at different days post inoculation porcine TTSuV2. With the development of infection, the sections of tonsil, spleen, hilar lymph nodes and mesenteric lymph nodes showed the normal architecture with no special lesions through the study but only rarely red blood cells in the microvasculation and infiltration of inflammatory cells (lymphocytes and eosinophils) of tonsiland hilar lymph nodes marked by black arrowheads (m, o, p, s. HE. ×100; n, t. HE. ×200; r. HE. ×400). In addition, inguinal lymph nodes' architecture was normal, but congestion, infiltration of inflammatory lymphocytes and necrosis or degeneration and focal gliosis of lymphocytes in the paracortical zone were observed at 24 dpi. (u. HE. ×100; v. HE. ×200). The red four-point star, five-point star and rhomboid represent the normal architecture of those immune organs.