Modification of PCV-2 virulence by substitution of the genogroup motif of the capsid protein

Allemandou, Aude; Grasland, Béatrice; Hernandez-Nignol, Anne-Cécile; Kéranflec'h, André; Cariolet, Roland; Jestin, André

Samples from tracheo-bronchial and inguinal lymph nodes, tonsils, lung and liver were fixed in formalin for histological examination. The microscopic lesions were assessed on haemalun-eosin-safranin stained tissue section. The microlesions were assessed by a person not aware of the treatment received by the piglets, in lymphoid organs (represented by lymphocyte depletion and presence of inflammation) and in the lungs (presence of interstitial pneumonia) and each scored from absence (0) to severe (3) . Then the score means per group were calculated using the microlesion score in the tracheobronchial lymph nodes, inguinal lymph nodes and the lungs. The presence of PCV-2 antigens was detected by immunochemistry on fixed tissue sections (tracheobronchial and inguinal lymph nodes, tonsils, lung and liver) as previously described [21] using a rabbit anti-PCV-2b polyclonal serum.