Immunohistological evaluation on respiratory lesions of pigs intranasally inoculated with Actinobacillus pleuropneumoniae serotype 1

• Published in: Journal of Veterinary Medical Science Vol. 58; no. 4; pp. 297 - 303
• Main Authors: Ajito, T. (Iwate Univ., Morioka (Japan). Faculty of Agriculture), Haga, Y, Homma, S, Goryo, M, Okada, K
• Format: Journal Article
• Language: English
• Published: Japan JAPANESE SOCIETY OF VETERINARY SCIENCE 01.04.1996; Japan Science and Technology Agency
• Subjects: Actinobacillus Infections - immunology; Actinobacillus Infections - pathology; ACTINOBACILLUS PLEUROPNEUMONIAE; Actinobacillus pleuropneumoniae - classification; Actinobacillus pleuropneumoniae - isolation & purification; ANALISIS HISTOCITOLOGICO; ANALYSE HISTOCYTOLOGIQUE; Animals; Antibodies, Bacterial - blood; ANTIGENE; ANTIGENOS; ANTIGENS; Antigens, Bacterial - analysis; CERDO; ELISA; HISTOCYTOLOGICAL ANALYSIS; HISTOPATHOLOGIE; HISTOPATHOLOGY; HISTOPATOLOGIA; IMMUNOENZYME TECHNIQUES; immunohistochemistry; IMMUNOLOGICAL TECHNIQUES; Lung - microbiology; Lung - pathology; Lymph Nodes - immunology; Lymph Nodes - microbiology; Organ Specificity; Palatine Tonsil - microbiology; Palatine Tonsil - pathology; Pleural Effusion - microbiology; PLEURONEUMONIA; PLEUROPNEUMONIA; Pleuropneumonia - immunology; Pleuropneumonia - pathology; PLEUROPNEUMONIE; PORCIN; Serotyping; SWINE; TECHNIQUE IMMUNOENZYMATIQUE; TECHNIQUE IMMUNOLOGIQUE; TECNICAS INMUNOENZIMATICAS; TECNICAS INMUNOLOGICAS; TEST ELISA
• ISSN: 0916-7250; 1347-7439
• DOI: 10.1292/jvms.58.297

Nine-week-old pigs were inoculated intranasally with 6.10 x 10(3) (group 3), 10(5) (group 5) and 10(7) (group 7) colony forming unit of Actinobacillus pleuropneumoniae (App) serotype 1 designated HA-337 strain, respectively. One pig in group 5 and 2 pigs in group 7 died with dispnea and hemorrhagic pleuropneumonia within 20 to 48 hr post inoculation (PI). All pigs necropsied on 7 days in groups 5 and 7 had focal fibrous pleuropneumonia. Histologically, pulmonary lesions were classified into three stages; peracute, acute and subacute. Fatal cases in group 7 had peracute lesion composed of severe edema, hemorrhage and necrobiosis of alveoli, with mononuclear cells infiltration in the dilated interlobulus. The fatal case in group 5 had acute pulmonary lesion composed of focal or linear infiltration of round and fusiform cells that frequently showed swirling pattern in alveoli. The surviving cases in group 5 and 7 had subacute lesion composed of multifocal pulmonary necrosis surrounded by fibrous tissue. The swirling pattern was clearly seen in demarcation zone. Immunohistochemically, App antigens scattered as intact bacteria in alveoli, dilated interlobular septa and pleura, and lymph vessels in peracute and acute lesions. Areas of necrosis were also stained weakly. Although no antigen was detected in cytoplasm of macrophages and infiltrated cells in peracute lesions, App antigen was detected as positively stained mass in cytoplasm of some macrophages in acute lesions. In subacute lesions, App antigens were recognized as intact bacteria in necrotic areas and among the swirling pattern cells of demarcation zone. Macrophages had App antigens as a large mass of pigment in the cytoplasm in area of fibrosis