title: Immunohistochemical staining of IFN-gamma positive cells in porcine reproductive and respiratory syndrome virus-infected lungs.
abstract: Paraffin-embedded lungs were obtained from a previous porcine reproductive and respiratory syndrome virus (PRRSV)-challenged experiment involving three groups: an uninfected control group, a low virulence (LV, Resp PRRSV/Repro)-infected group, and a high virulence (HV, VR-2385)-infected group. Tissues were collected at 3, 7, 10, 14 or 28 days post-inoculation (DPI) (n=5). Lungs were examined to detect IFN-gamma positive cells by immunohistochemical staining using polyclonal antibodies to IFN-gamma. The microscopic lung lesions induced by the HV group were more severe than those in the LV group. A significant increase in number of lymphocytes in the HV group was observed at 10 DPI (24.90+/-9.79%), 14 DPI (22.00+/-11.47%) and 28 DPI (28.95+/-15.11%) (P<0.05). A relative decrease in macrophage numbers was observed and correlated well with the increase in lymphocyte numbers when the disease progressed. IFN-gamma positive cells were demonstrated in both lymphocytes and macrophages, particularly pulmonary alveolar macrophages. A significant increase in IFN-gamma positive cells was found at 7 DPI (15.90+/-13.65%), 10 DPI (46.95+/-13.79%), 14 DPI (10.90+/-5.13%) and 28 DPI (13.40+/-4.89%) in the HV group (P<0.05). The results suggested that the increase in IFN-gamma positive cells in the HV group correlated well with the severity of the lung lesions, which may be because of the presence of PRRSV in the lung.
authors.affiliation: Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand. roongroje.t@chula.ac.th
authors.forename: Roongroje
authors.initials: R
authors.lastname: Thanawongnuwech
authors.forename: Anudep
authors.initials: A
authors.lastname: Rungsipipat
authors.forename: Sirilak
authors.initials: S
authors.lastname: Disatian
authors.forename: Rungrat
authors.initials: R
authors.lastname: Saiyasombat
authors.forename: Sudarat
authors.initials: S
authors.lastname: Napakanaporn
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Halbur
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis*; D008168:Lung / Q000276:immunology* / Q000821:virology*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology*; D013552:Swine; D014779:Virus Replication
chemical_list: D007371:Interferon-gamma