title: Immunoreactivity and morphological changes of bursal follicles in chickens infected with vaccine or wild-type strains of the infectious bursal disease virus.
abstract: Infectious bursal disease (IBD) is characterized by immunosuppression due to the depletion of lymphocytes in the atrophied bursa of Fabricius (BF). We have sometimes encountered contradictory findings: chickens infected with the vaccine IBD virus (IBDV) strain have sometimes exhibited a highly atrophied BF, but not immunosuppression. In this study, chickens administered vaccine or wild-type strains of IBDV were later vaccinated with the B1 strain of the Newcastle disease virus (NDV). Bursal changes were examined histologically with a focus on the bursal follicle. The immunoreactivity to NDV was also evaluated with the hemagglutination inhibition test. In gross examination, we observed a few chickens with a severely atrophied BF in vaccine strain-administered groups (vaccine groups), and the level of severity was the same as that in the wild-type strain-administered group (wild-type group). However, these chickens retained humoral antibody responses to NDV and were revealed to possess a higher number of bursal follicles than those of the wild-type group. These results indicated that macroscopic evaluation dose not accurately reflect the immunoreactivity and degree of bursal damage in IBDV-administered chickens. We also found non-immunosuppressed chickens in the wild-type group. These non-immunosuppressed chickens retained a significantly higher number of normal follicles and total follicles according to our statistical analysis. Furthermore, a high correlation coefficient between the NDV-HI titer and the number of normal follicles was found in the wild-type group. These results implied that the retained number of normal follicles is important for the immunoreactivity of chickens infected with IBDV.
authors: National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan.
authors: Naoyuki
authors: N
authors: Aihara
authors: Noriyuki
authors: N
authors: Horiuchi
authors: Nanase
authors: N
authors: Hikichi
authors: Mariko
authors: M
authors: Ochiai
authors: Yuko
authors: Y
authors: Hosoda
authors: Yoko
authors: Y
authors: Ishikawa
authors: Yoko
authors: Y
authors: Shimazaki
authors: Koji
authors: K
authors: Oishi
mesh_terms: D000818:Animals; D018175:Birnaviridae Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D002060:Bursa of Fabricius / Q000276:immunology / Q000473:pathology*; D002645:Chickens / Q000276:immunology / Q000821:virology; D007243:Infectious bursal disease virus / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology / Q000473:pathology / Q000821:virology*; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D014765:Viral Vaccines