Apoptosis in calf pneumonia induced by endobronchial inoculation with bovine adenovirus type 3 (BAV-3).
Three calves aged 1 week (group 1), three aged 6 weeks (group 2) and three aged 6 weeks (having been pretreated with dexamethasone) (group 3) were infected endobronchially with bovine adenovirus type 3 (BAV-3). All calves had received colostrum. The histopathological, immunohistochemical, ultrastructural and TUNEL features were examined on post-inoculation day (PID) 3, 5 and 7. Viral replication and intranuclear inclusions were frequently observed in groups 1 and 3, but not in group 2. The lesions became progressively severe on PID 5 and 7 in group 1. In group 3, however, the cellular injury caused by BAV-3 was of short duration and the lesions began to resolve at PID 7. Numerous apoptotic cells were seen in the PID 3 calves of all three groups, and in the PID 7 calves of groups 2 and 3; however, the PID 5 and 7 calves of group 1 showed only a few apoptotic cells in the alveolar septa. The results indicated that (1) the durability of BAV-3 infection in the lung was closely related to apoptosis, and (2) the host defence mechanism that induced apoptosis in infected cells was age-related.
Yamada
M
M
National Institute of Animal Health, Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
Narita
M
M
Nakamura
K
K
Tsuboi
T
T
Kawashima
K
K
D000818:Animals; D000831:Animals, Newborn; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D017209:Apoptosis; D002417:Cattle; D002418:Cattle Diseases / Q000209:etiology / Q000473:pathology* / Q000635:transmission; D004249:DNA Damage; D003907:Dexamethasone / Q000494:pharmacology; D016867:Immunocompromised Host; D007124:Immunoenzyme Techniques / Q000662:veterinary; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D007181:Inclusion Bodies, Viral / Q000648:ultrastructure; D008168:Lung / Q000648:ultrastructure / Q000821:virology; D008297:Male; D017921:Mastadenovirus / Q000472:pathogenicity / Q000502:physiology*; D011024:Pneumonia, Viral / Q000209:etiology / Q000473:pathology / Q000635:transmission / Q000662:veterinary*; D014779:Virus Replication
D000893:Anti-Inflammatory Agents; D003907:Dexamethasone