Isolation and characterization of an antigenically distinct 68-kd protein from nonviral intracytoplasmic inclusions in Boa constrictors chronically infected with the inclusion body disease virus (IBDV: Retroviridae).
The relationship between a retroviral infection and the development of nonviral intracytoplasmic inclusion bodies was studied in a Boa constrictor model. Twelve juvenile age- and size-matched inclusion body disease (IBD)-negative boas were randomly divided into three groups. Each group was inoculated intraperitoneally with 1 ml of an IBD virus (IBDV)-infected liver homogenate or 1 ml of normal boa liver homogenate (sham-inoculated control) or was left untreated. All boas were monitored for development of IBD by daily examination and serial liver biopsy over 1 year. The 4 IBDV-inoculated boas became IBDV and inclusion positive by 10 weeks postinoculation. The average size and density of inclusion bodies increased with the duration of infection. Ultrastructurally, inclusion bodies <2 microm in diameter consisted of intracytoplasmic aggregates of granular electron-dense material that were not membrane limited. Larger inclusions (3-6 microm in diameter) were characterized as membrane-bound aggregates of amorphous to granular electron-dense material admixed with membranelike fragments. The sham-inoculated and untreated control snakes did not become inclusion or IBDV positive. Direct comparison of the protein electrophoretograms of IBDV-infected and normal boa tissues demonstrated a prominent 68-kd protein band unique to infected inclusion-positive tissues. Monoclonal antibodies directed against the 68-kd protein band specifically labeled inclusion bodies. The results of this study demonstrate that IBD inclusions represent an intracytoplasmic accumulation of an antigenically distinct IBDV-associated protein.
Wozniak
E
E
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, USA.
McBride
J
J
DeNardo
D
D
Tarara
R
R
Wong
V
V
Osburn
B
B
D000818:Animals; D000956:Antigens, Viral / Q000302:isolation & purification*; D001706:Biopsy / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D017821:Boidae / Q000821:virology*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005065:Euthanasia / Q000662:veterinary; D005260:Female; D002479:Inclusion Bodies / Q000473:pathology* / Q000648:ultrastructure / Q000821:virology; D007668:Kidney / Q000473:pathology; D008099:Liver / Q000473:pathology* / Q000648:ultrastructure / Q000821:virology; D051379:Mice; D016253:Microscopy, Immunoelectron / Q000662:veterinary; D008970:Molecular Weight; D011897:Random Allocation; D012190:Retroviridae / Q000276:immunology / Q000302:isolation & purification / Q000648:ultrastructure; D012192:Retroviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology
D000956:Antigens, Viral