Expression of a transforming gene (E5) of bovine papillomavirus in sarcoids obtained from horses.
OBJECTIVE
To determine expression of a transforming gene (E5) of bovine papillomavirus in sarcoids, other tumors, and normal skin samples collected from horses with and without sarcoids.


METHODS
23 sarcoids and 6 samples of normal skin obtained from 16 horses with sarcoids, 2 samples of normal skin and 2 papillomas obtained from horses without sarcoids, and 1 papilloma obtained from a cow.


METHODS
Protein was extracted from tissue samples collected from horses and incubated with agarose beads covalently coupled to Staphylococcus aureus protein A and an anti-E5 polyclonal antibody. Following incubation, proteins were eluted from the beads and electrophoresed on a 14% polyacrylamide gel and transferred to a polyvinylidene difluoride membrane. The E5 protein was detected by use of western blot analysis, using a chemiluminescence detection system.


RESULTS
All 23 sarcoids had positive results for expression of E5 protein. Quantity of viral protein appeared to vary among sarcoids. All other tissues examined had negative results for E5 protein. Highest expression for E5 protein was observed in biologically aggressive fibroblastic variants of sarcoids, compared with expression in quiescent tumors.


CONCLUSIONS
This study documented that activation and expression of the E5 gene is evident in sarcoids obtained from horses. These data support the conclusion that infection with bovine papillomavirus is important in the initiation or progression of sarcoids in horses. Treatment strategies designed to increase immune recognition of virally infected cells are warranted.
Carr
E A
EA
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Théon
A P
AP
Madewell
B R
BR
Hitchcock
M E
ME
Schlegel
R
R
Schiller
J T
JT
D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D052688:Bovine papillomavirus 1 / Q000235:genetics* / Q000378:metabolism; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D015967:Gene Expression Regulation, Viral; D006734:Horse Diseases / Q000473:pathology / Q000821:virology*; D006736:Horses; D009856:Oncogene Proteins, Viral / Q000096:biosynthesis / Q000235:genetics*; D030361:Papillomavirus Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011233:Precipitin Tests / Q000662:veterinary; D012507:Sarcoidosis / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D012874:Skin Diseases, Infectious / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D014158:Transcription, Genetic / Q000235:genetics; D014412:Tumor Virus Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology
D004279:DNA, Viral; D009856:Oncogene Proteins, Viral; C054304:oncogene protein E5, Bovine papillomavirus type 1