PrP(Sc) detection and infectivity in semen from scrapie-infected sheep.
A scrapie-positive ewe was found in a flock that had been scrapie-free for 13 years, but housed adjacent to scrapie-positive animals, separated by a wire fence. Live animal testing of the entire flock of 24 animals revealed seven more subclinical scrapie-positive ewes. We hypothesized that they may have contracted the disease from scrapie-positive rams used for breeding 4 months prior, possibly through the semen. The genotypes of the ewe flock were highly scrapie-susceptible and the rams were infected with the 'Caine' scrapie strain having a short incubation time of 4.3-14.6 months in sheep with 136/171 VQ/VQ and AQ/VQ genotypes. PrP(Sc) accumulates in a variety of tissues in addition to the central nervous system. Although transmission of prion diseases, or transmissible spongiform encephalopathies, has been achieved via peripheral organ or tissue homogenates as well as by blood transfusion, neither infectivity nor PrP(Sc) have been found in semen from scrapie-infected animals. Using serial protein misfolding cyclic amplification followed by a surround optical fibre immunoassay, we demonstrate that semen from rams infected with a short-incubation-time scrapie strain contains prion disease-associated-seeding activity that generated PrP(Sc) in sPMCA (serial protein misfolding cyclic amplification). Injection of the ovinized transgenic mouse line TgSShpPrP with semen from scrapie-infected sheep resulted in PrP(Sc)-seeding activity in clinical and, probably as a result of the low titre, non-clinical mouse brain. These results suggest that the transmissible agent, or at least the seeding activity, for sheep scrapie is present in semen. This may be a strain-specific phenomenon.
Departments of Neurology and Physiology/Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
Richard
R
Rubenstein
University of Idaho, Caine Veterinary Teaching and Research Center, 1020 E. Homedale Road, Caldwell, ID 83607, USA.
Marie S
MS
Bulgin
Departments of Neurology and Physiology/Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
Binggong
B
Chang
University of Idaho, Caine Veterinary Teaching and Research Center, 1020 E. Homedale Road, Caldwell, ID 83607, USA.
Sharon
S
Sorensen-Melson
Departments of Pathology Neuroscience, and Neurology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44120, USA.
Robert B
RB
Petersen
New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
Giuseppe
G
LaFauci
D000818:Animals; D001947:Breeding; D005260:Female; D005838:Genotype; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018620:PrPSc Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D012608:Scrapie / Q000175:diagnosis / Q000378:metabolism / Q000635:transmission*; D012661:Semen / Q000737:chemistry* / Q000378:metabolism; D012756:Sheep; D034561:Sheep, Domestic
D018620:PrPSc Proteins