Test for detection of disease-associated prion aggregate in the blood of infected but asymptomatic animals.
We have developed a sensitive in vitro assay for detecting disease-associated prion aggregates by combining an aggregation-specific enzyme-linked immunosorbent assay (AS-ELISA) with the fluorescent amplification catalyzed by T7 RNA polymerase technique (FACTT). The new assay, named aggregation-specific FACTT (AS-FACTT), is much more sensitive than AS-ELISA and could detect prion aggregates in the brain of mice as early as 7 days after an intraperitoneal inoculation of PrP(Sc). However, AS-FACTT was still unable to detect prion aggregates in blood of infected mice. To further improve the detection limit of AS-FACTT, we added an additional prion amplification step (Am) and developed a third-generation assay, termed Am-A-FACTT. Am-A-FACTT has 100% sensitivity and specificity in detecting disease-associated prion aggregates in blood of infected mice at late but still asymptomatic stages of disease. At a very early stage, Am-A-FACTT had a sensitivity of 50% and a specificity of 100%. Most importantly, Am-A-FACTT also detects prion aggregates in blood of mule deer infected with the agent causing a naturally occurring prion disease, chronic wasting disease. Application of this assay to cattle, sheep, and humans could safeguard food supplies and prevent human contagion.
Chang
Binggong
B
Institute of Pathology School of Medicine, Case Western Reserve University, Cleveland, Ohio 44107-1712, USA.
Cheng
Xin
X
Yin
Shaoman
S
Pan
Tao
T
Zhang
Hongtao
H
Wong
Poki
P
Kang
Shin-Chung
SC
Xiao
Fan
F
Yan
Huimin
H
Li
Chaoyang
C
Wolfe
Lisa L
LL
Miller
Michael W
MW
Wisniewski
Thomas
T
Greene
Mark I
MI
Sy
Man-Sun
MS
D000818:Animals; D003670:Deer; D007118:Immunoassay; D051379:Mice; D018620:PrPSc Proteins / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D017096:Prion Diseases / Q000097:blood* / Q000276:immunology / Q000662:veterinary*; D011328:Prions / Q000097:blood* / Q000737:chemistry / Q000276:immunology*
D018620:PrPSc Proteins; D011328:Prions