IMPY, a potential beta-amyloid imaging probe for detection of prion deposits in scrapie-infected mice.
BACKGROUND
A potential single-photon emission computed tomography imaging agent for labeling of A beta plaques of Alzheimer's disease, IMPY (2-(4'-dimethylaminophenyl)-6-iodo-imidazo[1,2-a]pyridine), would be effective in detection of prion amyloid deposits in transmissible spongiform encephalopathies (TSEs).


METHODS
In vitro autoradiographic studies were carried out with [125 I]IMPY on brain sections from scrapie-infected mice and age-matched controls. Competition study was performed to evaluate the prion deposit binding specificity with nonradioactive IMPY.


RESULTS
Binding of [125 I]IMPY was observed in infected brain sections, while on age-matched control brain sections, there was no or very low labeling. Prion deposit binding was confirmed by histoblots with prion protein-specific monoclonal antibody 2D6. In the presence of nonradioactive IMPY, the binding of [125 I]IMPY was significantly inhibited in all regions studied.


CONCLUSIONS
These findings indicate that IMPY can detect the prion deposits in vitro in scrapie-infected mice. Labeled with 123 I, this ligand may be useful to quantitate prion deposit burdens in TSEs by in vivo imaging.
Song
Pu-Jiao
PJ
INSERM, U619, F-37000 Tours, France.
Bernard
Serge
S
Sarradin
Pierre
P
Vergote
Jackie
J
Barc
Céline
C
Chalon
Sylvie
S
Kung
Mei-Ping
MP
Kung
Hank F
HF
Guilloteau
Denis
D
D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D004195:Disease Models, Animal; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D007553:Isotope Labeling / Q000379:methods*; D051379:Mice; D058225:Plaque, Amyloid / Q000000981:diagnostic imaging* / Q000473:pathology; D011328:Prions / Q000737:chemistry*; D011720:Pyrazoles / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012608:Scrapie / Q000000981:diagnostic imaging* / Q000473:pathology
D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes; D011328:Prions; D011720:Pyrazoles; D019275:Radiopharmaceuticals; C000971:2,3-dihydro-1H-imidazo(1,2-b)pyrazole