The DNA assisted solid-phase proximity ligation assay (SP-PLA) provides a unique opportunity to specifically detect prion protein (PrP) aggregates by investigating the collocation of 3 or more copies of the specific protein. We have developed an SP-PLA that can detect PrP aggregates in brain homogenates from infected hamsters even after a 10(7)-fold dilution. In contrast, brain homogenate from uninfected animals did not generate a detectable signal at 100-fold higher concentration. Using either of the 2 monoclonal anti-PrP antibodies, 3F4 and 6H4, we successfully detected low concentrations of aggregated PrP. The presented results provide a proof of concept that this method might be an interesting tool in the development of diagnostic approaches of prion diseases.
Keywords: 263K; BSE, bovine spongiform encephalopathy; CJD, Creutzfeldt-Jakob disease; CSF, cerebrospinal fluid; FIDA, fluorescence intensity distribution analysis; PLA, proximity ligation assay; PMCA, protein misfolding cyclic amplification; PrP, prion protein; PrPC, cellular prion protein; PrPSc, scrapie prion protein; QuIC, quaking-induced conversion; SP-PLA, solid phase proximity ligation assay; diagnosis; monoclonal antibody; prion protein; proximity ligation assay; qPCR, quantitative real-time PCR.