Selective and Efficient Immunoprecipitation of the Disease-associated Form of the Prion Protein Can Be Mediated by Nonspecific Interactions between Monoclonal Antibodies and Scrapie-associated Fibrils

Abstract

Transmissible spongiform encephalopathies are characterized by the accumulation in brain tissues of an abnormal isoform of the prion protein named PrPsc, which is the only direct marker known for transmissible spongiform encephalopathies. Here we show that PrPsc can be specifically immunoprecipitated by using several monoclonal antibodies (mAbs) of various specificities independently of the properties of their binding site (paratope). These results strongly suggest that a significant proportion of mAbs can interact with PrPsc aggregates through nonspecific paratope-independent interactions allowing selective immunoprecipitation of PrPsc when these mAbs are immobilized on a polydisperse solid phase like microbeads.

Immunotherapeutic effect of anti-PrP monoclonal antibodies in transmissible spongiform encephalopathy mouse models: pharmacokinetic and pharmacodynamic analysis

“…with 1 mg antibody (Table 1) three times at Table 1. mAb characteristics and pharmacokinetic data Linear epitopes recognized by the different mAbs were identified as described by Morel et al (2004). Antibodies for which no linear epitope was identified are categorized as 'unidentified', indicating that they bind a conformational epitope of PrP or another unknown antigen.…”

“…(i) 11C6/SAF83-AChE sandwiching to detect both full-length and N-terminally truncated PrPC, (ii) 11C6/SAF34-AChE sandwiching to detect only full-length PrPC, and (iii) SPIE-IA (Volland et al, 1999) with a SAF34/SAF34-AChE format to detect specifically N-terminal fragments after removal of full-length and N-terminally truncated PrPC by Sha31 immunoprecipitation (Morel et al, 2004).…”

“…mAbs are described in Table 1. Epitope mapping to identify linear epitopes was performed as described previously (Morel et al, 2004). All mAbs were used for passive immunization as dialysed and filtered ascitic fluid.…”

Human prion diseases: from antibody screening to a standardized fast immunodiagnosis using automation

“…15,16 They recognized different epitopes along the PrP sequence (Table 2). Monoclonal antibodies were purified using either caprylic acid precipitation 17 or protein A affinity chromatography.…”

“…Epitope mapping for identifying linear epitopes possibly recognized by monoclonal antibodies was performed as previously described. 16 3F4 antibody (ref. 9620) was produced and commercialized by Signet Laboratories (MA, USA).…”