NR AWIB
AU Koren,S.; Kosmac,M.; Pretnar Hartman,K.; Vranac,T.; Curin Serbec,V.
TI Immunisation with a human prion protein peptide stimulates generation of identical PrPsc-specific antibodies in distinct mice
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions S-12
PT Konferenz-Poster
AB A crucial feature of all transmissible spongiform encephalopathies (TSE) is the conversion of cellular prion protein (PrPc) to the disease-associated misfolded isoform (PrPsc). All current TSE diagnostic assays are based on the detection of PrPsc. Our group previously reported on the successful attempt to produce PrPsc-specific monoclonal antibody (mAb) by immunisation of wild type Balb/c mice with a 13 amino acid peptide from the C-terminal region of PrP, bound to keyhole limpet hemocyanin (KLH). Further experiments involving immunization with the same antigen showed that generation of conformationally sensitive, PrPsc-specific antibodies was reproducible. In fact, most of the obtained mAbs specifically recognized the PrPsc isoform. In this study we sequenced and compared light and heavy chain variable regions of several PrPsc-specific mAbs. Molecular modelling was used to predict the structure of antigen binding sites. As all investigated antibodies were obtained by the same strategy and most of them showed very similar specificity, we expected to find common binding site features. Remarkably, in two separate cases, antibodies with absolutely identical variable regions were found. In both cases matching mAbs originated from distinct cell fusion experiments, i.e. they were originally produced by distinct mice. Sequences of other mAbs involved in the study showed considerably more differences, although the degree of sequence similarity agreed with the observed similarities in antigen-binding properties. Generation of identical antibodies might be explained by the well-known immune tolerance to PrP. We suggest that the repertoire of conformationally sensitive antibodies that are able to recognize the peptide, but at the same time do not cross-react with selfPrP, is very limited. Selection for high-affinity antibodies, first by the immune system itself, and later by hybridoma screening, further reduces their number.
AD Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia. E-mail: simon.koren@ztm.si
SP englisch
PO Italien