Anti-LRP/LR Antibody W3 Hampers Peripheral PrPSc Propagation in Scrapie Infected Mice

We identified the 37kDa/67kDa laminin receptor (LRP/LR) as a cell surface receptor for the cellular prion protein (PrPc) and the infectious prion protein (PrPSc). Recently, we showed that anti-LRP/LR antibody W3 cured scrapie infected N2a cells. Here, we demon strate that W3 delivered by passive immunotransfer into C57BL/6 mice reduced the PrPSc content in the spleen significantly by 66%, demonstrating an impairment of the peripheral PrPSc propagation. In addition, we observed a 1.8-fold increase in survival of anti-LRP/LR antibody W3 treated mice (mean survival of 31 days) compared to preimmune serum treated control animals (mean survival of 17 days). We conclude that the significant effect of anti-LRP/LR antibody W3 on the reduction of peripheral PrPSc propagation might be due to the blockage of the prion receptor LRP/LR which is required, as previously shown in vitro, for PrPSc propagation in vivo.