CD21-Positive Follicular Dendritic Cells A Possible Source of PrP^Sc in Lymph Node Macrophages of Scrapie-Infected Sheep

Authors

Lynn M. Herrmann, U.S. Department of Agriculture
William P. Cheevers, Washington State University
William C. Davis, Washington State University
Donald P. Knowles, USDA-ARSFollow
Katherine I. O'Rourke, U.S. Department of AgricultureFollow

Document Type

Article

Date of this Version

2003

Comments

Published in American Journal of Pathology, Vol. 162, No. 4, April 2003

Abstract

Natural sheep scrapie is a prion disease characterized by the accumulation of PrP^Sc in brain and lymphoid tissues. Previous studies suggested that lymph node macrophages and follicular dendritic cells (FDC) accumulate PrP^Sc. In this study, lymph nodes were analyzed for the presence of PrP^Sc and macrophage or FDC markers using dual immunohistochemistry. A monoclonal antibody (mAb) to the C-terminus of PrP reacted with CD172a+ macrophages and CD21+ FDC processes in secondary follicles. However, a PrP N-terminus- specific mAb reacted with CD21+ FDC processes but not CD172a+ macrophages in secondary follicles. Neither the PrP N-terminus nor C-terminus-specific mAb reacted with CD172a+ macrophages in the medulla. These results indicate that lymph node follicular macrophages acquire PrP^Sc by phagocytosis of CD21+ FDC processes. The results also suggest that follicular macrophages have proteases that process full-length PrP^Sc to N-terminally truncated PrP^Sc.