Intestinal uptake of amyloid beta protein through columnar epithelial cells in suckling mice.

The mechanism of transmission of amyloid protein, especially the dynamics in the intestine, is still largely unknown. In the present study, a fusion protein (Abeta-EGFP) that combined enhanced green fluorescent protein with amyloid-beta protein (Abeta) was orally administered to mice before and after weaning, and the uptake and kinetics of amyloid protein within the intestine were elucidated through histopathology. Abeta-EGFP was incorporated into the cytoplasm of columnar epithelial cells, rather than M cells, at 3 h after administration and thereafter. Abeta-EGFP then accumulated in the crypt, Peyer's patch, and even the spleen. However, this uptake was not observed in weaned mice. These results suggest that a specific tolerant mechanism for incorporation of Abeta escaped from the digestion exists during suckling periods. This age-dependent uptake is important for estimating the risk of transmission.