Interaction between Trypanosoma brucei and the ependymal cell of the choroid plexus.

The fine structure of the normal choroid plexus of rats and mice and of those infected with Trypanosoma brucei was examined by transmission and scanning electron microscopy: extracellular trypomastigotes in the perivascular stroma predominate but the evidence presented suggests that they are derived both from stages in the blood and from others undergoing division within ependymal cells, a process which results in destruction of a large proportion of ependymal cells in the parts of choroid plexus affected. The choroid plexus maintains its integrity by regeneration of an outer layer of ependymal cells.