[Morphological characteristics of the brain lesions in mice infected with a homogenate of L cells latently infected with the scrapie agent].

Degeneration of neurons of the Ammon horn lower branch both in the early and terminal stages of the disease of mice infected with the homogenate of L cells latently infected with the scrapie agent (the L-S system) was frequently detected alongside with brain lesions typical of slow infections (vacuolation). Examinations of chromosomes in metaphase plates of L-S cells carried out by several methods including the TAC system for texture analysis of the image (Leutz, BRD) revealed three marker chromosomes new for continuous L cells, the appearance of true chromatid translocations as well as significant changes in chromosome numbers. Besides, ultrastructural features of L-S cells at later stages of cultivation were revealed. It is assumed that the active effect of the scrapie agent on L cells infected with it resulted in the emergency of a new antigen capable to induce selective affection of the neurons of the Ammon horn lower branch in susceptible mice.