[Nature of the lipoprotein antigen responsible for the development of resistance to experimental atherosclerosis following its use in immunization of newborn rabbits].

In order to develop a tolerance to experimental atherosclerosis newborn rabbits were immunized with various fractions of atherogenic lipoproteins (lipoproteins of low density, lipoproteins of very low density and total fraction of these lipoproteins), isolated from blood serum of adult rabbits with experimental hypercholesterolemia. The tolerance to atherosclerosis proved to be achieved in immunization with lipoproteins of very low density. The lesser effect was observed using the total fraction of lipoproteins.

[Cholesterol metabolism in rabbits with resistance to experimental atherosclerosis acquired by immunological treatment].

Development of resistance to experimental atherosclerosis due to immunization of newborn rabbits with homologous fraction of beta- and pre-beta-lipoproteins was accompanied by increased oxidation of cholesterol to biliary acids and by accelerated excretion of cholesterol. The phenomenon appears to be caused by two mechanisms: 1 (cholesterol, occurring in the fraction of free lipoproteins "unblocked" by the antibody (immunzied animals), is more readily oxidized to biliary acids in liver tissue than cholesterol, occurring in the autoimmune complex "lipoprotein-antibody" (non-immunized animals)); 2) the enzymes and biological systems, responsible for elimination of cholesterol from an organism (oxidation to biliary acids, excretion with bile), are activated after immunization of the newborn animals by the lipoprotein fraction endriched with cholesterol.