Immunochemical Relationship of Human Plasma Beta-Lipoprotein and Chylomicrons

¹ From the Laboratory of Metabolism, National Heart Institute, National Institutes of Health, Bethesda, Maryland

S_f 3–8 human plasma beta-lipoprotein was prepared in the ultracentrifuge and was shown to be electrophoretically and ultracentrifugally homogeneous. Studies of this material with rabbit antisera to it indicated marked immunological inhomogeneity by agar gel diffusion and supernatant tests. Saline washed human chylomicrons reacted with the anti-beta-lipoprotein sera only after steapsin hydrolysis of the chylomicrons. No reaction between washed hydrolyzed chylomicrons and anti-human-serum-albumin rabbit serum was noted. Serial absorption studies indicated that chylomicrons and S_f 3–8 beta-lipoprotein are not immunologically identical but in the low density chylomicron fraction there is some substance antigenically related to S_f 3–8 beta-lipoprotein.