On the Antigenic Identity of Human Serum Beta and Alpha-2 Lipoproteins, and Their Identification in the Aortic Intima

Abstract

By the use of immunoelectrophoresis, it was demonstrated that ultracentrifugally isolated, very-low-density (alpha-2) lipoproteins migrate faster toward the anode in electro-phoresis and diffuse more slowly in agar than do low-density (beta) lipoproteins. However, these two lipoprotein fractions were found to be antigenically indistinguishable with this technique. Extracts of the intima of aortas were shown to contain material with all the physical properties consistent with those of the low-density (beta) lipoproteins. Further-more, this was the only serum protein which was consistently found in high concentration in washed aortas. Beta lipoprotein was frequently found in plaque-free intimae. The impression was obtained that this lipoprotein was present in greater concentration in early atheromatous plaques than in plaque-free intimae, and that it was much more concentrated in the intimae of severely sclerotic aortas than in those of moderately or uninvolved aortas. However, it has not been demonstrated in the gruel from far-advanced plaques.