Electron Microscopic Observations of Lipid Antigens

With Special Reference to the Wassermann Antigen

Abstract

The Wassermann antigen is a lipid micelle, and the essential component of the hapten is cardiolipin. It requires the addition of lecithin and cholesterol as auxiliary lipids. We conducted a study on the role of auxiliary lipids in the formation of the micelle structure using negative staining and observing with the electron microscope. The following results were obtained: (1) Cardiolipin, when dispersed in Mg-NaCl solution, presented an irregular network structure. Lecithin, on the other hand, revealed a regular lamellar structure. Cholesterol, since it is nonpolar, immediately agglutinated and precipitated when suspended in the aqueous system. (2) A combination of cardiolipin and lecithin presented a regular lamellar structure, but no network structure of eardiolipin was observed in the visible field. The combination of cardiolipin and cholesterol revealed eardiolipin surrounding structureless cholesterol with its network structure. The combination of lecithin and cholesterol exhibited a lamellar structure surrounding the cholesterol. (3) A combination of all three revealed a variegated picture of a lamellar structure formed by cardiolipin and lecithin surrounding the cholesterol as a core or of onionskin-like micelles attached to the above structure.