SYNTHETIC L-oc-DIOLEYL LECITHIN IN ANTIGENS FOR THE SERO-DIAGNOSIS OF SYPHILIS: COMPARISON WITH OTHER LECITHINS*t

The lecithin which is used in cardiolipin antigens for the sero-diagnosis of syphilis is extracted from beef heart tissue or egg yolk by the methods of Pangborn, Maltaner, Tompkins, Beecher, Thompson, and Flynn (1951). The product is actually a mixture of individual lecithins containing chiefly unsaturated but also some saturated fatty acids, the composition varying with the source and method of isolation. It is necessary, therefore, to control the preparation of the lecithin very carefully. Even so, its concentration in an antigen may have to be changed slightly from one lot to the next, necessitating careful standardization of the antigen. Because of these disadvantages, we have been testing various pure lecithins as substitutes for Pangborn lecithin in antigens for the Kolmer complement-fixation test and the VDRL microflocculation test. They include saturated L-a-(dimyristoyl)-lecithin, synthesized by Baer and his associates (Baer, 1953; Baer and Kates, 1950; Baer and Maurukas, 1952), and the unsaturated La-(dipalmitoleyl)-lecithin extracted from yeast by Hanahan and Jayko (1952), both of which have shown definite promise as antigen components (Tonks and Allen, 1953, 1955). The latest pure lecithin to be studied is unsaturated L-oc-(dioleyl)-lecithin, which was synthesized for the first time by Baer, Buchnea, and Newcombe (1956).t Samples were obtained from Dr. Baer and were tested in antigens prepared for the Kolmer and VDRL tests. The antigens were found to be reactive. Since this synthetic material is stable and can be measured by weighing, and since it is an