Serological, nephelometrical, and statistical studies on the employment of synthetic lecithin in cardiolipin antigens.

Cardiolipin antigens, used in the sero-diagnosis of syphilis, are mixtures of the phospholipids, cardiolipin, and purified natural lecithin (beefheart or egg), and usually also contain cholesterol. In 1949 Baer and Kates (1949, 1950) succeeded in the synthesis of L-ac-dimyristoyl lecithin and in the following years other types of synthetic lecithin were produced, including a D-oc-dimyristoyl lecithin (Baer, 1952; Baer and Martin, 1951 ; Baer and Maurukas, 1952). The new substances were serologically evaluated by Rosenberg (1949), Kline (1950), Faure and Marechal (1952), and Tonks and Allen (1953), who all reported that the synthetic products were usable in the preparation of cardiolipin antigens, that is, for the VDRL microflocculation test, the Hinton, Rein-Bossak, and Kline microflocculation tests, and the Kolmer and Debain complement-fixation tests. Yet the antigens containing synthetic lecithin were generally weaker than antigens prepared with natural lecithin (Faure and Marechal, 1952). Land D-lecithins were found equally active (Tonks and Allen, 1953).