Purification of a Lipid Material (‘Cord Factor’) obtained from Young Cultures of Tubercle Bacilli

Abstract

WHEN young cultures of wet tubercle bacilli are mildly extracted with petroleum ether, a small quantity of a lipid material (‘cord factor’) is obtained¹. The most characteristic biological property of this material is a delayed type of toxicity. Mice injected at three- to four-day intervals with 0.1 mgm. of the crude extract die after ten to fourteen days, severely emaciated and with hæorrhages of the lungs. The crude material gives negative reactions for phosphorus² (sensitivity < 0.1 per cent phosphorus) and for nitrogen³ (sensitivity < 0.4 per cent nitrogen).