STUDIES ON THE CHEMISTRY OF THE CORD FACTOR OF MYCOBACTERIUM TUBERCULOSIS

Abstract

A lipide component of the tubercle bacillus, which was termed "cord factor" (l-4), has been described in previous publications.This bacterial constituent is characterized by its exclusive occurrence in strains of Mycobacterium tuberculosis which have the ability to multiply in vivo, by a particular delayed toxicity for mice upon repeated injections of small amounts (2.5 to 5 y of pure preparations), and by a definite r81e it plays in the virulence of the tubercle bacillus (5).The present paper describes methods for obtaining highly purified preparations of cord factor, and it shows that cord factor is present in different virulent strains of M. tuberculosis of both the human and the bovine type.It presents a partial structural analysis of cord factor, showing that the compound is an ester of mycolic acid containing 1 molecule of glucose, the latter being attached through a glucoside linkage to an as yet unidentified aliphatic fragment.A detailed description of the biological properties of the cord factor will be reported elsewhere (6).Anderson's pioneer work on mycobacterial lipides has made use of solvent fractionation methods (7), and fractionation by chromatography has been profitably introduced in this field by Asselineau and Lederer (8).The present workers have benefited from both these methods and, in addition, made extensive use of infra-red spectroscopy' as an aid in the identification of microquantities of lipides.The combined application of the three methods proved to be an excellent tool in the isolation and structural analysis of high molecular lipides of this class.EXPERIMENTAL Isolation and I'uriJication of Cord Factor from Various Strains of Virulent Tuber& Bacilli Bacteria-Tho bacilli wcrc grown as surface cultnrcs on a modified I,ocAkrmann medium (9) and harvested aft,er about 3 weeks as described CORD FACTOR OF M. TUBERCULOSIS