Occurrence of an antigenic triacyl trehalose in clinical isolates and reference strains of Mycobacterium tuberculosis

A careful re-examination of the glycolipid content of clinical isolates and reference strains of the tubercle bacillus, Mycobacterium tuberculosis</it>, led to the identification of a glycoconjugate that passed unnoticed in earlier studies. Nuclear magnetic resonance spectroscopy, gas chromatography-mass spectrometry and chemical degradations were used to identify the glycolipid as a 2,3,6-triacyl trehalose. The glycolipid contains a phthienoic acyl substituent, a family of multimethyl-branched, α,β-unsaturated fatty acids specific for virulent strains of the tubercle bacillus. It reacted with sera from tuberculosis patients with a specificity and sensitivity of 96.2% and 76%, respectively. Comparable data were obtained with the 2,3-diacyl trehaloses of M. tuberculosis</it> and M. fortuitum</it> and with the triacyl trehaloses of M. fortuitum,</it> suggesting that the antigens from the latter species may be used for the serodiagnosis of tuberculosis.