Glycolipids of recent clinical isolates of Mycobacterium tuberculosis: chemical characterization and immunoreactivity.

Five distinct glycolipids were readily detected in isolates of Mycobacterium tuberculosis. Spectroscopic methods and chemical degradation techniques allowed the structural identification of four of these glycolipids. The specific phenolic glycolipid antigen previously characterized from the Canetti strain was found in all the strains examined, with identical structural features (triglycosyl phenol phthiocerol dimycocerosate). The other three glycolipids identified were acylated trehaloses: penta-acyl trehalose (containing phthienoyl substituents), tetra-acyl trehalose 2'-sulphate (with C40-C50 hydroxyphthioceranoyl substituents) and diacyl trehalose 2'-sulphate (with C16 and C18 substituents). The two latter glycolipids as well as the phenolic glycolipid immunoreacted with whole-cell antiserum, indicating their surface location. The occurrence of these glycolipid antigens in recent clinical isolates suggests their possible utilization in the serodiagnosis of tuberculosis and the rapid identification of M. tuberculosis with specific antisera.