Cord factor (trehalose-6-6'-dimycolate) of in vivo-derived Mycobacterium lepraemurium.

Harvests of Mycobacterium lepraemurium obtained from livers of moribund infected mice yielded M. lepraemurium cell walls that were extracted with solvent to provide crude M. lepraemurium cell wall lipids. By solvent fractionation and chromatography on DEAE cellulose and cellulose, a cord factor-like glycolipids contaminated with mycoside C was obtained. Additional solvent treatment provided the purified glycolipid, which was identified as 6,6'-trehalose dimycolate, by infrared and chromatographic comparison with authentic samples from M. tuberculosis, by identification of trehalose and specific mycolates of M. lepraemurium, and by permethylation analysis. This constitutes the first unequivocal identification of cord factor as a product of in vivo-derived mycobacteria.