The ability to induce several cytokines relevant to tuberculosis (TNF-a, IL-1b, IL-6, IL-12p40 and IL-23) by cord factor (trehalose dimycolate) from Mycobacterium alvei CR-21T andMycobacterium brumae CR-270 T was studied in the cell lines RAW 264.7 and THP-1, and compared to the ability of cord factor from Mycobacterium tuberculosis H37Rv, where this glycolipid appears to be implicated in the pathogenesis of tuberculosis. Details of the fine structure of these molecules were obtained by NMR and MS. The mycoloyl residues were identified as a and and IL-12p40 prevailed. The data obtained indicate that cord factors from the atypical mycobacteria M. alvei CR-21 T and M. brumae CR-270 T stimulated the secretion of several pro-inflammatory cytokines, although there were some differences with those of M. tuberculosis H37Rv. This finding seems to be due to their particular mycoloyl substituents and could be of interest when considering the potential adjuvanticity of these molecules.

The structure of cord factor was studied in several strains of Mycobacterium simiae, including 'habana' TMC 5135, considered as highly immunogenic in experimental tuberculosis and leprosy. The mycolic acids liberated from cord factor were identified in all cases as a9-, a-and ketomycolates. According to the general NMR and MS data, a9-mycolates were mono-unsaturated and contained from 64 to 68 carbon atoms, whereas a-mycolates mainly presented two 2,3-disubstituted cyclopropane rings and a chain length of 80-91 carbon atoms; keto-mycolates mostly contained one cyclopropane ring and 85-91 carbon atoms. Taking into account the 1 H-NMR results, strains varied in the ratio of the different mycolates, and the high levels of ketomycolates found in the cord factors of TMC 5135 and ATCC 25275 T stood out. Notably, MS revealed that the odd carbon number series of a-mycolates (C87-C89) predominated in the cord factor of TMC 5135, in contrast to the remaining studied strains, in which the even (C84-C86) and odd carbon number series appeared more equal. The fine structural differences detected among the cord factors studied did not seem to be relevant to the general capacity of these molecules to induce the secretion of tumour necrosis factor alpha, as the cord factors from several strains of M. simiae (TMC 5135, IPK-342 and ATCC 25275 T ) induced similar amounts of this cytokine in RAW 264.7 cells.