Further characterization including preliminary chemical analysis of antigen MLW1 from Mycobacterium leprae.

MLW1, an antigen preparation from Mycobacterium leprae previously shown to have a high content of M. leprae antigen No. 7 (ML7), was found to contain the typical cell wall constituents arabinose, galactose and mannose. The fatty acid composition of MLW1 was largely comparable to that of undisrupted cells. The capacity of MLW1 to stimulate lymphocytes was further studied. Good correlation was obtained between the in vitro lymphocyte responses to MLW1 and human-derived M. leprae, indicating similar specificity of the two antigen preparations in this test. The stimulatory activity of MLW1 was not significantly influenced by batch to batch variations, was well-preserved during storage and most of it was heat-stable. Attempts to remove the ML7 antigen indicate that this component plays a dominant role in inducing in vitro lymphocyte stimulation.

Fatty acid and polar lipid analysis as tools in the identification of Mycobacterium leprae and some related slow-growing mycobacterial species.

Some species of slow-growing Mycobacteria, including Mycobacterium leprae (1 strain), M. lepraemurium (2 strains), M. paratuberculosis (12 strains) and a group of 12 M. avium-like strains (isolates from wild animals) were examined by gas chromatography (GC) for cellular fatty acids and by thin-layer chromatography (TLC) for polar lipids. All the GC patterns, including that of M. leprae, contained high levels of tuberculostearic-, stearic-, octadecenoic- and palmitic acid. Tetradecanoic-, pentadecanoic-, hexadecenoic- and heptadecanoic acid were also generally present but in lower concentrations. In addition to these acids shared by all strains, each bacterial species or group was found to exhibit compounds which were not detected (or detected in considerably lower quantities) in the other taxa examined. Thus each bacterial species or group could be distinguished by their GC profiles. The corresponding TLC patterns were also rather complex. A total of 39 different spots were distinguished. A few of these were shared by all strains, some were characteristic of certain species or groups, whereas others were strain-specific. Both M. leprae and M. lepraemurium shared several features with the other strains but could be distinguished from each other and from the others by their patterns of slow-moving (polar) spots. The 12 M. avium-like strains were divided into two main groups, one with only a few slow-moving spots (rough stains), and one with several slow-moving spots (smooth strains) which included the M. avium reference strains.