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.