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Strains of Mycobacterium bovis, M. bovis BCG, and M. tuberculosis, including a so-called Canetti strain, were analyzed by means of two-dimensional immunoelectrophoresis (2D-IE), 2D-IE combined with enzyme staining, and multilocus enzyme electrophoresis (MEE). The results demonstrated a close antigenic and enzymatic resemblance among all the strains tested, even though the BCG strains could be divided into two groups based on the presence of one precipitinogen. Eight of the precipitinogens were shown to correspond to enzymes in M. bovis BCG and 10 in M. tuberculosis. Thus, catalase, isocitrate dehydrogenase, malate dehydrogenase, peroxidase, and several others were identified. By means of MEE the strains of M. tuberculosis, M. bovis, and M. bovis BCG could be differentiated. The analyses further indicated that the M. tuberculosis strain Canetti was more closely related to M. bovis than to M. tuberculosis.

Selective staining procedures for four different enzymes (malate dehydrogenase, glutamic oxaloacetic transaminase, leucine aminopeptidase and glucose phosphate isomerase) in combination with two-dimensional immunoelectrophoresis were successfully applied to the analysis of antigen preparations from mycobacteria. Thus, a precipitate corresponding to malate dehydrogenase could e.g. be demonstrated in multi-linear precipitation patterns of Mycobacterium avium, Mycobacterium bovis BCG, Mycobacterium intracellulare, Mycobacterium kansasii, Mycobacterium marinum and Mycobacterium phlei. The analytical approach described can be advantageously used for identification of mycobacterial precipitinogens of enzyme character.

Two methods for detecting the phenolic glycolipid, PGL-1, a Mycobacterium leprae-specific molecule, in the urine of leprosy patients are described. Both methods rely on the 100-fold preconcentration of the urine, which can be accomplished by a single-step ultrafiltration procedure. The equivalent of approximately 2.5 micrograms of PGL-1/ml was detected in the urine of LL patients with an inhibition ELISA. The second method, a direct dot-blot assay on nitrocellulose paper, was much simpler and more sensitive. As little as 3 ng of antigen was detected by the dot-blot technique. PGL-1 was detected in the urine of LL patients.