Serological activity against a purified phenolic
glycolipid from Mycobacterium leprae, which may be obtained in large amounts from M. leprae infected armadillo liver, was investigated using immunodiffusion and an
enzyme linked
immunosorbent assay (ELISA). Generally a good correlation was obtained between these techniques, but the ELISA was more sensitive and convenient. Relatively high
IgG and
IgM anti-
glycolipid antibody levels were found in
lepromatous leprosy patients. The antibody titres to the
glycolipid were, however, low when compared with antibody titres to crude sonicates. Since the
glycolipid is present in large quantities, this suggests that it is not very immunogenic. Antibody against the
glycolipid especially of the
IgM class, was demonstrable in some
tuberculoid leprosy patients, although at much lower titres than in the
lepromatous leprosy sera. In
lepromatous leprosy patients that were skin smear negative after more than 5 years of treatment the
IgG anti-M. leprae derived
glycolipid activity had decreased markedly. The
anti-IgG and
IgM glycolipid antibody levels in
tuberculosis patients did not differ significantly from the levels in appropriate normal healthy subjects. The
glycolipid antibody levels in patients infected with M. kansasii, M. avium or M. intracellulare also fell within the range of normal healthy individuals.