Chemotherapeutic activity of clofazimine and its analogues against Mycobacterium tuberculosis. In vitro, intracellular, and in vivo studies.

Clofazimine (CFM), a riminophenazine drug, is primarily used in therapy for leprosy and Mycobacterium avium infections. With an objective of identifying drugs active against Mycobacterium tuberculosis, including those with multi-drug resistance, we investigated CFM and nine of its chemical analogues. Among these, B746 and B4101 had better activity than CFM against six drug-susceptible and nine single/multiple drug-resistant M. tuberculosis strains. B746 also showed slightly better activity than CFM against intracellular M. tuberculosis in J774A.1 macrophages and was comparable to CFM in its in vivo activity against experimental tuberculosis in C57BL/6 mice. Interestingly, it caused less pigmentation in internal organs.

Serology of tuberculosis. III. Crossed immunoelectrophoretic analysis of sera from tuberculosis and leprosy patients with antigens from BCG.

Sera from tuberculous and leprous patients have been examined for antibody reactivities against components of BCG sonicate (BCGS) antigen. A crossed immunoelectrophoresis with intermediate gel reference system was used in which more than 40 components of BCGS could be identified. Forty (74.1%) out of 54 tuberculous sera and 68 (90.7%) out of 75 leprous sera reacted with at least 1 component of BCGS. While tuberculous sera reacted with 9 distinct components of BCGS, leprous sera reacted with at least 12. Components of BCGS precipitated by tuberculous sera were not specific as they were also precipitated by leprous sera. Overall, non-specific antibody responses were found to be dominant among tuberculous sera and by comparison, the reactivity of leprous sera with BCGS components was of a higher magnitude. Among tuberculous sera, precipitating activity was maximal among those taken from chronic treated cases with relapse followed by those obtained from treated and untreated new cases. Some components of BCGS to which both tuberculous and leprous sera showed strong reactivity have been characterized. It is concluded that immunoprecipitation methods with BCG derived antigens are not useful for the detection of a specific antibody response in tuberculosis or for discrimination between tuberculosis and leprosy.

Serology of leprosy. II. Demonstration of specific antibodies to mycobacterium leprae by counter current electrophoresis.

A rapid and simple method for the demonstration of specific antibodies to Mycobacterium leprae using counter current electrophoresis (CCE) has been described. Three types of antigens (sonicate antigen, surface antigen and purified protoplasmic protein antigen) were prepared from purified M. leprae and tested against sera from patients with different types of leprosy, and their healthy household contacts, by CCE. Antibodies specific to M. leprae were demonstrated by CCE after absorption of sera with M tuberculosis and M. vaccae. All advanced forms of leprosy (LL and BL) and a lesser number of other forms of leprosy (BB, BT and TT) showed specific antibodies reactive with the three types of soluble antigens from M. leprae and antibodies reactive with soluble antigens from M. tuberculosis and M. vaccae. The latter type of antibodies were however removed by prior absorption of sera with respective mycobacteria. The applicability of the simple electrophoresis method in the serology of leprosy is discussed.

Serology of leprosy. I. Indirect hemagglutination test with stabilized sensitized red cells.

An indirect hemagglutination (IHA) test has been described for the qualitative and quantitative detection of antibodies specific to Mycobacterium leprae. Aldehyde stabilized red cells were sensitized with a sonicate antigen prepared from M. leprae purified from armadillo liver. These cells were titrated against sera from patients with different types of leprosy, their healthy household contacts and patients with tuberculosis. Specific antibodies were demonstrated in leprous sera by IHA test after absorption of sera with M. tuberculosis and M. vaccae. All advanced forms of leprosy (LL and BL) and a variable number of other forms of leprosy (BB, BT and TT) showed a positive result with an IHA titre of 1 in 32 or above. None of the household contact sera nor sera from tuberculosis patients showed a positive IHA test. The application of the simple hemagglutination test in the immunoepidemiology of leprosy is discussed.