Antibodies to Mycobacterium tuberculosis in leprosy

Humoral immunity in Hansen's disease

For many years immune response in leprosy has been studied. Since 1960 several reports dealing with humoral immunity have been described in the literature. Different autoantibody rates occur in leprosy. There is an increase in the prevalence of autoantibodies in elderly patients with long standing disease, in lepromatous leprosy and in those with reactional states. The differences in rates among various studies are attributed to different methods and variations among patient samples concerning age, gender, polar forms, therapy and other elements. The prevalence of numerous antibodies, immune complexes, cryoglobulins and complement levels have been studied by many authors. This also highlights the importance of the more recent reviews of anti-Mycobacterium leprae glycolipid antibodies such as the anti-phenolic glycolipid-I antibodies in which titers are variable and depend on genetic factors.

Immunological evaluation of a 12-kilodalton protein of Mycobacterium tuberculosis by enzyme-linked immunosorbent assay

OBJECTIVE

To purify and study the seroreactivity of native and recombinant 12-kilodalton protein of Mycobacterium tuberculosis H37Rv.

DESIGN

M. tuberculosis H37Rv cells and Escherichia coli XL-1 containing the plasmid PRL4 encoding the M. tuberculosis heat shock protein GroES homolog were used as sources for the purification of native and recombinant 12 kD of M. tuberculosis respectively. The seroreactivity of the 12 kDs was studied by ELISA using sera from 35 leprosy and 25 active pulmonary tuberculosis (TB) patients, and from 10 normal healthy controls.

RESULTS

The 12 kD protein was purified from H37Rv extract (s12 kD) and from recombinant E. coli (r12 kD) by ultrafiltration and MonoQ fast pressure liquid chromatography (FPLC). Analysis of s12 kD and r12 kD by SDS-PAGE revealed a single protein band in both cases with an approximate molecular weight of 12,000 which was recognized by monoclonal antibody SA-12 in immunoblotting. Both the proteins exhibited a pI of approximately 4.6 by isoelectric focusing. Both the 12 kD proteins exhibited 96% positivity with TB sera as compared to normal control sera (P < 0.01). Only one serum sample from the 35 leprosy sera tested exhibited binding to both the s12 kD and r12 kD proteins. Delayed type hypersensitivity reaction to the 12 kD proteins was elicited in guinea pigs that had been immunized with H37Rv sonicate.

CONCLUSION

The 12 kD protein could be easily purified and could serve as a valuable serodiagnostic tool in the screening of TB cases from a large population in an endemic area.

Enzyme-linked immunosorbent assay for distinguishing serological responses of lepromatous and tuberculoid leprosies to the 29/33-kilodalton doublet and 64-kilodalton antigens of Mycobacterium tuberculosis

Immunoblot assays for the antibodies to Mycobacterium tuberculosis sonic extracts showed that all serum specimens of 40 lepromatous and of 28 tuberculoid leprosy patients reacted in a significant manner to 29/33-kilodalton (kDa) doublet and 64-kDa antigens, respectively. By using an enzyme-linked immunosorbent assay, we observed a significantly high immunoglobulin G antibody titer to the purified M. tuberculosis 29/33-kDa doublet and 64-kDa antigens in lepromatous and tuberculoid leprosy patients, respectively, as compared with normal subjects and tuberculosis patients. This enzyme-linked immunosorbent assay serology may be useful for distinguishing two polar types of leprosy and for diagnosing leprosy in general.

Serological responses of patients with lepromatous and tuberculoid leprosy to 30-, 31-, and 32-kilodalton antigens of Mycobacterium tuberculosis

Sera from patients with lepromatous and tuberculoid leprosy were examined in immunoblot assays for antibodies to Mycobacterium tuberculosis culture filtrate antigens. Antibodies to 30- and 31-kilodalton proteins were present in 88 and 81%, respectively, of 16 patients with lepromatous disease and absent in 16 patients with tuberculoid disease. Antibodies to a 32-kilodalton protein were found in 12 and 38% of lepromatous and tuberculoid patients, respectively. These reactivities may be useful for distinguishing lepromatous and tuberculoid leprosy.