02714nas a2200337 4500000000100000008004100001260001300042653002600055653002400081653001800105653003800123653001600161653001100177653001200188653002600200653002100226653002500247653002500272653003200297653001100329100001400340700001200354700001200366700002000378700002000398245011500418300001000533490000700543520181200550022001402362 2006 d c2006 Oct10aAntibodies, Bacterial10aAntigens, Bacterial10aB-Lymphocytes10aEnzyme-Linked Immunosorbent Assay10aGlycolipids10aHumans10aleprosy10aLymphocyte Activation10aMolecular Weight10aMycobacterium leprae10aRecombinant Proteins10aSensitivity and Specificity10aSerine1 aParkash O1 aKumar A1 aNigam A1 aFranken K L M C1 aOttenhoff T H M00aEvaluation of recombinant serine-rich 45-kDa antigen (ML0411) for detection of antibodies in leprosy patients. a450-50 v643 a

The potential of the recombinant serine-rich 45-kDa antigen (ML0411) of Mycobacterium leprae to aid in detecting M. leprae-specific serum antibodies was assessed by an enzyme-linked immunosorbent assay (ELISA) in leprosy patients and controls comprising of tuberculosis patients, other unrelated skin-diseased patients and healthy individuals from India. All 18 multibacillary (MB) and 18/38 (47.4%) of the paucibacillary (PB) leprosy patients were found positive. None of the controls was positive, yielding complete (0/49) specificity in the series tested here. On the other hand, an anti-phenolic glycolipid-1 (PGL-I) antibody-detecting assay yielded detectable responses in 94.4% (17/18) of MB and 36.8% (14/38) of PB leprosy patients. Only two of 49 (4.1%) controls were positive, giving a specificity of 95.9%. Further, there was a good concordance (agreement of 83.8%; chi(2) = 40.3, P < 0.001; kappa = 0.63) between the two assays. Thus, the 45-kDa-based assay was slightly better than anti-PGL-I antibody-detecting assay. Interestingly, when combining the results of both the assays together for all leprosy patients (MB + PB), the combined sensitivity was significantly higher than that of the anti-PGL-I antibody-detecting ELISA alone (73.2% versus 55.4%; P < 0.05), but not (P > 0.05) compared with the 45-kDa antigen-based assay alone. Similarly, in case of PB patients, using both assays in combination, the sensitivity was significantly higher compared with anti-PGL-I antibody-detecting assay alone (60.5% versus 36.8%; P < 0.05). While adopting the combinatorial approach, the specificity remained invariably high (>95%). In conclusion, the results of the present study indicate that the M. leprae 45-kDa protein is a potent B-cell antigen and may be a useful serodiagnostic reagent.

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