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Enzyme-linked Immunospot Assay (ELISPOT): Quantification of Th-1 Cellular Immune Responses Against Microbial Antigens
Published on: November 23, 2010
Performance of recombinant ESAT-6 antigen (ML0049) for detection of leprosy patients
1National JALMA Institute for Leprosy and other Mycobacterial Diseases, TajGanj, Agra, India. om1234@gmail.com
Aims:
The study was aimed to evaluate the Mycobacterium leprae recombinant early secreted antigenic target-6 (rESAT-6) for its serological performance in leprosy patients.
Methods And Results:
Employing enzyme-linked immunosorbent assay (ELISA), serum samples were tested for prevalence of immunoglobulin G antibodies against M. leprae rESAT-6. The results revealed that the sensitivity of the assay for smear-positive leprosy patients was 82.4% (14 of 17) while for smear-negative patients it was 19.4% (six of 31). Interestingly, the performance of ESAT-6-based assay was statistically comparable with anti-phenolic glycolipid-I antibody-detecting ELISA, a most widely studied serological assay in leprosy. Regarding specificity, none of the 48 controls was positive indicating that antibody response to ESAT-6 was highly specific. Moreover, a high concordance between bacterial index and anti-ESAT-6 antibody-detecting assay was noted.
Conclusions:
Recombinant ESAT-6 seems to be a potential serological reagent for detection of M. leprae infection.
Significance And Impact Of The Study:
ESAT-6 serology may have utility for (i) early diagnosis, particularly, of highly infectious form (multibacillary, MB) of leprosy, (ii) monitoring the response in smear-positive leprosy patients during the course of the chemotherapy, (iii) classification of leprosy patients into MB and paucibacillary groups for treatment purpose. Hence, further research on these lines is warranted.
