Immunodiagnosis of pulmonary tuberculosis by concomitant detection of antigen and antibodies of excretory-secretory protein of Mycobacterium tuberculosis H37Ra.
J Biosci
;
1998 Mar; 23(1): 19-23
Article
in English
| IMSEAR
| ID: sea-161173
ABSTRACT
With a view to diagnosing tuberculosis in populations in endemic areas, excretory-secretory antigen fraction (Mtb EST -6) of purified Mycobacterium tuberculosis H37Ra and affinity purified polyclonal antibodies against Mtb EST were used to detect both antibodies and circulating antigen in the sera of patients and disease-free individuals. Indirect stick penicillinase ELISA system using Mtb EST-6 detected antigen-specific IgG antibody in 84% of sputum positive, 77% of sputum negative pulmonary tuberculosis patients and 7% of healthy and 11% of subjects with nontub~rculosis diseases. Similarly, a sandwich penicillinase ELISA system using affinity purified anti Mtb EST antibodies detected circulating antigen in 83% and 61 % of sputum positive and negative pulmonary tuberculosis subjects. In contrast only 24% of healthy and 18% of disease controls showed seropositivity. Antibody assay showed higher sensitivity and specificity (83% and 91 % respectively) compared to antigen detection (sensitivity of 79% and specificity of 79%). However, by concomitant use of both assays it was possible to enhance the specificity of detection to 98%, though sensitivity was reduced marginally to 70%. The present study confirms the presence of both antigen and specific antibodies in the circulation during clinical disease and draws attention to the utility of Mtb EST -6 as a diagnostic marker of pulmonary tuberculosis
Full text:
Available
Index:
IMSEAR (South-East Asia)
Type of study:
Diagnostic study
Language:
English
Journal:
J Biosci
Year:
1998
Type:
Article
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