A cocktail of affinity-purified antibodies reactive with diagnostically useful mycobacterial antigens ES-31, ES-43, and EST-6 for detecting the presence of Mycobacterium tuberculosis.
A cocktail of affinity-purified antibodies against diagnostically useful Mycobacterium tuberculosis H37Ra excretory-secretory protein antigens ES-31, ES-43, and EST-6 was explored for detection of circulating free and immune-complexed (IC) antigen in sera of patients with confirmed tuberculosis (TB) by sandwich enzyme-linked immunosorbent assay and compared with monospecific anti-ES-31 antibody. Out of 68 smear-positive TB cases studied, using cocktail antibody, a sensitivity of 97% (66/68) for immune-complexed cocktail antigen and 91% (62/68) for free cocktail-antigen detection was observed, compared to 91% (62/68) for immune-complexed ES-31 and 79% (54/68) for free ES-31 antigen when anti-ES-31 antibody was used alone. Thus, combinatorial use of antibodies showed improved sensitivity and was thus observed to be better than single antibody. The specificity was observed to be 99% for immune-complexed antigen using cocktail antibody. Furthermore, analysis of different groups of TB sera showed that circulating immune-complexed antigen is a sensitive marker than free antigen.
Jamnalal Bajaj Tropical Disease Research Centre, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, Maharashtra 442102, India. jbtdrc_wda@sancharnet.in
Bhaskar Chinnaiah
BC
Harinath
Satish
S
Kumar
Santa Saha
SS
Roy
Suvarna
S
Hirudkar
Vijay
V
Upadhye
Niraj
N
Shende
D000907:Antibodies, Bacterial / Q000276:immunology* / Q000302:isolation & purification; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex / Q000032:analysis; D000942:Antigens, Bacterial / Q000097:blood*; D002846:Chromatography, Affinity; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013183:Sputum / Q000166:cytology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
D000907:Antibodies, Bacterial; D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial