New antigen and antibody detection methods for serodiagnosis of human tuberculous

ABSTRACT

The present work aimed to develop enzyme linked immunosorbent assay [ELISA] for early diagnosis of pulmonary TB by detection of Mycobacterium tuberculosis [M. tuberculosis] antigen and/or antibody in serum of TB patients, contacts and healthy controls. The study was performed on 4 groups of subjects: Egyptian pulmonary TB patients [12], Egyptian contacts of TB patients [10], Egyptian normals [7] and Birmingham normals [5]. Sera from patients, contacts and controls were used for detection of M. tuberculosis antigen in serum immune complexes by sandwich ELISA using DEAE purified rabbit anti-M. tuberculosis H37 RV IgG antibody. Detection of antibodies in serum was done using purified recombinant M. tuberculosis superoxide dismutase [SOD]. By antigen capture ELISA 10 of the 12 Egyptian patients and one of each of the Egyptian contacts and controls tested proved positive. All Birmingham normals were negative. The antibody levels to mycobacterial SOD antigens in TB patients and controls showed a significant rise in level of antibodies in sera of pulmonary TB patients than in the healthy controls. This study indicated that, serodiagnosis by antigen detection in TB patients sera using DEAE purified rabbit anti-M. tuberculosis H37 RV IgG antibodies is reliable and could be used as an alternative test than sophisticated assays as DNA probes and PCR. Regarding the value of serodiagnosis by detection of anti-SOD antibodies, it seems to be a promising test but needs further evaluation