title: Clinical value of specific detection of immune complex-bound antibodies in pulmonary tuberculosis.
abstract: Two actively secreted (38 and 30 kDa) and 1 cytosolic (16 kDa) antigens were purified from Mycobacterium tuberculosis culture filtrate and cytosol, respectively, using a combination of chromatographic and electrophoretic methods. One recombinant antigen (27 kDa) overexpressed in Escherichia coli was also isolated. The diagnostic test characteristics of circulating immune complex (CIC)-bound antibodies to purified protein antigens, singly and in combination, were evaluated in patients with pulmonary tuberculosis. The individual antigens ranged in their sensitivity from 73% to 88%, while considering the IgG response. Addition of IgA results improved the sensitivity. The combination of IgG results for 38, 30, and 16 kDa offered >95% sensitivity and specificity for the smear- and culture-positive tuberculosis, as well as for the smear-negative, culture-positive group. CIC-bound antibodies promise to be a better diagnostic tool than serum antibodies.
authors.affiliation: Department of Immunology, Tuberculosis Research Centre (ICMR), Chennai-600 031, India. alamelur@icmr.org.in
authors.forename: Alamelu
authors.initials: A
authors.lastname: Raja
authors.forename: Uma Devi
authors.initials: UD
authors.lastname: Ranganathan
authors.forename: Bethunaicken
authors.initials: B
authors.lastname: Ramalingam
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000936:Antigen-Antibody Complex / Q000097:blood*; D000942:Antigens, Bacterial; D004797:Enzyme-Linked Immunosorbent Assay; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012680:Sensitivity and Specificity; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial