Evaluation of Mycobacterial Antigens in an Enzyme-Linked Immunosorbent Assay (ELISA) for the Serodiagnosis of Tuberculosis

Abstract

Five mycobacterial antigens were compared in an ELISA for the serodiagnosis of tuberculosis. The antigens studied were an unheated sterile culture filtrate of Mycobacterium tuberculosis, tuberculin purified protein derivative (PPD) from M. tuberculosis (PPDa), purified cytoplasmic protein antigens 5 and 6 from M. tuberculosis and a PPD prepared from M. kansasii (PPDk). Multivariate analysis of variance showed that geometric mean titers obtained with each of the antigens in ELISA were significantly different in tuberculosis patients and in control groups. The covariation of the ELISA results with the 5 antigens was highly interdependent. Analysis of receiver operating characteristics revealed that the most accurate test was obtained with antigen 5; PPDa, M. tuberculosis antigen 6 and M. tuberculosis culture filtrate were, in descending order, less accurate.