Isolation of a Specific Antigen from the Triton X-100 Soluble Protein (TSP) Of Mycobacterium tuberculosis

ABSTRACT

Tremendous efforts have been made to develop better vaccines and diagnostic markers for the effective control of tuberculosis. Recently, we reported that the Triton X-100 soluble protein (TSP) of Mycobacterium tuberculosis induced strong T-cell proliferation and IFN-gamma production in humans, and also conferred a significant level of protection against tuberculosis in a mouse model. In this study, the TSP was prepared by Triton X-100 extraction of Mycobacterium tuberculosis bacilli, which was followed by Triton X-114 phase partitioning. Western blot analysis using sera of 177 active pulmonary tuberculosis patients and 323 healthy individuals revealed that the TSP contained a immunodominant 40-kDa antigen specifically reacting with some sera from pulmonary tuberculosis patients. The 40-kDa antigen was purified by ion-exchange chromatography, and partially characterized by two-dimensional gel electrophoresis and N-terminal sequencing. Results of this study suggest that 40-kDa molecule of the TSP antigen from the cell suface of Mycobacterium tuberculosis can be used as a serodiagnostic marker as well as a potential vaccine candidate against tuberculosis.