Isolation and partial characterisation of the Triton X-100 solubilised protein antigen from Mycobacterium tuberculosis

This report describes extraction of a new native antigen fraction from Myco bacterium tubevculosis without massive degradation of proteins by Triton X- 100. The Triton X-100 solubilised protein (TSP) antigen showed a characteri stic antigen profile and reproducible extraction pattern. To characterise t he nature of their composition, the TSP antigen was fractionated by Triton X-114 phase partitioning. The TSP antigen contained a variety of lipids and glycoconjugates as well as diverse proteins. Most proteins were partitione d into the aqueous phase during phase fractionation, whereas non-protein mo lecules and lipoproteins were recovered in the detergent phase. The lymphop roliferative responses to the TSP aqueous fraction in healthy tuberculin re actors were significantly higher than those to the purified protein derivat ive (PPD) and unfractionated TSP. In contrast, the antibody responses to TS P aqueous fraction in tuberculosis patients showed weak reactivity, This st udy suggests that the TSP aqueous fraction can be used as a T-cell antigen associated with protective immunity against tuberculosis.