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Characterization of a 10- to 14-kilodalton protease-sensitive mycobacterium tuberculosis H37Ra antigen that stimulates human -yi T cells

Boom, WH and Balaji, KN and Nayak, R and Tsukaguchi, K (1994) Characterization of a 10- to 14-kilodalton protease-sensitive mycobacterium tuberculosis H37Ra antigen that stimulates human -yi T cells. In: Infection and Immunity, 62 (12). 5511 -5518 .

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gamma delta T-cell receptor-bearing T cells (gamma delta T cells) are readily activated by intracellular bacterial pathogens such as Mycobacterium tuberculosis. The bacterial antigens responsible for gamma delta T-cell activation remain poorly characterized. We have found that heat treatment of live M. tuberculosis bacilli released into the supernatant an antigen which stimulated human gamma delta T cells, gamma delta T-cell activation was measured by determining the increase in percentage of gamma delta T cells by flow cytometry in peripheral blood mononuclear cells stimulated with antigen and by proliferation of gamma delta T-cell lines with monocytes as antigen-presenting cells. Supernatant from heat-treated M. tuberculosis was fractionated by fast-performance liquid chromatography (FPLC) on a Superose 12 column. Maximal gamma delta T-cell activation was measured for a fraction of 10 to 14 kDa. Separation of the supernatant by preparative isoelectric focusing demonstrated peak activity at a pi of <4.0. On two-dimensional gel electrophoresis, the 10- to 14-kDa FPLC fraction contained at least seven distinct molecules, of which two had a pi of <4.5. Protease treatment reduced the bioactivity of the 10- to 14-kDa FPLC fraction for both resting and activated gamma delta T cells. Murine antibodies raised to the 10- to 14-kDa fraction reacted by enzyme-linked immunosorbent assay with antigens of 10 to 14 kDa in lysate of M. tuberculosis. In addition, gamma delta T cells proliferated in response to an antigen of 10 to 14 kDa present in M. tuberculosis lysate. gamma delta T-cell-stimulating antigen was not found in culture filtrate of M. tuberculosis but was associated,vith the bacterial pellet and lysate of M. tuberculosis. These results provide a preliminary characterization of a 10- to 14-kDa, cell-associated, heat-stable, low-pI protein antigen of M. tuberculosis which is a major stimulus for human gamma delta T cells.

Item Type: Journal Article
Publication: Infection and Immunity
Publisher: American Society for Microbiology
Additional Information: Copyright of this article belongs to American Society for Microbiology.
Department/Centre: Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited: 25 Mar 2011 05:19
Last Modified: 25 Mar 2011 05:20
URI: http://eprints.iisc.ac.in/id/eprint/36277

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