Proliferation of distinct human T cell subsets in response to live, killed or soluble extracts of Mycobacterium tuberculosis and Myco. avium

Abstract

SUMMARYThe proliferative responses of distinct cell subsets from healthy, bacille Calmette-Guérin (BCG)-vaccinated blood donors were assessed after in vitro stimulation with live or UV-killed Mycobacterium tuberculosis and Myco. avium or with soluble extracts obtained from either mycobacterial species. Proliferation of cell subsets was evaluated by flow cytometric determination of 5-bromo-2 0 -deoxyuridine incorporation into DNA and simultaneous identification of surface phenotypic markers. In the presence of monocytes, the response to whole (live or killed) bacteria was characterized by a predominant proliferation of CD4 + ® ¯ + T cells and, to a lesser extent, of CD8 + ® ¯ + T cells. Proliferation of CD8 + ® ¯ + T cells was primarily elicited by live rather than killed bacilli (P < 0 . 05). Conversely, when soluble bacterial extracts were used as stimulators, a preferential proliferation of°± + T cells, expressing predominantly V°9 + and V±2 + T cell receptor chains, was recorded. Moreover, when monocytedepleted cell populations were directly cultured with live bacteria, a marked proportion of CD3 -CD16 + (natural killer (NK)) cells was detected among the responding cells. Although both ® ¯ ,°± and NK cells have been previously shown to react with mycobacteria in vitro, their relative contributions to the response have been difficult to assess. Using a flow cytometric technique which allows direct identification of proliferating cells within complex cell populations, our study demonstrates significant differences in the ability of various mycobacterial antigen preparations to elicit proliferation of distinct cell subsets.

Strain-Dependent Variation inMycobacterium bovisBCG-Induced Human T-Cell Activation and Gamma Interferon Production In Vitro

“…1, right). These data are concordant with numerous previous studies (8,10,19,23,24). The three BCG strains tested differed significantly in the percentage of activated CD25 ϩ T cells they elicited in vitro.…”

In Vitro Responsiveness of γδ T Cells fromMycobacterium bovis-Infected Cattle to Mycobacterial Antigens: Predominant Involvement of WC1+Cells

“…An increasing body of evidence has shown human and murine ␥␦ T cells responding to mycobacterial antigens (3,20,23,50,58), possibly displaying many of the effector functions described for ␣␤ T cells (32). The present investigation used a natural host disease model to study the responses of bovine ␥␦ T cells, in comparison with those of ␣␤ T cells, to mycobacterial antigens.…”

Comparative Analysis of T Lymphocytes Recovered from the Lungs of Mice Genetically Susceptible, Resistant, and Hyperresistant toMycobacterium tuberculosis-Triggered Disease

“…Two hours later, auxiliary lymph nodes were extracted, single-cell suspensions were prepared individually, and BrdU incorporation was assessed as described previously by Esin et al (27). Cells were washed in mouse tonicity HBSS supplemented with 5% FCS and 20 U/ml DNase I (Sigma).…”