Chlamydia trachomatis-infected macrophages induce apoptosis of activated T cells by secretion of tumor necrosis factor-? in vitro

• Published in: Medical microbiology and immunology 2004-02, Vol.193 (1), p.45-52
• Main Authors: Jendro, Michael C., Fingerle, Frederik, Deutsch, Tobias, Liese, Andrea, K hler, Lars, Kuipers, Jens G., Raum, Elke, Martin, Michael, Zeidler, Henning
• Format: Article
• Language: English
• Subjects: Bacteria; Cytokines; Immunoassay; Leukocytes; Microbiology; Sexually transmitted diseases; STD
• ISSN: 0300-8584; 1432-1831
• DOI: 10.1007/s00430-003-0182-1

Chlamydia trachomatis -infected macrophages induce T cell apoptosis. This ability might promote intracellular survival of Chlamydia and perpetuate chronic chlamydial infection. The purpose of this study was to examine the molecular mechanisms by which C. trachomatis -infected macrophages induce T cell apoptosis. Monocytes and T cells were isolated from the peripheral blood of healthy donors. Macrophages were infected with C. trachomatis, and autologous T cells were stimulated by mitogen. After 6 days, both populations were cultured together using a two-chamber transwell membrane system to differentiate between mechanisms involving either cell-to-cell contact or secretion of apoptotic factors. Apoptotic T cells were identified by propidium iodide through-flow cytometry, and tumor necrosis factor-alpha (TNF-alpha) concentrations were measured by enzyme-linked immunosorbent assay. Antagonists of TNF-alpha, the Fas (CD95) molecule, TNF-related apoptosis-inducing ligand (TRAIL), and catalase were added to differentiate between the pathways of apoptosis. C. trachomatis -infected macrophages significantly induced T cell apoptosis by cell-to-cell contact (mean +/- standard deviation, 30+/-4%; P