The probiotic Escherichia coli strain Nissle 1917 induces γδ T cell apoptosis via caspase- and FasL-dependent pathways

• Published in: International immunology Vol. 20; no. 7; pp. 829 - 840
• Main Authors: Guzy, Claudia, Paclik, Daniela, Schirbel, Anja, Sonnenborn, Ulrich, Wiedenmann, Bertram, Sturm, Andreas
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.07.2008
• Subjects: caspases; Escherichia coli Nissle 1917; Fas ligand protein; inflammatory bowel diseases; γδ T cells; Fas ligand protein; γδ T cells; inflammatory bowel diseases; caspases; Nissle 1917
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/dxn041

Human γδ T cells play a vital role in the innate and adaptive immune response to microbial antigens by acting as antigen-presenting cells while at the same time being capable of directly activating CD4+ T cells. Pathogenic microbes or loss of tolerance toward the host′s own microflora trigger many diseases including inflammatory bowel diseases. We previously demonstrated that Escherichia coli Nissle 1917 directly interacts with the adaptive immune system by regulating central T cell functions. Here we aimed to investigate whether E. coli Nissle regulates γδ T cell function, thereby linking the innate and adaptive immune system. In our study, we demonstrate that, in contrast to the other probiotic strains tested, E. coli Nissle increased activation, cell cycling and expansion of γδ, but not αβ T cells. In γδ T cells, E. coli Nissle reduced tumor necrosis factor-α secretion but increased IL-6 and CXCL8 release. However, after activation, only E. coli Nissle induced γδ T cell apoptosis, mediated via Toll-like receptor-2 by caspase- and FasLigand-dependent pathways. γδ T cells play an important role in the recognition of microbial antigens and the perpetuation of inflammatory processes. The demonstration that E. coli Nissle, but not the other bacteria tested, profoundly regulate γδ T cell function contributes to explaining the biological function of this probiotic strain in inflammatory diseases and provides us with a better understanding of the role of γδ T cells.