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Significance of bystander T cell activation in microbial infection

Nature Immunology volume 23, pages 13–22 (2022)Cite this article

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Abstract

During microbial infection, pre-existing memory CD8+ T cells that are not specific for the infecting pathogens can be activated by cytokines without cognate antigens, termed bystander activation. Studies in mouse models and human patients demonstrate bystander activation of memory CD8+ T cells, which exerts either protective or detrimental effects on the host, depending on the infection model or disease. Research has elucidated mechanisms underlying the bystander activation of CD8+ T cells in terms of the responsible cytokines and the effector mechanisms of bystander-activated CD8+ T cells. In this Review, we describe the history of research on bystander CD8+ T cell activation as well as evidence of bystander activation. We also discuss the mechanisms and immunopathological roles of bystander activation in various microbial infections.

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Fig. 1: Effector functions triggered by IL-15- or IL-12 plus IL-18-mediated bystander activation of memory CD8+ T cells.
Fig. 2: Bystander-activated memory CD8+ T cells contribute to liver damage during acute HAV infection.

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Acknowledgements

We thank J. E. Oh (KAIST) for critical discussion. This work was supported by the Samsung Science and Technology Foundation under project number SSTF-BA1402-51.

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  1. These authors contributed equally: Hoyoung Lee, Seongju Jeong.

Authors and Affiliations

  1. Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea

    Hoyoung Lee, Seongju Jeong & Eui-Cheol Shin

  2. The Center for Epidemic Preparedness, KAIST, Daejeon, Republic of Korea

    Eui-Cheol Shin

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  1. Hoyoung Lee
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Lee, H., Jeong, S. & Shin, EC. Significance of bystander T cell activation in microbial infection. Nat Immunol 23, 13–22 (2022). https://doi.org/10.1038/s41590-021-00985-3

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