Exposome and Immunity Training: How Pathogen Exposure Order Influences Innate Immune Cell Lineage Commitment and Function
Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
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Authors to whom correspondence should be addressed.
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Authors contributed equally to this work.
Int. J. Mol. Sci. 2020, 21(22), 8462; https://doi.org/10.3390/ijms21228462
Received: 2 October 2020 / Revised: 29 October 2020 / Accepted: 9 November 2020 / Published: 11 November 2020
(This article belongs to the Section Molecular Immunology)
Immune memory is a defining characteristic of adaptive immunity, but recent work has shown that the activation of innate immunity can also improve responsiveness in subsequent exposures. This has been coined “trained immunity” and diverges with the perception that the innate immune system is primitive, non-specific, and reacts to novel and recurrent antigen exposures similarly. The “exposome” is the cumulative exposures (diet, exercise, environmental exposure, vaccination, genetics, etc.) an individual has experienced and provides a mechanism for the establishment of immune training or immunotolerance. It is becoming increasingly clear that trained immunity constitutes a delicate balance between the dose, duration, and order of exposures. Upon innate stimuli, trained immunity or tolerance is shaped by epigenetic and metabolic changes that alter hematopoietic stem cell lineage commitment and responses to infection. Due to the immunomodulatory role of the exposome, understanding innate immune training is critical for understanding why some individuals exhibit protective phenotypes while closely related individuals may experience immunotolerant effects (e.g., the order of exposure can result in completely divergent immune responses). Research on the exposome and trained immunity may be leveraged to identify key factors for improving vaccination development, altering inflammatory disease development, and introducing potential new prophylactic treatments, especially for diseases such as COVID-19, which is currently a major health issue for the world. Furthermore, continued exposome research may prevent many deleterious effects caused by immunotolerance that frequently result in host morbidity or mortality.
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Keywords:
exposome; trained immunity; epigenetics; NK cells; monocytes; macrophages; dendritic cells; histone modification; DNA methylation; COVID-19; SARS-CoV-2
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MDPI and ACS Style
Adams, K.; Weber, K.S.; Johnson, S.M. Exposome and Immunity Training: How Pathogen Exposure Order Influences Innate Immune Cell Lineage Commitment and Function. Int. J. Mol. Sci. 2020, 21, 8462. https://doi.org/10.3390/ijms21228462
AMA Style
Adams K, Weber KS, Johnson SM. Exposome and Immunity Training: How Pathogen Exposure Order Influences Innate Immune Cell Lineage Commitment and Function. International Journal of Molecular Sciences. 2020; 21(22):8462. https://doi.org/10.3390/ijms21228462
Chicago/Turabian StyleAdams, Kevin; Weber, K. S.; Johnson, Steven M. 2020. "Exposome and Immunity Training: How Pathogen Exposure Order Influences Innate Immune Cell Lineage Commitment and Function" Int. J. Mol. Sci. 21, no. 22: 8462. https://doi.org/10.3390/ijms21228462
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