The circadian clock of CD8 T cells modulates their early response to vaccination and the rhythmicity of related signaling pathways

Sep 19, 2019Proceedings of the National Academy of Sciences of the United States of America

The internal clock of CD8 T cells influences their early response to vaccination and the timing of related signaling pathways

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Abstract

Vaccination with dendritic cells presenting the OVApeptide antigen leads to a higher expansion of OVA-specific CD8 T cells when administered in the middle of the day.

Circadian rhythms influence the immune response, particularly in CD8 T cells.
The activation and proliferation of CD8 T cells are enhanced during daytime vaccinations.
A deficiency in the clock gene in dendritic cells reduces T cell response variations based on time of day.
Higher levels of T cell activation markers and related signaling pathways are observed three days after daytime vaccination.
A more effective response to bacterial challenges is seen when vaccinations occur during the day.

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Circadian variations of various aspects of the immune system have been described. However, the circadian control of T cells has been relatively unexplored. Here, we investigated the role of circadian clocks in regulating CD8 T cell response to antigen presentation by dendritic cells (DCs). The in vivo CD8 T cell response following vaccination with DCs loaded with the OVApeptide antigen (DC-OVA) leads to a higher expansion of OVA-specific T cells in response to vaccination done in the middle of the day, compared to other time points. This rhythm was dampened when DCs deficient for the essential clock genewere used and abolished in mice with a CD8 T cell-specificdeletion. Thus, we assessed the circadian transcriptome of CD8 T cells and found an enrichment in the daytime of genes and pathways involved in T cell activation. Based on this, we investigated early T cell activation events. Three days postvaccination, we found higher T cell activation markers and related signaling pathways (including IRF4, mTOR, and AKT) after a vaccination done during the middle of the day compared to the middle of the night. Finally, the functional impact of the stronger daytime response was shown by a more efficient response to a bacterial challenge at this time of day. Altogether, these results suggest that the clock of CD8 T cells modulates the response to vaccination by shaping the transcriptional program of these cells and making them more prone to strong and efficient activation and proliferation according to the time of day. 257-264Bmal1Bmal1

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The circadian clock of CD8 T cells modulates their early response to vaccination and the rhythmicity of related signaling pathways

Abstract

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