Research from the RCSI University of Medicine and Health Sciences has provided new insight into the mechanism behind how our 24-hour circadian body clock affects our immune response to vaccines depending on the time of day.
The paper published in nature communication studied the changes that take place in the mitochondria of a key immune cell involved in the vaccine response and could help improve the design and timing of administration of future vaccines to maximize efficacy.
It had previously been found that people responded more strongly to certain vaccines depending on the time of day the vaccine was given, but the reason for this was not entirely clear. This research revealed that our circadian clock changes the shape of mitochondria in dendritic cells. The variations in the structure of mitochondria affect how well dendritic cells function throughout the day.
Research author Professor Annie Curtis of the School of Pharmacy and Biomolecular Sciences at RCSI said: “Our discovery has shed light on a crucial aspect of our body’s response to vaccination and highlighted the importance of circadian rhythms in immunity. We can apply this understanding when developing vaccines to ensure we get the maximum benefit from vaccination.”
The circadian clock in dendritic cells controls whether mitochondria form one of two shapes, either long strands, “networked,” or broken into small point-like pieces. Within the networked formation, vaccination is most effective because dendritic cells are better able to break down the vaccine into small pieces to interact with our immune cells (T cells). As part of the study, researchers used an approach to induce the cross-linked phase, which could have implications for vaccine design and allows us to optimize our immune response regardless of the time of day.
The majority of this study was supported by funding provided by the Irish Research Council’s Science Foundation Ireland Career Development Award (CDA) program through a Laureate Award and an RCSI Strategic Academic Recruitment Program (StAR) award. Additional support came from a Conacyt grant, an SFI Investigator Award, and a European Research Council Consolidator Award.
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