New body clock research could improve our response to vaccines

5 Dec 2022

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RCSI researchers found that our body clock changes the shape of mitochondria within certain cells, impacting our response to vaccines.

Irish researchers have new insights into how the human body clock influences our immune response to vaccines. The findings could help improve the design and timing of vaccines in the future to boost effectiveness.

Our body clock is a 24-hour cycle of circadian rhythms, which are various physical, mental and behavioural changes that respond to external changes such as light.

Previous studies have suggested that humans have a greater response to certain drugs and vaccines depending on the time of day they are administered. However, researchers at the RCSI University of Medicine and Health said the reasons behind this were not clearly understood.

In a new study published in the journal Nature Communications, the research team said that humans’ circadian clock changes the shape of mitochondria within dendritic cells – a type of immune cell that boosts immune responses.

The researchers said the variations in the mitochondria’s structure influence how well these dendritic cells function throughout the day.

Specifically, the RCSI team said the circadian clock controls whether mitochondria form either long “networked” strings, or are broken into small pieces.

They added that vaccination is most effective when the mitochondria is networked, as dendritic cells then have a better ability break up the vaccine into small pieces for interaction with the immune system’s T cells.

Research author Prof Annie Curtis said these findings could help improve vaccine development and the timing of vaccine administrations to maximise effectiveness.

“Our discovery has shed light on a crucial aspect of our body’s response to vaccination and highlights the importance of circadian rhythms in immunity,” Curtis added.

In the study, the researchers also used an approach to induce the networked phase within mitochondria, which could make it easier to optimise our immune response to vaccines, regardless of the time of day.

Funding from the study primarily came from a Science Foundation Ireland (SFI) career development award, an Irish Research Council laureate award and an RCSI strategic academic recruitment award. Further support was provided by a Conacyt grant, a SFI investigator award and a European Research Council consolidator award.

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Leigh Mc Gowran is a journalist with Silicon Republic