How Our Body Clock Influences Vaccine Responses

Research has shed insights into the mechanism behind how our circadian 24-hour body clock impacts our immune response to vaccines.

It had been previously found that humans mount a greater response to certain vaccines depending on the time of day at which the vaccine is administered; however the reason behind this wasn’t clearly understood. The variations in the structure of mitochondria influence how well dendritic cells function throughout the day.

Vaccine Response Influenced by Circadian Rhythm

Research author Professor Annie Curtis, 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 highlights the importance of circadian rhythms in immunity. We can apply this understanding in vaccine development to ensure we receive the maximum benefits from vaccination.”

The circadian clock within dendritic cells is controlling whether mitochondria form one of two shapes either long strings, ‘networked’, or broken into small punctate pieces. It is within the networked formation that vaccination is most effective as dendritic cells have a better ability break up the vaccine into small pieces for interaction with our immune cells (T cells). Within the study, researchers used an approach to induce the networked phase which could have implications in vaccine design allowing us to optimise our immune response, irrespective of time of day.