There is a lot of research that is being conducted on the microbiome-immune system connection. The hypothesis is that changes in the gut microbiota can influence immune system function. It is still unclear how this interaction works, but researchers are starting to get a better understanding of the pathways involved.
A recent study looked at how the gut microbiome influences T cells, which are important for immunity. The study found that the gut microbiota can affect T cell activation and proliferation. Another study showed that mice without a gut microbiome were more susceptible to infection than mice with a normal microbiome.
It is still unknown exactly how the gut microbiome influences immune system function, but it is clear that there is a connection. Further research is needed to determine the role of the gut microbiome in immunity and disease prevention.