At the immune/microbiota interface size: popularity matters.  29 October 2026

Our immune system is shaped by its interaction with the microbiota. At the heart of this symbiosis, certain bacteria appear to play a more significant role than others. Bacteria that most imprint our immune system are those that: (i) interact strongly with our antibodies, (ii) are relatively abundant in our microbiota, and (iii) are found in most individuals. Considering these three parameters is crucial for defining imbalances at the immune-microbial interface, as illustrated by the example of multiple sclerosis, using the methodological approach described in this article.