Figure 2.

The conceptual framework of Yin-Yang theory in gut mucosal immune equilibrium. The application of the Yin-Yang theory to the mucosal immune equilibrium in the gut can be explored from three perspectives: the interaction between the host immune system and the gut microbiota, the interplay of cells and molecules within the immune system itself, and the overall immune equilibrium of the host organism. In each perspective, a deeper understanding of the concept of immune equilibrium can be achieved through the lens of the four principles of the Yin-Yang theory. The cyclical operation of these Yin-Yang principles corresponds to the dynamic changes in immune equilibrium.