The prevalence of autoimmune disease can be attributed to toxins that damage the epithelial barrier, or the layer of cells and junctions that seal the space between epithelial cells, which can be found in the lungs, mouth, stomach, and skin, setting off a cycle of inflammation and barrier damage. Playing a major role in inflammation in autoimmune diseases such as allergies, asthma, and eczema, are Th2 cells. Overactivation of Th2 cells leads to production of IL-4, which stimulates Th2 production, increasing the effects of overproduction and inflammation and resulting in the symptoms of autoimmune disease.

Enterotoxins from S. aureus, a common human pathogen, known as SEs, can act as superantigens and activate T cells, generating an exacerbated immune response which can lead to increased risks of asthma and eczema. One superantigen, SEA, has been shown to be inhibited when added to apple juice, suggesting that phenolic compounds may be effective in inactivating SEA in vivo.

In order to combat an overactive immune response, a yeast, such as S. cerevisiae, can be engineered to produce SEA-inactivating phenolic compounds in order to reduce immune response and thus the symptoms of eczema.