Figure 1.

Protection from E. histolytica invasion by neutrophils activated by gut microbes at the early phase (A) and exacerbation of tissue damage by neutrophils excessively activated by E. histolytica secreted proteins at the later phase (B) of infection. (A) Neutrophils are continuously stimulated by host gut microbes in the resting state before infection (①). These neutrophils are potent in protecting host intestinal epithelial cells from E. histolytica invasion (②). (B) However, once E. histolytica invades the submucosa, neutrophils excessively activated by E. histolytica secreted proteins and host proinflammatory cytokines (①’) exacerbate tissue damage (②’).