Comparing IL-33-KO mice with ST2-KO mice after GAS infection, we found that ST2-KO mice had fewer infiltrating cells and lower cell viability of infiltrating cells than those of IL-33-KO mice (Figure 3b,c), indicating that ST2 receptors expressed on cells played a decisive role in influencing the survival of infiltrating cells and cell migration at the beginning of infection. Here, IL33 is linked to infection.