ADRB2 and infection: Similarly, compared to the control group without infection, alpha-smooth-muscle actin (α-SMA), which is an indicator of fibroblast activity, increased in both Adrb2+/+ and Adrb2−/− mice infected with C. sinensis. However, the β2-AR-deficient mice infected by C. sinensis showed a significant decrease in α-SMA expression compared to the Adrb2+/+ infected group (Figure 3B, P<0.001).