Compared with the control group, HPS4-YC infection significantly decreased the TEER at 8, 12, 18 and 24 h after infection, and there was no significance at 4 h and 6 h post-infection of HPS4-YC (Figure 2C), indicating that HPS4-YC infection gradually reduced the TEER value. The gene discussed is HPS4; the disease is infection.