CLDN4 and infection: In immunocytochemistry, expression of G, F and M2-1 proteins after infection with RSV was markedly inhibited from 5 μg/ml curcumin, whereas upregulation of claudin-4 and occludin at the membranes after infection with RSV was inhibited by 10 μg/ml curcumin (Figure 3C and 4A).