SCARB2 and viral infectious disease: Fig 8E and 8F showed that AL-18 could still exhibit antiviral effect, but LA-18 or AA-18 lost their ability to inhibit viral infection. Consistent with this, AL-18 could inhibit virus interaction with SCARB2, while LA-18 or AA-18 could not (Fig 8G). These results suggest that the 20th residue of LL-18 was the most important residue for its antiviral activity and virus interaction.