In vitro Anti‐human Immunodeficiency Virus Type 1 Activity of Biliverdin, a Bile Pigment

Biliverdin (BY) is a bile pigment having anti‐allergic properties. We examined the effect of BV on human immunodeficiency virus type 1 (HIV‐1) in vitro. BV completely inhibited the cytopathic effect of HIV‐1 in MT‐4 cells at concentrations of 22.2 μg/ml or more. This inhibitory effect was also observed when BV was present during the adsorption period of HIV‐1. However, BV was cytotoxic to MT‐4 cells at concentrations above 800 μg/ml. At a concentration of 66.7 μg/ml, BV completely inhibited syncytia formation by HIV‐infected and uninfected MOLT‐4 cells. Moreover, after exposure of HIV‐1 particles to BV for 2 h, the infectivity of the virus was reduced in a dose‐dependent manner. It is speculated that the anti‐HIV activity of BV is due to direct inactivation of virions and inhibition of virus binding to target cells.