In vitro Inhibitory Activity of Soluble ICAM-1 for the Numbered Serotypes of Human Rhinovirus

We studied the antirhinovirus activity of soluble intercellular adhesion molecule-1 (sICAM-1) against all 100 numbered human rhinovirus (HRV) serotypes in human embryonic lung fibroblast (HEL) cells. sICAM-1 inhibited replication of 88 of 90 HRVs belonging to the major receptor group with 50% effective concentrations (EC 50 ) ranging from 0.1 to 41.1 μg ml −1 (~0.002 to 0.8 μM). No inhibition at 100 μg ml −1 (~2 μM) was observed for HRV belonging to the minor receptor group, type 87, and two serotypes of the major receptor group (types 23 and 25). Yield reduction assays done with five HRV serotypes in human adenoid expiants found that sICAM-1 had concentration-dependent inhibitory effects that correlated closely with the activity observed in HEL cells ( r 2 = 0.99, P < 0.001).