PATHWAY OF RHINOVIRUS DISRUPTION BY SOLUBLE INTERCELLULAR-ADHESION MOLECULE-1 (ICAM-1) - AN INTERMEDIATE IN WHICH ICAM-1 IS BOUND AND RNA IS RELEASED

We have examined the pathway of rhinovirus interaction with soluble intercellular adhesion molecule 1 (sICAM-1). Binding of sICAM-1 to rhinovirus serotypes 3 and 14 gives particles with sedimentation coefficients from 145 to 120S, depending on the amount of sICAM-1 bound. The formation of 120S particles is faster and more extensive at a neutral pH than at an acidic pH. A large number of receptors (>30) can bind to human rhinovirus 3 without disruption. Disruption by sICAM-1 of rhinovirus that yields 80S particles is strongly temperature dependent and is antagonized by a low pH. Interestingly, sICAM-1 remains bound to the viral capsid after RNA is released, although in smaller amounts than those observed for the native virus. We have found heterogeneity both between and within 80S particle preparations in the VP4 content and number of bound receptors. The ability of the virus to remain bound to its receptor during the uncoating process may facilitate the transport of the viral genome into the cytoplasm in vivo.