COMPARATIVE ANTIRHINOVIRAL ACTIVITIES OF SOLUBLE INTERCELLULAR-ADHESION MOLECULE-1 (SICAM-1) AND CHIMERIC ICAM-1 IMMUNOGLOBULIN-A MOLECULE

We conducted a comparative study of the antirhinovirus activities of s oluble intercellular adhesion molecule-1 (sICAM-1) and a chimeric ICAM -1/immunoglobulin A (IgA) molecule (IC1-5D/IgA) for nine major recepto r group human rhinovirus (HRV) serotypes and for a variant of HRV-39 r elatively resistant to inhibition by sICAM-1. IC1-5D/IgA inhibited the infectivity of eight of the nine wild-type HRVs and the resistant HRV -39 variant and was 60 to 170 times more potent than sICAM-1 on a mola r basis. In contrast to sICAM-1, IC1-5D/IgA directly neutralized the i nfectivity of the representative HRVs by similar to 1 log(10). These r esults expand on the antirhinovirus spectrum of IC1-5D/IgA, confirm th at dimeric forms of sICAM-1 have a higher antirhinoviral potency than monomeric sICAM-1, and indicate that cross-linking of two adjacent rec eptor binding sites on the virus capsid by a divalent receptor enhance s the direct inactivation of viral infectivity.