Domains 1 and 2 of ICAM-1 are sufficient to bind human rhinoviruses

The intercellular adhesion molecule-1 (ICAM-1) receptor was expressed in primary chicken embryo cells using a retroviral vector and shown to specifically bind major group human rhinoviruses (HRVs). A truncated, membrane-bound ICAM-1 protein containing N-terminal domains 1, 2, and 3 retained the ability to bind virus whereas proteins containing domains 1 and 2 or domain 1 were not expressed under these conditions. Soluble forms of ICAM-1 proteins were expressed to circumvent the reduced expression levels of shorter ICAM-1 truncations. Full-length and truncated ICAM-1 molecules containing only domains 1 and 2 were capable of neutralizing HRV binding to cells. Soluble receptors containing only domain 1 could not be recovered. Mutants of ICAM-1 lacking carbohydrate attachment sites were constructed and shown to have no effect on the ability of ICAM-1 to bind HRVs. In addition, ICAM-1 proteins expressed in the presence of tunicamycin also retained their virus binding capability. These data suggest that the N-terminal two domains of ICAM-1 are sufficient for virus interaction and that carbohydrates do not play a major role in virus binding.