Cytoplasmic interactions between decay-accelerating factor and intercellular adhesion molecule-1 are not required for coxsackievirus A21 cell infection

Coxsackievirus A21 (CAV-21) employs a cell receptor complex of decay-accelerating factor (DAF) and intercellular adhesion molecule-1 (ICAM-1) for cell infectivity. In this study, the nature of potential extra- and/or intracellular interactions between DAF and ICAM-1 involved in picornaviral cell entry was investigated. Firstly, it was shown that intracellular interplay between DAF and ICAM-1 is not required for CAV-21 infection, as CAV-21 lytic infection mediated via the DAF/ICAM-1 receptor complex is not inhibited by replacement of the transmembrane and cytoplasmic domains of ICAM-1 with those from an unrelated cell surface molecule, CD36. By immunoprecipitation, chemical cross-linking and picornaviral binding assays, the existence of a close spatial association between DAF and ICAM-1 on the surface of ICAM-1-transfected RD cells was confirmed. Furthermore, it was shown that potential extracellular DAF/ICAM-1 interactions are likely to occur in an area on or proximal to DAF SCR3 and may influence the route of CAV-21 cell entry.