Major receptor group common cold virus HRV89 was adapted to grow in HEp-2 cells, which are permissive for minor group human rhinoviruses (HRVs) but which only marginally support growth of major-group viruses. After 32 blind passages in these cells, each alternating with boosts of the recovered virus in HeLa cells, HRV89 acquired the capacity to effectively replicate in HEp-2 cells, attaining virus titers comparable to those in HeLa cells although no cytopathic effect was observed. Several clones were isolated and shown to replicate in HeLa cells whose ICAM-1 was blocked with monoclonal antibody R6.5 and in COS-7 cells, which are devoid of ICAM-1. Blocking experiments with recombinant very-low-density lipoprotein receptor fragments and enzyme-linked immunosorbent assays indicated that the mutants bound a receptor different from that used by minor-group viruses. Determination of the genomic RNA sequence encoding the capsid protein region revealed no changes in amino acid residues at positions equivalent to those involved in the interaction of HRV14 or HRV16 with ICAM-1. One mutation was within the footprint of a very-low-density lipoprotein receptor fragment bound to minor-group virus HRV2. Since ICAM-1 not only functions as a vehicle for cell entry but has also a "catalytic" function in uncoating, the use of other receptors must have important consequences for the entry pathway and demonstrates the plasticity of these viruses.Human rhinoviruses (HRVs), a major cause of mild upper respiratory infections generally recognized as common colds, are small icosahedral particles with a capsid composed of four viral proteins, VP1 through VP4 (for a review see reference 9). The capsid encases a genomic RNA of about 7,500 nucleotides encoding a polyprotein which is cotranslationally and autocatalytically processed by three viral proteinases, P2A, P3C, and P3CD (the precursor of P3C). A final maturation cleavage of VP0 to VP2 and VP4 occurs concomitantly with encapsidation by an as yet unidentified protease. With one exception (HRV87), the serotypes can be divided into a major group, using intercellular adhesion molecule 1 (ICAM-1) as the viral receptor, and a minor group, attaching to the cell via members of the low-density lipoprotein receptor (LDLR) family including LDLR, the very-low-density lipoprotein receptor (VLDLR), and LDLR-related protein (LRP) (16,27). The nature of the HRV87 receptor is unknown (50). Whereas major-group viruses are highly specific for human ICAM-1 and fail to attach to the homologue of other species, minor-group viruses bind to a variety of LDLRs, most likely due to the high evolutionary conservation of these membrane proteins. Replication usually does not occur in nonhuman cells even when suitable receptors are present, and adaptation of HRV2 to growth in mouse cells has been shown to be correlated with mutations in nonstructural proteins P2B and P2C (23).As HRVs of both receptor groups are very similar with respect to the amino acid sequence and the three-dimensional structure of the viral cap...