Many serotypes of echovirus (EV) and Coxsackie B virus (CBV) bind human decay-accelerating factor (DAF) and use it as a receptor for infection. Analogues for DAF have been isolated from mice and rats and characterized; these analogues have amino acid identities to human DAF of ∼60%. EV serotypes 3, 6 , 7, 11-13, and 29 and CBV serotypes 1, 3, and 5 caused hemagglutination of human erythrocytes but not rat or mouse erythrocytes, suggesting failure to bind rodent DAF. To confirm this evidence,

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... iolabeled viruses were incubated with transfected Chinese hamster ovary (CHO) cells that were abundantly expressing each type of DAF. Only cells that expressed human DAF bound virus. Although binding of EV and CBV was specific for human DAF, complement inhibition by DAF expressed in CHO cells was similar for each analogue. Viruses initiate infection by attaching to cell-surface receptor molecules; thus, expression of specific receptors is an important determinant of viral host range and tissue tropism. Echoviruses (EVs [enteric cytopathic human orphan viruses]) and Coxsackie B viruses (CBVs) are members of the Enterovirus genus, family Picornaviridae. The wide range of clinical sequelae associated with EV and CBV infection includes rashes, diarrhea, aseptic meningitis, respiratory disease, myocarditis, and nonspecific febrile illness. The range of clinical manifestations probably reflects virus-tissue tropisms that are mediated, at least in part, by differential use of receptors. Those EV serotypes that hemagglutinate human erythrocytes, including serotypes 3, 6, 6 , 7, 11-13, 19, 21, 24, 25, 29, 30, and 33, bind decay-accelerating factor (DAF; CD55) on the erythrocyte [1, 2]. DAF comprises four 60-amino acid short consensus repeats (SCRs), a heavily O-glycosylated region, and a glycolipid anchor (reviewed in [3] ). DAF plays a central role in regulating the complement system by dissociating the con-