CHINESE-HAMSTER OVARY CELLS ARE NONPERMISSIVE TOWARDS INFECTION WITH COXSACKIEVIRUS B3 DESPITE FUNCTIONAL VIRUS-RECEPTOR INTERACTIONS

Viral infection is a complex process which includes binding and intera ction of the virus with specific cell surface receptors, uptake and un coating of the virus, and finally replication. Chinese hamster ovary ( CHO) cells are non-permissive towards infection with coxsackieviruses of group B (CVB), although they do express a putative CVB-specific rec eptor protein. In order to localize the block of infection in CHO cell s, these cells were tested for binding of radiolabelled CVB3, receptor -mediated transformation of virions into A-particles, and replication of the viral genome. Binding of CVB3 to CHO cells was found to be comp arable to the binding of this virus to permissive cell lines. Detergen t-solubilized membrane proteins of CHO cells were tested in virus over lay protein-binding assays (VOPBAs) and shown to express a 100 kDa CVB -binding membrane protein similar to the CVB receptor protein which we recently described for permissive HeLa cells. Incubation of CVB3 with intact CHO cells resulted in transformation of cell-bound virions int o non-infectious A-particles (deprived of capsid protein VP4), demonst rating the functional activity of the CVB receptor protein on CHO hams ter cells. Transfection of recombinant CVB3 cDNA or viral RNA into CHO cells resulted in the production of infectious CVB3 virions, implying that the failure of CVB to infect CHO cells is not caused by a defect in virus replication but results from a block in the uptake of virus particles into the cell after the initial steps of virus-receptor inte ractions. (C) 1997 Elsevier Science B.V.