Early Events in Infection: Receptor Binding and Cell Entry

Abstract

As knowledge of the early events in infection with enteroviruses is limited, this chapter focuses on studies with poliovirus but examines the emerging data on several other enteroviruses. The early events in virus infection, from virus binding to uncoating of the viral genome, are well characterized for a number of enveloped viruses. The poliovirus-receptor interaction is a particularly good model for studying virus entry because of the experimental manipulations that are possible given the known structure of the virus and our ability to mutagenize both the virus and its cellular receptor. Despite our increasing genetic and structural understanding of early events in poliovirus infection, many problems, such as the location of the uncoating event, remain unsolved. Perhaps imminent studies on the entry of echoviruses (ECVs) and coxsackieviruses, stimulated by the identification of their receptors, will provide clues. The roles of receptors in host range and pathogenesis have been extensively studied for poliovirus, but many questions, such as the basis of tissue tropism, remain. A study of the cell functions of virus receptors may provide information on their role in virus replication. It has been suggested that virus binding to cell receptors may lead to activation of cell events that lead to disease, and there is evidence that receptors may regulate virus-induced cytopathic effects. Studies of the interactions of cell receptors with their natural cell ligands may therefore provide clues about cell processes that are activated upon virus binding and govern the outcome of virus infections.