Human and most animal rotavirus strains do not require the presence of sialic acid on the cell surface for efficient infectivity

The outer capsid spike protein VP4 is the main rotavirus cell attachment pr otein, but the cellular receptor used by rotavirus to establish a productiv e infection remains unknown. Sialic acid (SA) residues on the cell surface have been shown to be required for efficient binding and infectivity of ani mal rotaviruses (ARVs), but not of human rotaviruses (HRVs). Since the SA d ependence of only a limited number of strains has been tested to date, in t his study a larger number of strains were tested to further investigate the involvement of SA in rotavirus infectivity, Following treatment of African green monkey kidney cell (MA104) monolayers with neuraminidase, productive infection of rotavirus was measured by immunofluorescence. The infectivity of all 14 HRVs tested was SA-independent. Ten of 15 ARVs tested were SA-in dependent, while only five were SA-dependent. These results indicate that m ost ARVs, like HRVs, infect permissive cells in an SA-independent manner, p robably by a common cellular receptor.