Rotaviruses require basolateral molecules for efficient infection of polarized MDCKII cells.

In this work we evaluated the ability of rotavirus strains with different receptor requirements to infect the apical and basolateral surfaces of polarized MDCKII cells. We used neuraminidase (NA)-sensitive (RRV and TFR-1) and neuraminidase-resistant (Wa and UK) viruses that differ in their use of integrins. Regardless of their receptor requirements, all virus strains tested were found to efficiently infect cells from both membrane surface domains, with preference for the basolateral domain, since: (i) disruption of tight junctions of polarized cell monolayers by calcium chelation led to a reversible increase of rotavirus infectivity, (ii) the viruses infected preferentially the cells located at the borders of microcolonies of polarized cells, and (iii) in cells grown on a permeable support all four virus strains were able to start the infection by either plasma membrane domain. Preferential infection (5-11-fold more efficiently) of the basolateral surface correlated with the neuraminidase resistance of the virus strains, but not with their requirement for integrins, which in MDCKII cells seem to be used by all four viruses. The infection of both cell surface domains by RRV was found to depend on the presence of terminal sialic acids, since its infectivity was reduced by neuraminidase treatment of the cells and it was also blocked by incubation of the virus with glycophorin A. The efficient infection through the basolateral membrane surface of polarized cells might be relevant for the pathogenesis of rotavirus, especially given the recent reports of antigenemia and extraintestinal spread of the virus in children and animal models.