Interactions of enterotropic mouse hepatitis viruses with Bgp2 receptor proteins.

Enterotropic mouse hepatitis virus (MHV) infections are limited to the intestinal mucosa, rarely disseminate to other tissues and cause disease only in neonatal mice. The role of virus-host cell receptor interactions in the limited tissue tropism of enterotropic MHV infections is unclear. Previous studies have shown that enterotropic MHV-Y can infect BHK cells stably transfected with either the MHVR or the mmCGM2 receptor gene. In contrast, enterotropic MHV-RI infects BHK cells stably transfected with the MHVR but not the mmCGM2 receptor gene. Studies to determine whether MHV-Y and -RI can utilize the Bgp2 receptor isoform were performed. Both MHV-Y and -RI infected Vero cells transiently transfected with the Bgp2 receptor gene, though only MHV-Y infected CHO cells stably transfected with the Bgp2 receptor gene. Additionally, pretreatment with anti-MHVR monoclonal antibody (CC1) did not prevent MHV-Y and -RI infection of CMT93 cells. In contrast, pretreatment with CC1 prevented MHV-A59 infection of CMT93 cells. It is likely that MHV-Y and -RI use the Bgp2 receptor to infect CC1 pretreated CMT93 cells, since CMT93 cells are known to possess high levels of the Bgp2 receptor mRNAs, but it is also possible that they use an unidentified receptor.