PIGR and infection: Subsequent in vitro studies in polarized epithelial cells showed that the murine anti-VP6 IgA monoclonal antibody 7D9 inhibited RV replication inside epithelial cells at an early stage of infection [24], which later was shown to depend on transcytosis of dimeric IgA mediated by the polymeric immunoglobulin receptor (pIgR) [25].