How viruses use the immune system to promote infection of polarized cells

The Mechanism of PEDV-Carrying CD3+ T Cells Migrate into the Intestinal Mucosa of Neonatal Piglets

Porcine epidemic diarrhea virus (PEDV) can cause intestinal infection in neonatal piglets through the nasal cavity. A process in which CD3⁺ T cells carry PEDV plays a key role. However, the modes through which PEDV bridles CD3⁺ T cells as a vehicle for migration to the intestinal epithelium have not been clarified. In this study, we first demonstrated that PEDV could survive in blood-derived CD3⁺ T cells for several hours, depending on the multiplicity of infection. In addition, PEDV preferentially survived in CD4⁺ T cells over CD8⁺ T cells. Moreover, viral transmission was mediated by cell-to-cell contact between mesenteric lymph-node-derived CD3⁺ T cells, but did not occur in blood-derived CD3⁺ T cells. Following an increase in gut-homing integrin α4β7, blood-derived CD3⁺ T cells carrying PEDV migrated to the intestines via blood circulation and transferred the virus to intestinal epithelial cells through cell-to-cell contact in neonatal piglets. Our findings have significant implications for understanding PEDV pathogenesis in neonatal piglets, which is essential for developing innovative therapies to prevent PEDV infection.