IgA-coated particles of Hepatitis A virus are translocalized antivectorially from the apical to the basolateral site of polarized epithelial cells via the polymeric immunoglobulin receptor.

Although Hepatitis A virus (HAV) is transmitted by the faecal-oral route, its target for replication is the liver. Little is known of its interactions with cells of the gastrointestinal tract, and it is not known by which mechanisms HAV crosses the intestinal epithelium. In this study, it is shown that HAV associated with IgA is translocated from the apical to the basolateral compartment of polarized epithelial cells via the polymeric immunoglobulin receptor by IgA-mediated reverse transcytosis. The relevance of this mechanism, by which HAV-IgA complexes may overcome the intestinal barrier and contribute to infections of the liver, results from the fact that HAV-IgA complexes are infectious for hepatocytes and that significant amounts of intestinal HAV-IgA are present during acute infections, which are also partly transmitted. Besides supporting the primary infection, this mechanism may play a role in relapsing infections by establishing an enterohepatic cycle for HAV.