Human cytomegalovirus infects Caco-2 intestinal epithelial cells basolaterally regardless of the differentiation state

Human cytomegalovirus (CMV) causes severe disease in immunosuppressed patie nts and notably infects the gastrointestinal tract. To understand the inter action of CMV with intestinal epithelial cells, which are highly susceptibl e to CMV infection in vivo, we used the intestinal epithelial cell line Cac o-2 and demonstrated that CMV enters predominantly through the basolateral surface of polarized Caco-2 cells. As shown by expression of all three clas ses of CMV proteins and by visualization of nucleocapsids by transmission e lectron microscopy, both poorly and fully differentiated Caco-2 cells were permissive to CMV replication. However, infection failed to produce infecti ous particles in Caco-2 cells, irrespective of the state of differentiation .