INVASIVENESS OF SHIGELLA-FLEXNERI IN POLIOVIRUS INFECTED HT-29 CELLS

In this paper we report the effect in HT-29 cells of mixed infections with poliovirus type 1 and Shigella flexneri serotype 5 strain M90T an d derivative strains differing in adhesive as well as invasive propert ies. HT-29 epithelial intestinal cells derived from a human colon aden ocarcinoma are a good model for coinfection studies because they are s usceptible both to poliovirus replication and to S. flexneri invasion. The results show that 48 h after infection by poliovirus the invasive ness of wild-type S. flexneri M90T and of its adherent and invasive de rivative M90T (pIL22) is increased. However, the alterations produced in HT-29 cells at the later stage of poliovirus infection are not suff icient to promote the internalization of simply non invasive, or non i nvasive but adherent, isogenic derivative bacterial strains.