Figure 9A shows the results for IL-8 in media collected from the apical and basolateral sides of uninfected, live wild-type S. Typhi as positive control, filtrate, heat-inactivated S. Typhi, and S. Typhi aro mutants-infected Caco2 monolayers at 22 h post-infection. This evidence concerns the gene CXCL8 and infection.