In this study, an infection assay was used to quantify the release of pro- and anti-inflammatory cytokines (IL8, IL1β, IL6, IL10, TNF, and IL12p70) from intestinal cells (HT-29 and HuTu 80) after 4 h of infection with the ETEC strain E9034A and the generated mutants (E9034AΔlngA, E9034AΔcstH, E9034AΔfliC, E9034AΔlngAΔfliC, E9034AΔlngAΔcstH, E9034AΔlngAΔfliC, and E9034AΔcstHΔfliC, and E9034AΔlngAΔcstHΔfliC). Here, IL6 is linked to infection.