CCL20 (MIP-3α) is expressed in response to flagellated bacteria, regardless of their invasiveness. Ileal ligated loops were carried out in the intestine of C57BL/6 mice. 10⁸ CFU of bacteria (S typhimurium: SL-WT; B subtilis: BS; L plantarum: LP) were injected into the loops. CTRL indicates control mice injected with PBS. Mice were killed at the indicated time points. Cryosections were stained with anti-CCL20 antibody (green) and with TO-PRO (blue) to detect nuclei. BS is a flagellated noninvasive bacterium and induces CCL20, whereas LP that is not flagellated does not. One of 2 independent experiments is shown.