IL17C and mucositis: In contrast, challenge of epithelial tissues with a similar load of the potential pathobiont F. nucleatum, associated with more severe mucositis, produced a dramatic upregulation of TNF, IL17C, CCL20, and CXCL2. We also observed that F. nucleatum induced an upregulation of PMAIP1 and, consistent with this effect, tissues displayed death of cells in the apical layer (Fig. 5e).