For example, S100A8 and S100A9 (calprotectin) constitute ~45% of the cytoplasmic content of neutrophils and is used as a non-invasive faecal biomarker for assessing colonic inflammation in IBD.24 We therefore tested if neutrophil numbers vary following C. rodentium infection of C57 and C3H mice. Here, S100A9 is linked to inflammatory bowel disease.