Colonic matrixmetalloproteinase-2 expression following C. jejuni infection of infant mice. Immediately after weaning, infant mice were perorally infected with C. jejuni NCTC11168 (WT, closed circles) or the mutant strain NCTC11168∆htrA (∆htrA, open circles). Uninfected animals (Naïve; open diamonds) served as negative controls. (A) MMP-2 and (B) TIMP-1 mRNA expression levels were determined in colonic ex vivo biopsies taken at day 7 p.i. by quantitative real-time PCR. Numbers of analyzed animals are given in parentheses. Means (black bars) and levels of significance (P-values) determined by the Mann–Whitney-U test are indicated. Data shown were pooled from three independent experiments.