FIG. 1.

Infection by wild-type (wt) C. rodentium but not the type III secretion mutant ΔescD leads to increased iNOS mRNA expression in colonic tissues. RT-PCR for iNOS demonstrated that infection of immunocompetent C57BL/6 mice with wild-type C. rodentium leads to a progressive and significant elevation in iNOS expression, as seen on days 6 and 10 p.i., compared to that in uninfected (−) mice. In contrast, infection with the ΔescD mutant did not induce iNOS mRNA expression over the same time course. The housekeeping gene GAPDH was used to normalize RNA abundance.