Infected organs show different levels of vaccination-mediated protection.

<p>C57BL/6 mice were orally vaccinated with attenuated SL1344Δ<i>aro</i>A <i>Salmonella</i> Typhimurium. 40–50 day later vaccinated mice and age-matched controls were orally infected with 1×10⁹ of either SL1344 or SL1344Δ<i>aro</i>A. CFU were determined after two days for single PP, mLN, liver and spleen (spl). Symbols indicate individual organs and bold lines median CFU from 9 or more mice pooled from 2 independent experiments. Numbers indicate organs displaying less than 10 CFU.