IL1RL1 and infection: Considering that one of the main routes of the Brucella infection is through oral surfaces, we assessed the susceptibility of wild-type (WT) mice and animals deficient for the ST2 receptor (ST2−/−) to oral infection with Brucella abortus, by determining the number of colony forming units in livers and spleens, 3to 14 days post-infection.