Since TLR signaling is an important component bridging innate and adaptive immunity (Iwasaki and Medzhitov, 2004) , failure to clear Brucella from organs by TLR signaling deficient mice could be due to defects in the development of adaptive immunity. To test this hypothesis, we determined cellular-and humoral-mediated adaptive immunity in these TLR knockout mice following Brucella infection. The results reveal that TLR signaling exhibits significant differences in control and clearance of Brucella from selected tissues and in the associated development of an adaptive immune response.