The information reviewed above highlights the important roles that TLRs play in the regulation of the inflammatory response at mucosal surfaces. However, it is well known that these mucosal surfaces are constantly bathed in bacteria, and yet appear to mount little, if any, inflammatory response. These observations lead to the question, "What controls the activation of TLRs during basal states, and what leads to their activation during inflammatory conditions?" While a complete answer to this question remains lacking, current evidence suggests that the regulation of TLR activity occurs through altering TLR or co-receptor expression, TLR localization, TLR polarity, or signaling intermediate or negative regulatory protein expression, as described below.