We chose to use T24 cells as they have been shown to be similar to primary human bladder epithelial cells, first in that they express Toll-like receptor 4 and therefore they are sensitive to stimulation by lipopolysaccharide (LPS), and also because they have been used in several studies as responsive to infection with Gram-negative bacteria commonly associated with UTIs [21,22]. Here, TLR4 is linked to infection.