NF-κB activation and cytokine secretion after concomitant stimulation with E. coli and L. rhamnosus GR-1. Bladder cells were challenged for 24 h with heat-killed E. coli alone or together with viable (V) or heat-killed (HK) L. rhamnosus GR-1. (A) Relative NF-κB activation (n = 4). (B) TNF, IL-6 and CXCL8 levels (n = 3) were measured. Bars labeled "a" are significantly different from control and "b" significantly different from cells stimulated with E. coli (p-values < 0.05).