NFκB migrates to the nucleus after cell interaction with high-binders, but not low-binders, 4 hours after inoculation with bacteria. NFκB is detected as a dark brown stain against a pale lavender background. 3A, negative control. 3B, A549 incubated with serotype 3 low-binders (Black arrow shows NFκB protein in the cytoplasm). 3C, A549 incubated with serotype 3 high-binders (White arrow shows NFκB protein detected in the nucleus).