MAPK3 and infection: Thus, ERK1/2 pathway blockage caused the highest inhibition of IL-8 secretion induced by EAEC infection at 2 h (73%) and 4 h (63%) of infection, while the lowest inhibition was induced in cells infected for 2 h by S. flexneri (49%), EHEC (48.5%), or EIEC (47%), and at 4 h IL-8 secretion was inhibited 74–64% during infection by ETEC>EHEC>EPEC>EIEC>EAEC, while lowest inhibition (43%) was during the infection by S. flexneri.