Caco2bbe

T84 intestinal epithelial cells purchased from the American Type Culture Collection (Manassas, Va) were grown and maintained in a 1:1 (vol:vol) mixture of Dulbecco modified Eagle medium and Ham F-12 medium containing L-glutamine (0.365 g/L) and sodium bicarbonate (2.438 g/L), supplemented with fetal bovine serum (10%) and 2% penicillin-streptomycin at 37°C in 5% CO 2 (all from Invitrogen, Burlington, Ontario, Canada).
Caco-2 bbe (American Type Culture Collection, labeled Caco-2 hereafter) cells were grown and maintained in Dulbecco modified Eagle medium containing L-glutamine (0.584 g/L) and supplemented with 10% fetal bovine serum, 2% penicillin-streptomycin, sodium pyruvate (1 mM), and human transferrin (0.01 mg/mL) at 37°C in 5% CO 2 (all from Invitrogen).
Recombinant human TGF-β1 (TGF-β throughout text, unless otherwise specified), TGF-β2, or latent TGF-β (R&D Systems Inc, Minneapolis, Minn) were added into the basolateral side of wells (0.1 -100 ng/mL, 1 -72 h), and transepithelial electrical resistance (TER) was recorded throughout the experimental period.
Enterohemorrhagic E. coli O157:H7 strain CL56 ( 11 ) was maintained on 5% sheep blood agar plates (Oxiod, Nepean, Ontario, Canada) at 4°C, cultured overnight in nonaerated Luria-Bertani broth at 37°C, and then added to the apical compartment of intestinal epithelia at approximately 1 × 10 8 colony-forming units/monolayer.