TNF and infection: Pretreatment of IPEC-J2 cells (on insert membranes) followed by a 2 h infection with ETEC resulted in decreased mRNA levels for IL-1β, TLR5 (P < 0.001), and MyD88 (P < 0.05), but increased mRNA levels for IL-8, TNF-α (P < 0.001), and IL-6 (P < 0.01) compared to the control group of IPEC-J2 cells.