IL6 and infection: After infection of CIECs with 106 CFU/ml C. jejuni 11168, Lior6 or 0097, the expression patterns of the interleukin (IL)-1β and IL-6 mRNAs, which are proinflammatory cytokines known to be upregulated after C. jejuni infection of chickens [23, 24], were investigated via qRT‒PCR.