IL4 and escherichia coli infection: However, E. coli infection before AAD phase suppressed Th2 cytokines IL-4 and serum IgE production, but in contrast enhanced Th1 cytokines IFN-γ and IL-2 production, Moreover, this effects were more significantly in the (108infN+OVA) group than the (106infN+OVA) and (108infA+OVA) group.