IFNG and influenza: In comparison, mice immunized s.c. with 5 μg X:31 influenza antigen plus 50 μg PCEP responded with an approximately equal number of IL-4 or IFNγ producing T cells in splenocyte population, indicating an antigen-specific mixed Th1 and Th2-type immune response and IL-6 gene expression showing a very strong peak after 24 hrs that then sharply declined [22].