IL4 and infection: Furthermore, the in vivo response to WIV in mice resembled that to infection by live influenza virus which is known to be Th1-dominated with large amounts of IgG2a/c and IFNγ-producing T cells [8,24,25,27,28], whereas SV and SU vaccines elicit a Th2 dominated response characterized by IgG1 and Il-4-producing Th cells [8,24,25].