Hence IFN-γ expression by Th2/1 cells in reactive lymph nodes or the spleen, where their proportion is relatively high, might contribute to the diversification of antibody responses and assure that antibodies primarily involved in opsonization of pathogens or their secreted components do not go short in Th2-associated infections mainly driving IgE and IgG4 production by B cells. This evidence concerns the gene IFNG and infection.