Such mice exhibit a wide variety of immunological aberrations including suboptimal IgG responses to antigenic stimulation (84), a higher catabolic rate of IgG (47) and albumin (85), hepatic and splenic iron overload (86–89), impaired interferon gamma (IFN-γ), and other cytokine responses (90–92), higher susceptibility to parasitic (93), mycobacterial (94, 95), certain viral (90, 96) and gram (−) infections (97, 98) as well as a higher susceptibility to virus induced tumors (99, 100). This evidence concerns the gene IFNG and infection.