In order to determine whether the increased susceptibility of MKP-2−/− mice infected with T. gondii was the result of an impaired adaptive immune response spleens were removed and splenocytes stimulated with TLA at days 10, 20 and 30 post-infection and IFN-γ, IL-4, IL-5 and IL-10 production measured in the supernatants. This evidence concerns the gene IFNG and infection.